Chinese Physics C

Diffuseness effect and radial basis function network to optimize the calculation of α decay

Na-Na MA, Xiao-Jun BAO, Hong-Fei ZHANG

Published:

Abstract:
Radial basis function network (RBFN) approach is adopted for the first time to optimize the calculation of

\begin{document}$ \alpha $\end{document}

decay half-life in the generalized liquid drop model (GLDM) concurrently incorporating the surface diffuseness effect. Calculations of the present study are in good agreement with the experimental half-lives for 68 superheavy nuclei (SHN), and a remarkable reduction of 40% in the root-mean-square (rms) deviations of half-lives is achieved. After that, based on RBFN method, the half-lives for four SHN isotopes, ^252-288Rf, ^272-310Fl, ^286-316119 and ^292-318120, are predicted using the improved GLDM with the diffuseness correction and the decay energies from WS4 and FRDM as inputs. Hence, we conclude that the diffuseness effect should be embodied in the proximity energy. Simultaneously, the neural network methods are encouraged to widely used in nuclear reaction.

The universal function of the diffractive process in color dipole picture

Z. Jalilian, G. R. Boroun

Published:

Abstract:
In this presentation, we obtain the corresponding universal function to the diffractive process and show the cross section exhibits the geometrical scaling. It is observed the diffractive theory according to the color dipole approach at small-x is a convenient framework that reveals the color transparency and the saturation phenomena. Also we calculate the contribution of heavy quark productions in the diffractive cross section for high energy that is determined by the small size dipole configuration. The ratio of the diffractive cross section to the total cross section in the electron-proton collision is the other important quantity that is computed in this work.

The complete study on polarization of $ {\Upsilon }$(nS) hadroproduction at QCD next-to-leading order

Yu Feng, Bin Gong, Chao-Hsi Chang, Jian-Xiong Wang

Published:

Abstract:
Applying the nonrelativistic quantum chromodynamics factorization formalism to the

\begin{document}$ \Upsilon(1S,2S,3S) $\end{document}

hadroproduction, a complete analysis on the polarization parameters

\begin{document}$ \lambda_{\theta} $\end{document}

,

\begin{document}$ \lambda_{\theta\phi} $\end{document}

,

\begin{document}$ \lambda_{\phi} $\end{document}

for the production are presented at QCD next-to-leading order. With the long-distance matrix elements extracted from experimental data for the production rate and polarization parameter

\begin{document}$ \lambda_{\theta} $\end{document}

of

\begin{document}$ \Upsilon $\end{document}

hadroproduction, our results provide a good description for the measured parameters

\begin{document}$ \lambda_{\theta\phi} $\end{document}

and

\begin{document}$ \lambda_{\phi} $\end{document}

in both the helicity and the Collins-Soper frames. In our calculations the frame invariant parameter

\begin{document}$ \tilde{\lambda} $\end{document}

is consistent in the two frames. Finally, it is pointed out that there are discrepancies for

\begin{document}$ \tilde{\lambda} $\end{document}

between available experimental data and corresponding theoretical predictions.

Improved empirical formula for α particle preformation factor

Yan He, Xuan Yu, Hongfei Zhang

Published:

Abstract:
In this contribution, the

\begin{document}$\alpha$\end{document}

preformation factors of 606 nuclei are extracted within the framework of generalized liquid drop model (GLDM). Through the systematically analysis of the

\begin{document}$\alpha$\end{document}

preformation factors of even-even Po-U isotopes, we found there is a significant weakening of influence of

\begin{document}$N=126$\end{document}

shell closure in uraninum, which is consistent with the result of a recent experiment [J. Khuyagbaatar et al., Phys. Rev. Lett. 115.242502 (2015)], implying that

\begin{document}$N=126$\end{document}

may be not the magic number for U isotopes. Furthermore, we propose an improved formula with only 7 parameters to calculate

\begin{document}$\alpha$\end{document}

preformation factors suitable for all types of

\begin{document}$\alpha$\end{document}

-decay, which has fewer parameters than the original formula proposed by Zhang et al. [H. F. Zhang et al., Phys. Rev. C 80.057301 (2009)] with high precision. The standard deviation of the

\begin{document}$\alpha$\end{document}

preformation factors calculated by our formula with extracted values for all 606 nuclei is 0.365 with a factor of 2.3, indicating that our improved formula can accurately reproduce the

\begin{document}$\alpha$\end{document}

preformation factors. Encouraged by this, the

\begin{document}$\alpha$\end{document}

-decay half-lives of actinide elements are predicted, which could be useful in future experiments. Noticeably, the predicted

\begin{document}$\alpha$\end{document}

-decay half-lives of two new isotopes

\begin{document}$^{220}$\end{document}

Np [Z.Y. Zhang, et al., Phys. Rev. Lett. 122. 192503 (2019)] and

\begin{document}$^{219}$\end{document}

Np [H. B. Yang et al., Phys. Lett. B 777, 212 (2018)] are in good agreement with the experimental

\begin{document}$\alpha$\end{document}

-decay half-lives.

Theory for quarkonium: from NRQCD factorization to soft gluon factorization

An-Ping Chen, Yan-Qing Ma

Published:

Abstract:
We demonstrate that the recently proposed soft gluon factorization (SGF) is equivalent to the nonrelativistic QCD (NRQCD) factorization for heavy quarkonium production or decay, which means that for any given process these two factorization theories are either both valid or both violated. We use two methods to achieve this conclusion. In the first method, we apply the two factorization theories to the physical process

\begin{document}$J/\psi \to e^+e^-$\end{document}

. Our explicit calculation shows that both SGF and NRQCD can correctly reproduce low energy physics of full QCD, and thus the two factorizations are equivalent. In the second method, by using equations of motion we successfully deduce SGF from NRQCD effective field theory. By identifying SGF with NRQCD factorization, we establish relations between the two factorization theories and prove the generalized Gremm-Kapustin relations as a by product. Comparing with the NRQCD factorization, the advantage of SGF is that it resums the series of relativistic corrections originated from kinematic effects to all powers, which gives rise to a better convergence in relativistic expansion.

The eccentricity enhancement effect of intermediate-mass-ratio-inspirals: dark matter and black hole mass

Meirong Tang, Zhaoyi Xu, Jiancheng Wang

Published:

Abstract:
It was found that the dark matter (DM) in the intermediate-mass-ratio-inspiral (IMRI) system has a significant enhancement effect on the orbital eccentricity of the stellar massive compact object, such as a black hole (BH), which may be tested by space-based gravitational wave (GW) detectors including LISA, Taiji and Tianqin in future observations [1]. In this paper, we will study the enhancement effect of the eccentricity for an IMRI under different DM density profiles and center BH masses. Our results are as follows: (1) in terms of the general DM spike distribution, the enhancement of the eccentricity is basically consistent with the power-law profile, which indicates that it is reasonable to adopt the power-law profile; (2) in the presence of DM spike, the different masses of the center BH will affect the eccentricity, which provides a new way for us to detect the BH's mass; (3) considering the change of the eccentricity in the presence and absence of DM spike, we find that it is possible to distinguish DM models by measuring the eccentricity at the scale of about

\begin{document}$ 10^{5} GM/c^{2} $\end{document}

.

The entanglement properties of holographic QCD model with a critical end point

Zhibin Li, Kun Xu, Mei Huang

Published:

Abstract:
We investigate different entanglement properties of a holographic QCD (hQCD) model with a critical end point at finite baryon density. Firstly we consider the holographic entanglement entropy (HEE) of this hQCD model in a spherical shaped region and a strip shaped region, respectively, and find that the HEE of this hQCD model in both regions can reflect QCD phase transition. What is more is that although the area formulas and minimal area equations of the two regions are quite different, the HEE have very similar behavior on the QCD phase diagram. So we argue that the behavior of HEE on the QCD phase diagram is independent of the shape of subregions. However, as we know that HEE is not a good quantity to characterize the entanglement between different subregions of a thermal system. So we then study the mutual information (MI), conditional mutual information (CMI) and the entanglement of purification (Ep) in different strip shaped regions. We find that the three entanglement quantities show some universal behavior: their values do not change so much in the hadronic matter phase and then rise up quickly with the increase of T and

\begin{document}$ \mu$\end{document}

in the QGP phase. Near the phase boundary, these three entanglement quantities change smoothly in the crossover region, continuously but not smoothly at CEP and show discontinuity behavior in the first phase transition region. And all of them can be used to distinguish different phases of strongly coupled matter.

Lorentz Violation, Quantum Tunneling and Information Conservation

Guo-Ping Li, Ke-Jian He, Bing-Bing Chen

Published:

Abstract:
In this paper, by introducing a Lorentz-invariance-violation (LIV) class of dispersion relations (DR) suppressed by the second power

\begin{document}$ (E/E_{QG})^2 $\end{document}

, we have investigated the effect of LIV on the Hawking radiation of the charged Dirac particle via tunneling from a Reissner-Nordström(RN) black hole. We first find the effect of LIV speeds up the black hole evaporation, leaving the induced Hawking temperature very sensitive to the changes in the energy of the radiation particle, but at the same energy level, insensitive to the changes in the charge of the radiation particle. This provides a phenomenological evidence for the LIV-DR as a candidate for describing the effect of quantum gravity. Then, when the effect of LIV is included, we find the statistical correlations with the Planck-scale corrections between the successive emissions can leak out the information through the radiation. And, it turns out that the black hole radiation as tunneling is an entropy conservation process, and no information loss occurs during the radiation, where the interpretation for the entropy of black hole is addressed. Finally, we conclude that black hole evaporation is still an unitary process in the context of quantum gravity.

Strongly lensed gravitational waves as the probes to test the cosmic distance duality relation

Hai-Nan Lin, Xin Li, Li Tang

Published:

Abstract:
The cosmic distance relation (DDR) associates the angular diameters distance (

\begin{document}$ D_A $\end{document}

) and luminosity distance (

\begin{document}$ D_L $\end{document}

) by a simple formula, i.e.,

\begin{document}$ D_L = (1+z)^2D_A $\end{document}

. The strongly lensed gravitational waves (GWs) provide a unique way to measure

\begin{document}$ D_A $\end{document}

and

\begin{document}$ D_L $\end{document}

simultaneously to the GW source, hence can be used as probes to test DDR. In this paper, we prospect the use of strongly lensed GW events from the future Einstein Telescope to test DDR. We write the possible deviation of DDR as

\begin{document}$ (1+z)^2D_A/D_L = \eta(z) $\end{document}

, and consider two different parametrizations of

\begin{document}$ \eta(z) $\end{document}

, namely,

\begin{document}$ \eta_1(z) = 1+\eta_0 z $\end{document}

and

\begin{document}$ \eta_2(z) = 1+\eta_0 z/(1+z) $\end{document}

. Numerical simulations show that, with about 100 strongly lensed GW events observed by ET, the parameter

\begin{document}$ \eta_0 $\end{document}

can be constrained at 1.3% and 3% levels for the first and second parametrizations, respectively.

Neutron star cooling and GW170817 constraint within quark-meson coupling models

Odilon Lourenço, César H. Lenzi, Mariana Dutra, Tobias Frederico, M. Bhuyan, Rodrigo Negreiros, César V. Flores, Guilherme Grams, Débora P. Menezes

Published:

Abstract:
In the present work, we used five different versions of the quark-meson coupling (QMC) model to compute astrophysical quantities related to the GW170817 event and neutron star cooling process. Two of the models are based on the original bag potential structure and three versions consider a harmonic oscillator potential to confine the quarks. The bag-like models also incorporate the pasta phase used to describe the inner crust of neutron stars. Within the simple method studied in the present work, we show that the pasta phase does not play a significant role. Moreover, the QMC model that satisfies the GW170817 constraints with the lowest slope of the symmetry energy exhibits a cooling profile compatible with observational data.

Calculation of Feynman loop integration and phase-space integration via auxiliary mass flow

Xiao Liu, Yan-Qing Ma, Wei Tao, Peng Zhang

Published:

Abstract:
We extend the auxiliary-mass-flow (AMF) method originally developed for Feynman loop integration to calculate integrals involving also phase-space integration. Flow of the auxiliary mass from the boundary (

\begin{document}$\infty$\end{document}

) to the physical point (

\begin{document}$0^+$\end{document}

) is obtained by numerically solving differential equations with respective to the auxiliary mass. For problems with two or more kinematical invariants, the AMF method can be combined with traditional differential-equation method by providing systematical boundary conditions and highly nontrivial self-consistent check. The method is described in detail with a pedagogical example of

\begin{document}$e^+e^-\rightarrow \gamma^* \rightarrow t\bar{t}+X$\end{document}

at NNLO. We show that the AMF method can systematically and efficiently calculate integrals to high precision.

Resolving Hubble Tension with Quintom Dark Energy Model

Sirachak Panpanich, Piyabut Burikham, Supakchai Ponglertsakul, Lunchakorn Tannukij

Published:

Abstract:
Recent low-redshift observations give value of the present-time Hubble parameter

\begin{document}$H_{0}\simeq 74\;\rm{km s}^{-1} \rm{Mpc}^{-1}$\end{document}

, roughly 10% higher than the predicted value

\begin{document}$H_{0}=67.4\;\rm{km s}^{-1}\rm{Mpc}^{-1}$\end{document}

from Planck's observations of the Cosmic Microwave Background radiation (CMB) and the

\begin{document}$\Lambda$\end{document}

CDM model. Phenomenologically, we show that by adding an extra component X with negative density in the Friedmann equation, it can relieve the Hubble tension without changing the Planck's constraint on the matter and dark energy densities. For the extra negative density to be sufficiently small, its equation-of-state parameter must satisfy

\begin{document}$1/3\leq w_{X}\leq1$\end{document}

. We propose a quintom model of two scalar fields that realizes this condition and potentially alleviate the Hubble tension. One scalar field acts as a quintessence while another “phantom” scalar conformally couples to matter in such a way that viable cosmological scenario can be achieved. The model depends only on two parameters,

\begin{document}$\lambda_{\phi}$\end{document}

and

\begin{document}$\delta$\end{document}

which represent rolling tendency of the self-interacting potential of the quintessence and the strength of conformal phantom-matter coupling respectively. The toy quintom model with

\begin{document}$H_{0}=73.4\;\rm{km s}^{-1}\rm{Mpc}^{-1}$\end{document}

(Quintom I) gives good Supernovae-Ia luminosity fits, decent

\begin{document}$r_{\rm BAO}$\end{document}

fit, but slightly small acoustic multipole

\begin{document}$\ell_{A}=285.54$\end{document}

. Full parameter scan reveals that quintom model provide better model than the

\begin{document}$\Lambda$\end{document}

CDM model in certain region of the parameter space,

\begin{document}$0.02<\delta<0.10, \Omega_{m}^{(0)}<0.31$\end{document}

, while significantly relieving Hubble tension even though not completely resolving it. A benchmark quintom model, Quintom II, is presented as an example.

Effects of vector leptoquarks on $\Lambda_b \rightarrow \Lambda_c \ell \overline{\nu}_\ell$ decay

K. Azizi, A. T. Olgun, Z. Tavukoğlu

Published:

Abstract:
Experimental data on

\begin{document}$ R(D^{(*)}) $\end{document}

,

\begin{document}$ R(K^{(*)}) $\end{document}

and

\begin{document}$ R(J/\psi) $\end{document}

, provided by different collaborations, show sizable deviations from the standard model (SM) predictions. To describe these anomalies many new physics scenarios have been proposed. One of them is leptoquark model with introducing the vector and scalar leptoquarks coupling simultaneously to the quarks and leptons. To look for similar possible anomalies in baryonic sector, we investigate the effects of a vector leptoquark

\begin{document}$U_3 (3,3, \frac{2}{3})$\end{document}

on various physical quantities related to the tree-level

\begin{document}$ \Lambda_b \rightarrow \Lambda_c \ell ~ \overline{\nu}_\ell$\end{document}

decays (

\begin{document}$ \ell=\mu, ~\tau $\end{document}

), which proceed via

\begin{document}$ b \rightarrow c~\ell ~ \overline{\nu}_\ell$\end{document}

transitions at quark level. We calculate the differential branching ratio, forward-backward asymmetry and longitudinal polarizations of lepton and

\begin{document}$\Lambda_{c}$\end{document}

baryon at

\begin{document}$ \mu $\end{document}

and

\begin{document}$ \tau $\end{document}

lepton channels in leptoquark model and compare their behavior with respect to

\begin{document}$ q^2 $\end{document}

with the predictions of the SM. In the calculations we use the form factors calculated in full QCD as the main inputs and take into account all the errors coming from the form factors and model parameters. It is observed that, at

\begin{document}$ \tau $\end{document}

channel, the

\begin{document}$ R_A $\end{document}

fit solution to data related to the leptoquark model sweeps some regions out of the SM band but it has a considerable intersection with the SM predictions. The

\begin{document}$ R_B$\end{document}

type solution gives roughly the same results with the those of the SM on

\begin{document}$ DBR(q^2)-q^2$\end{document}

. At

\begin{document}$ \mu $\end{document}

channel, the leptoquark model gives consistent results with the SM predictions and existing experimental data on the behavior of

\begin{document}$ DBR(q^2)$\end{document}

with respect to

\begin{document}$ q^2 $\end{document}

. As far as the

\begin{document}$ q^2 $\end{document}

behavior of the

\begin{document}$ A_{FB}(q^2) $\end{document}

is concerned, the two types of fits in leptoquark model for

\begin{document}$ \tau $\end{document}

and the predictions of this model at

\begin{document}$ \mu $\end{document}

channel give exactly the same results as the SM. We also investigate the behavior of the parameter

\begin{document}$ R(q^2) $\end{document}

with respect to

\begin{document}$ q^2 $\end{document}

and the value of

\begin{document}$ R(\Lambda_c) $\end{document}

both in vector leptoquark and SM models. Both types fit solutions lead to results that deviate considerably from the SM predictions on

\begin{document}$R(q^2)- q^2 $\end{document}

as well as

\begin{document}$ R(\Lambda_c) $\end{document}

. Future experimental data on

\begin{document}$R(q^2)- q^2 $\end{document}

as well as

\begin{document}$ R(\Lambda_c) $\end{document}

, which would be available after measurements on

\begin{document}$ \Lambda_b \rightarrow \Lambda_c \tau ~ \overline{\nu}_\tau$\end{document}

channel, will be very helpful. Any experimental deviations from the SM predictions in this channel will strengthen the importance of the tree-level hadronic weak transitions as good probes of the new physics effects beyond the SM (BSM).

On-shell mediator dark matter models and the Xenon1T excess

Mingxuan Du, Jinhan Liang, Zuowei Liu, Van Que Tran, Yilun Xue

Published:

Abstract:
We present a dark matter model to explain the excess events in the electron recoil data recently reported by the Xenon1T experiment. In our model, dark matter

\begin{document}$\chi$\end{document}

annihilates into a pair of on-shell particles

\begin{document}$\phi$\end{document}

which subsequently decay into

\begin{document}$\psi \psi$\end{document}

final state;

\begin{document}$\psi$\end{document}

interacts with electron to generate the observed excess events. Due to the mass hierarchy, the velocity of

\begin{document}$\psi$\end{document}

can be rather large and can have an extended distribution, which provides a good fit to the electron recoil energy spectrum. We estimated the flux of

\begin{document}$\psi$\end{document}

from dark matter annihilations in the galaxy and further determined the interaction cross section which is sizable but small enough to allow

\begin{document}$\psi$\end{document}

to penetrate the rocks to reach the underground labs.

Microscopic states of Kerr black holes from boundary-bulk correspondence

Jing-Bo Wang

Published:

Abstract:
It was claimed by the author that black holes can be considered as topological insulators. They both have boundary modes and those boundary modes can be described by an effective BF theory. In this paper, we analyze the boundary modes on the horizon of black holes with the methods developed for topological insulators. Firstly the BTZ black hole is analysed, and the results are compatible with the previous works. Then we generalize those results to Kerr black holes. Some new results are obtained: dimensionless right- and left-temperature can be defined and have well behaviors both in Schwarzschild limit

\begin{document}$a\rightarrow 0$\end{document}

and in extremal limit

\begin{document}$a\rightarrow M$\end{document}

. Upon the Kerr/CFT correspondence, we can associate a central charge

\begin{document}$c=12 M r_+$\end{document}

with an arbitrary Kerr black hole. We can identify the microstates of the Kerr black hole with the quantum states of this scalar field. From this identification we can count the number of microstates of the Kerr black hole and give the Bekenstein-Hawking area law for the entropy.

Deuteron Inelastic Scattering on the ⁶Li and ⁷Li nuclei within the Three-Body Cluster Model

M. V. EGOROV, V. I. POSTNIKOV

Published:

Abstract:
The problem of the deuteron interaction with lithium nuclei which treated as the systems of two coupled pointlike clusters is formulated to calculate d+Li reaction's cross sections. The d+Li reaction mechanism is described using the Faddeev theory for the three-body problem of deuteron-nucleus interaction. This theory is slightly extended for calculation of as stripping processes ⁶Li(d,p)⁷Li, ⁷Li(d,p)⁸Li, ⁶Li(d,n)⁷Be and ⁷Li(d,n)⁸Be well as fragmentation reactions yielding tritium,

\begin{document}$\alpha$\end{document}

-particles, and continuous neutrons and protons in the initial deuteron kinetic-energy region

\begin{document}$E_d=0.5-20$\end{document}

MeV. The phase shifts found for

\begin{document}$d+^6$\end{document}

Li and

\begin{document}$d+^7$\end{document}

Li elastic scattering, as part of the simple optic model with a complex central potential, were used to find the cross sections for the ⁶Li

\begin{document}$(d,\gamma_{M1})^8{\rm{Be}}$\end{document}

and ⁷Li

\begin{document}$(d,\gamma_{E1})^9{\rm{Be}}$\end{document}

radiation captures. The three-body dynamics role is also summarized to demonstrate its significant influence within

\begin{document}$d+^7$\end{document}

Li system.

Possible Light Neutral Boson and Particle Mass Quantization

Tao-Feng Wang, Zi-Ming Li, Xiao-Ting Yang

Published:

Abstract:
Qualities of nucleons, such as the fundamental parameter mass, in extreme conditions might be modified relative to the isolate ones. We show the ratio of the EMC-effect tagged nucleon mass to that of the free one (

\begin{document}$m^{\ast}/m$\end{document}

), which are derived from nuclear structure function ratio between heavy nuclei and deuterium measured in electron Deep Inelastic Scattering (DIS) reaction in 0.3

\begin{document}$\leqslant x\leqslant $\end{document}

0.7. The increase of

\begin{document}$m^{\ast}/m$\end{document}

with

\begin{document}$A^{-1/3}$\end{document}

is phenomenological interpreted via the release of color-singlet cluster formed by sea quarks and gluons in bound nucleons holding high momentum in the nucleus, from which the mass and fraction of non-nucleonic components in nuclei are deduced. The mass of color-singlet cluster released from per short range correlated (SRC) proton in high momentum region (

\begin{document}$k>$\end{document}

2 fm

\begin{document}$^{-1}$\end{document}

) is extracted to be 16.890

\begin{document}$\pm$\end{document}

0.016 MeV/c

\begin{document}$^{2}$\end{document}

, which is an evidence of the possible indication of a light neutral boson and quantized mass of matter.

Holographic Schwinger effect in a soft wall AdS/QCD model

Yue Ding, Zi-qiang Zhang

Published:

Abstract:
We perform the potential analysis for the holographic Schwinger effect in a deformed

\begin{document}$ AdS_5 $\end{document}

model with conformal invariance broken by a background dilaton. We evaluate the static potential by analyzing the classical action of a string attaching the rectangular Wilson loop on a probe D3 brane sitting at an intermediate position in the bulk AdS space. We observe that the inclusion of chemical potential tends to enhance the production rate, reverse to the effect of confining scale. Also, we calculate the critical electric field by Dirac-Born-Infeld (DBI) action.

Asymptotic structure of Einstein-Gauss-Bonnet theory in lower dimensions

H. Lü, Pujian Mao

Published:

Abstract:
Recently, an action principle for the

\begin{document}$D\rightarrow4$\end{document}

limit of the Einstein-Gauss-Bonnet gravity has been proposed. It is a special scalar-tensor theory that belongs to the family of Horndeski gravity. It also has a well defined

\begin{document}$D\rightarrow3$\end{document}

and

\begin{document}$D\rightarrow2$\end{document}

limit. In this work, we examine this theory in three and four dimensions in Bondi-Sachs framework. In both three and four dimensions, we find that there is no news function associated to the scalar field, which means that there is no scalar propagating degree of freedom in the theory. In four dimensions, the mass-loss formula is not affected by the Gauss-Bonnet term. This is consistent with the fact that there is no scalar radiation. However, the effects of the Gauss-Bonnet term are quite significant in the sense that they arise just one order after the integration constants and also arise in the quadrupole of the gravitational source.

Strangeonium-like hybrids on the lattice

Yunheng Ma, Ying Chen, Ming Gong, Zhaofeng Liu

Published:

Abstract:
The strangeonium-like

\begin{document}$s\bar{s}g$\end{document}

hybrids are investigated from lattice QCD in the quenched approximation. In the Coulomb gauge, spatially extended operators are constructed for

\begin{document}$1^{--}$\end{document}

and

\begin{document}$(0,1,2)^{-+}$\end{document}

states with the color octet

\begin{document}$s\bar{s}$\end{document}

component being separated from the chromomagnetic field strength by spatial distances

\begin{document}$r$\end{document}

, whose matrix elements between the vacuum and the corresponding states are interpreted as Bethe-Salpeter (BS) wave functions. In each of the

\begin{document}$(1,2)^{-+}$\end{document}

channels, the masses and the BS wave functions are reliably derived. The

\begin{document}$1^{-+}$\end{document}

ground state mass is around 2.1-2.2 GeV, and that of

\begin{document}$2^{-+}$\end{document}

is around 2.3-2.4 GeV, while the masses of the first excited states are roughly 1.4 GeV higher. This mass splitting is much larger than the expectation of the phenomenological flux-tube model or constituent gluon model for hybrids, which is usually a few hundred MeV. The BS wave functions with respect to

\begin{document}$r$\end{document}

show clear radial nodal structures of non-relativistic two-body system, which imply that

\begin{document}$r$\end{document}

is a meaningful dynamical variable for these hybrids and motivate a color halo picture of hybrids that the color octet

\begin{document}$s\bar{s}$\end{document}

is surrounded by gluonic degrees of freedom. In the

\begin{document}$1^{--}$\end{document}

channel, the properties of the lowest two states comply with those of

\begin{document}$\phi(1020)$\end{document}

and

\begin{document}$\phi(1680)$\end{document}

. We have not obtained convincing information relevant to

\begin{document}$\phi(2170)$\end{document}

yet, however, we argue that whether

\begin{document}$\phi(2170)$\end{document}

is a conventional

\begin{document}$s\bar{s}$\end{document}

meson or a

\begin{document}$s\bar{s}g$\end{document}

hybrid within the color halo scenario, the ratio of partial decay widths

\begin{document}$\Gamma(\phi \eta)$\end{document}

and

\begin{document}$\Gamma (\phi \eta')$\end{document}

observed by BESIII can be understood by the mechanism of hadronic transition of a strangeonium-like meson along with the

\begin{document}$\eta-\eta'$\end{document}

mixing.

Search For Electron-Antineutrinos Associated With Gravitational-Wave Events GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817 at Daya Bay

F. P. An, A. B. Balantekin, H. R. Band, M. Bishai, S. Blyth, G. F. Cao, J. Cao, J. F. Chang, Y. Chang, H. S. Chen, S. M. Chen, Y. Chen, Y. X. Chen, J. Cheng, Z. K. Cheng, J. J. Cherwinka, M. C. Chu, J. P. Cummings, O. Dalager, F. S. Deng, Y. Y. Ding, M. V. Diwan, T. Dohnal, J. Dove, M. Dvořák, D. A. Dwyer, J. P. Gallo, M. Gonchar, G. H. Gong, H. Gong, W. Q. Gu, J. Y. Guo, L. Guo, X. H. Guo, Y. H. Guo, Z. Guo, R. W. Hackenburg, S. Hans, M. He, K. M. Heeger, Y. K. Heng, A. Higuera, Y. K. Hor, Y. B. Hsiung, B. Z. Hu, J. R. Hu, T. Hu, Z. J. Hu, H. X. Huang, X. T. Huang, Y. B. Huang, P. Huber, D. E. Jaffe, K. L. Jen, X. L. Ji, X. P. Ji, R. A. Johnson, D. Jones, L. Kang, S. H. Kettell, S. Kohn, M. Kramer, T. J. Langford, J. Lee, J. H. C. Lee, R. T. Lei, R. Leitner, J. K. C. Leung, F. Li, J. J. Li, Q. J. Li, S. Li, S. C. Li, W. D. Li, X. N. Li, X. Q. Li, Y. F. Li, Z. B. Li, H. Liang, C. J. Lin, G. L. Lin, S. Lin, J. J. Ling, J. M. Link, L. Littenberg, B. R. Littlejohn, J. C. Liu, J. L. Liu, C. Lu, H. Q. Lu, J. S.

Published:

Abstract:
Abstract: Providing a possible connection between neutrino emission and gravitational-wave (GW) bursts is im- portant to our understanding of the physical processes that occur when black holes or neutron stars merge. In the Daya Bay experiment, using the data collected from December 2011 to August 2017, a search has been performed for electron-antineutrino signals coinciding with detected GW events, including GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817. We used three time windows of ±10 s, ±500 s, and ±1000 s relative to the occurrence of the GW events, and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates. The detected electron-antineutrino candidates are consistent with the expected background rates for all the three time windows. Assuming monochromatic spectra, we found upper limits (90% confidence level) on electron-antineutrino fluence of (1.13 − 2.44)×10¹¹ cm⁻² at 5 MeV to 8.0×107 cm⁻² at 100 MeV for the three time windows. Under the assumption of a Fermi-Dirac spectrum, the upper limits were found to be (5.4 − 7.0)×10⁹ cm⁻² for the three time windows.

Top Rare Decays t→cV in the Mirror Twin Higgs Models

Su-Ya Bie, Guo-Li Liu, Wenyu Wang

Published:

Abstract:
The decay

\begin{document}$t \to c V $\end{document}

(

\begin{document}$V=\gamma,~Z,~g$\end{document}

) process in the mirror twin Higgs models with the colorless top partners are studied in this paper. We found that the branching ratios of these decays can in some parameter spaces alter the standard model expectations greatly and may be detectable according to the currently precision electroweak measurements. Thus, the constraints on the model parameters may be obtained from the branching fraction of the decay processes, which may serve as a robust detection to this new physics model.

A new measure of thermal micro-behavior for the AdS black hole

Zhen-Ming Xu, Bin Wu, Tao Yang, Wen-Li Yang

Published:

Abstract:
Inspired by the hypothesis of the black hole molecule, with the help of the Hawking temperature, entropy and the thermodynamics curvature of the black hole, we propose a new measure of the relation between the interaction and the thermal motion of molecules of the AdS black hole as a preliminary and coarse-grained description. The measure enables us to introduce a dimensionless ratio to characterize this relation and show that there is indeed competition between the interaction among black hole molecules and their thermal motion. For the charged AdS black hole, below the critical dimensionless pressure, there are three transitions between the interaction state and the thermal motion state. While above the critical dimensionless pressure, there is only one transition. For the Schwarzschild-AdS black hole and five-dimensional Gauss-Bonnet AdS black hole, there is always a transition between the interaction state and the thermal motion state.

Feasibility and physics potential of detecting ⁸B solar neutrinos at JUNO

Angel Abusleme, Thomas Adam, Shakeel Ahmad, Sebastiano Aiello, Nawab Ali, Fengpeng An, Guangpeng An, Qi An, Giuseppe Andronico, Nikolay Anfimov, Vito Antonelli, Tatiana Antoshkina, Burin Asavapibhop, João Pedro Athayde Marcondes de André, Andrej Babic, Wander Baldini, Marica Baldoncini, Andrea Barresi, Eric Baussan, Marco Bellato, Enrico Bernieri, David Biare, Thilo Birkenfeld, Sylvie Blin, David Blum, Simon Blyth, Clément Bordereau, Augusto Brigatti, Riccardo Brugnera, Antonio Budano, Pit Burgbacher, Mario Buscemi, Severino Bussino, Jose Busto, Ilya Butorov, Anatael Cabrera, Hao Cai, Xiao Cai, Yanke Cai, Zhiyan Cai, Antonio Cammi, Agustin Campeny, Chuanya Cao, Guofu Cao, Jun Cao, Rossella Caruso, Cédric Cerna, Irakli Chakaberia, Jinfan Chang, Yun Chang, Pingping Chen, Po-An Chen, Shaomin Chen, Shenjian Chen, Xurong Chen, Yi-Wen Chen, Yixue Chen, Yu Chen, Zhang Chen, Jie Cheng, Yaping Cheng, Alexander Chepurnov, Fabrizio Chiarello, Davide Chiesa, Pietro Chimenti, Artem Chukanov, Anna Chuvashova, Catia Cle

Published:

Abstract:
The Jiangmen Underground Neutrino Observatory (JUNO) features a 20 kt multi-purpose underground liquid scintillator sphere as its main detector. Some of JUNO's features make it an excellent experiment for

\begin{document}$ ^8 $\end{document}

B solar neutrino measurements, such as its low-energy threshold, its high energy resolution compared to water Cherenkov detectors, and its much larger target mass compared to previous liquid scintillator detectors. In this paper we present a comprehensive assessment of JUNO's potential for detecting

\begin{document}$ ^8 $\end{document}

B solar neutrinos via the neutrino-electron elastic scattering process. A reduced 2 MeV threshold on the recoil electron energy is found to be achievable assuming the intrinsic radioactive background

\begin{document}$ ^{238} $\end{document}

U and

\begin{document}$ ^{232} $\end{document}

Th in the liquid scintillator can be controlled to 10

\begin{document}$ ^{-17} $\end{document}

g/g. With ten years of data taking, about 60,000 signal and 30,000 background events are expected. This large sample will enable an examination of the distortion of the recoil electron spectrum that is dominated by the neutrino flavor transformation in the dense solar matter, which will shed new light on the inconsistency between the measured electron spectra and the predictions of the standard three-flavor neutrino oscillation framework. If

\begin{document}$ \Delta m^{2}_{21} = 4.8\times10^{-5}\; (7.5\times10^{-5}) $\end{document}

eV

\begin{document}$ ^{2} $\end{document}

, JUNO can provide evidence of neutrino oscillation in the Earth at the about 3

\begin{document}$ \sigma $\end{document}

(2

\begin{document}$ \sigma $\end{document}

) level by measuring the non-zero signal rate variation with respect to the solar zenith angle. Moreover, JUNO can simultaneously measure

\begin{document}$ \Delta m^2_{21} $\end{document}

using

\begin{document}$ ^8 $\end{document}

B solar neutrinos to a precision of 20% or better depending on the central value and to sub-percent precision using reactor antineutrinos. A comparison of these two measurements from the same detector will help understand the current mild inconsistency between the value of

\begin{document}$ \Delta m^2_{21} $\end{document}

reported by solar neutrino experiments and the KamLAND experiment.

What can a heavy $U(1)_{B-L} \; Z^\prime$ boson do to the muon $\left(g-2\right)_\mu$ anomaly and to a new Higgs boson mass?

António P. Morais, Roman Pasechnik, J. Pedro Rodrigues

Published:

Abstract:
The minimal

\begin{document}$ {\rm{U}}(1)_{\rm{{B-L}}} $\end{document}

extension of the Standard Model (B-L-SM) offers an explanation for neutrino mass generation via a seesaw mechanism as well as contains two new physics states such as an extra Higgs boson and a new

\begin{document}$ Z' $\end{document}

gauge boson. The emergence of a second Higgs particle as well as a new

\begin{document}$ Z^\prime $\end{document}

gauge boson, both linked to the breaking of a local

\begin{document}$ {\rm{U}}(1)_{\rm{{B-L}}} $\end{document}

symmetry, makes the B-L-SM rather constrained by direct searches at the Large Hadron Collider (LHC) experiments. We investigate the phenomenological status of the B-L-SM by confronting the new physics predictions with the LHC and electroweak precision data. Taking into account the current bounds from direct LHC searches, we demonstrate that the prediction for the muon

\begin{document}$ \left(g-2\right)_\mu $\end{document}

anomaly in the B-L-SM yields at most a contribution of approximately

\begin{document}$ 8.9 \times 10^{-12} $\end{document}

which represents a tension of

\begin{document}$ 3.28 $\end{document}

standard deviations, with the current

\begin{document}$ 1\sigma $\end{document}

uncertainty, by means of a

\begin{document}$ Z^\prime $\end{document}

boson if its mass lies in a range of

\begin{document}$ 6.3 $\end{document}

to

\begin{document}$ 6.5\; {\rm{TeV}} $\end{document}

, within the reach of future LHC runs. This means that the B-L-SM, with heavy yet allowed

\begin{document}$ Z^\prime $\end{document}

boson mass range, in practice does not resolve the tension between the observed anomaly in the muon

\begin{document}$ \left(g-2\right)_\mu $\end{document}

and the theoretical prediction in the Standard Model. Such a heavy

\begin{document}$ Z^\prime $\end{document}

boson also implies that the minimal value for a new Higgs mass is of the order of 400 GeV.

Isospin dependence of the nuclear binding energy

Y. Q. He, J. K. Ge, G. J. Fu, H. Jiang

Published:

Abstract:
In this paper we study the symmetry energy and the Wigner energy in the binding energy formula for atomic nuclei. We extract simultaneously the

\begin{document}$I^2$\end{document}

symmetry energy and Wigner energy coefficients by using the double difference of "experimental" symmetry-Wigner energies, based on the binding energy data of nuclei with

\begin{document}$A \geq 16$\end{document}

. Our study of the triple difference formula and the "experimental" symmetry-Wigner energy suggests that the macroscopic isospin dependence of binding energies is well explained by the

\begin{document}$I^{2}$\end{document}

symmetry energy and the Wigner energy, and further considering the

\begin{document}$I^{4}$\end{document}

term in the binding energy formula does not substantially improve the calculation result.

Thin Accretion Disk around a four-dimensional Einstein-Gauss-Bonnet Black Hole

Cheng Liu, Tao Zhu, Qiang Wu

Published:

Abstract:
Recently a novel four-dimensional Einstein-Gauss-Bonnet (4EGB) theory of gravity was proposed by Glavan and Lin [D. Glavan and C. Lin, Phys. Rev. Lett. 124, 081301 (2020)] which includes a regularized Gauss-Bonnet term by using the re-scalaring of the Gauss-Bonnet coupling constant

\begin{document}$\alpha \to \alpha/(D-4)$\end{document}

in the limit

\begin{document}$D\to 4$\end{document}

. This theory also has been reformulated to a specific class of the Horndeski theory with an additional scalar degree of freedom and to a spatial covariant version with a Lagrangian multiplier which can eliminate the scalar mode. Here we study the physical properties of the electromagnetic radiation emitted from a thin accretion disk around the static spherically symmetric black hole in the 4EGB gravity. For this purpose, we assume the disk is in a steady-state and in hydrodynamic and thermodynamic equilibrium so that the emitted electromagnetic radiation is a black body spectrum. We study in detail the effects of the Gauss-Bonnet coupling constant

\begin{document}$\alpha$\end{document}

in 4EGB gravity on the energy flux, temperature distribution, and electromagnetic spectrum of the disk. It is shown that with the increases of the parameter

\begin{document}$\alpha$\end{document}

, the energy flux, temperature distribution, and electromagnetic spectrum of the accretion disk all increases. Besides, we also show that the accretion efficiency increases as the growth of the parameter

\begin{document}$\alpha$\end{document}

. Our results indicate that the thin accretion disk around the static spherically symmetric black hole in the 4EGB gravity is hotter, more luminosity, and more efficient than that around a Schwarzschild black hole with the same mass for a positive

\begin{document}$\alpha$\end{document}

, while it is cooler, less luminosity, and less efficient for a negative

\begin{document}$\alpha$\end{document}

.

Isgur-Wise function in B_c decays to charmonium with the Bethe-Salpeter method

Zi-Kan Geng, Yue Jiang, Tianhong Wang, Hui-Wen Zheng, Guo-Li Wang

Published:

Abstract:
The heavy quark effective theory vastly reduces the weak-decay form factors of hadrons containing one heavy quark. Many works attempt to apply this theory to the multiple heavy quarks hadrons directly. In this paper, we examine this confusing application by the instantaneous Bethe-Salpeter method from phenomenological respect, and give the numerical results for the

\begin{document}$B_c$\end{document}

decays to charmonium where the final states including

\begin{document}$1S$\end{document}

,

\begin{document}$1P$\end{document}

,

\begin{document}$2S$\end{document}

and

\begin{document}$2P$\end{document}

. Our results indicate that the form factors parameterized by a single Isgur-Wise function deviate seriously from the full ones, especially involving the excited states. The relativistic corrections (

\begin{document}$1/m_Q$\end{document}

corrections) require the introduction of more non-perturbative universal functions, similarly to the Isgur-Wise function, which are the overlapping integrals of the wave functions with the relative momentum between the quark and antiquark.

Analysis of the 1S and 2S states of the Λ_Q and Ξ_Q with the QCD

Zhi-Gang Wang, Hui-Juan Wang

Published:

Abstract:
In this article, we study the ground states and the first radial excited states of the flavor antitriplet heavy baryon states

\begin{document}$\Lambda_Q$\end{document}

and

\begin{document}$\Xi_Q$\end{document}

with the spin-parity

\begin{document}$J^P={1\over 2}^{+}$\end{document}

by carrying out the operator product expansion up to the vacuum condensates of dimension

\begin{document}$10$\end{document}

in a consistent way. We observe that the higher dimensional vacuum condensates play an important role, and obtain very stable QCD sum rules with variations of the Borel parameters for the heavy baryon states for the first time. The predicted masses

\begin{document}$6.08\pm0.09\,{\rm{GeV}}$\end{document}

,

\begin{document}$2.78\pm0.08\,{\rm{GeV}}$\end{document}

and

\begin{document}$2.96\pm0.09\,{\rm{GeV}}$\end{document}

for the first radial excited states

\begin{document}$\Lambda_b(2{\rm{S}})$\end{document}

,

\begin{document}$\Lambda_c(2{\rm{S}})$\end{document}

and

\begin{document}$\Xi_c(2{\rm{S}})$\end{document}

respectively are in excellent agreement with the experimental data and support assigning the

\begin{document}$\Lambda_b(6072)$\end{document}

,

\begin{document}$\Lambda_c(2765)$\end{document}

and

\begin{document}$\Xi_c(2980/2970)$\end{document}

to be the first radial excited states of the

\begin{document}$\Lambda_b$\end{document}

,

\begin{document}$\Lambda_c$\end{document}

and

\begin{document}$\Xi_c$\end{document}

, respectively, the predicted mass

\begin{document}$6.24\pm0.07\,{\rm{GeV}}$\end{document}

for the

\begin{document}$\Xi_b(2{\rm{S}})$\end{document}

can be confronted to the experimental data in the future.

Flat limit of the de Sitter QFT in the rest frame vacuum

Ion I. Cotăescu

Published:

Abstract:
The problem of the flat limits of the scalar and spinor fields on the de Sitter expanding universe is considered in the traditional adiabatic vacuum and in the new rest frame vacuum we proposed recently where the frequencies are separated in the rest frames as in special relativity. It is shown that only in the rest frame vacuum the Minkowskian flat limit can be reached naturally for any momenta while in the adiabatic vacuum this limit remains undefined in the rest frames where the momentum vanishes. An important role is played by the phases of the fundamental solutions in the rest frame vacuum which must be regularized in order to obtain the desired Minkowskian flat limits. This procedure fixes the phases of the scalar mode functions and Dirac spinors leading to their definitive expressions derived here. The physical consequence is that in the rest frame vacuum the flat limits of the one-particle operators are just the corresponding operators of special relativity.

Dispersive Analysis of Low Energy γN→πN Process and Studies on the N*(890) Resonance

Yao Ma, Wen-Qi Niu, De-Liang Yao, Han-Qing Zheng

Published:

Abstract:
We present a dispersive representation of the

\begin{document}$ \gamma N\rightarrow \pi N $\end{document}

partial-wave amplitude based on unitarity and analyticity. In this representation, the right-hand-cut contribution responsible for

\begin{document}$ \pi N $\end{document}

final-state-interaction effects are taken into account via an Omnés formalism with elastic

\begin{document}$ \pi N $\end{document}

phase shifts as inputs, while the left-hand-cut contribution is estimated by invoking chiral perturbation theory. Numerical fits are performed in order to pin down the involved subtraction constants. It is found that good fit quality can be achieved with only one free parameter and the experimental data of the multipole amplitude

\begin{document}$ E_{0}^+ $\end{document}

in the energy region below the

\begin{document}$ \Delta(1232) $\end{document}

are well described. Furthermore, we extend the

\begin{document}$ \gamma N\rightarrow \pi N $\end{document}

partial-wave amplitude to the second Riemann sheet so as to extract the couplings of the

\begin{document}$ N^\ast(890) $\end{document}

. The modulus of the residue of the multipole amplitude

\begin{document}$ E_{0}^+ $\end{document}

(

\begin{document}$ {\rm S_{11}pE} $\end{document}

) is

\begin{document}$ 2.41\rm{mfm\cdot GeV^2} $\end{document}

and the partial width of

\begin{document}$ N^*(890)\to\gamma N $\end{document}

at the pole is about

\begin{document}$ 0.369\ {\rm MeV} $\end{document}

, which is almost the same as the one of the

\begin{document}$ N^*(1535) $\end{document}

resonance, indicating that

\begin{document}$ N^\ast(890) $\end{document}

strongly couples to

\begin{document}$ \pi N $\end{document}

system.

Relic Density of Asymmetric Dark Matter with Sommerfeld enhancement

Aihemaitijiang Abudurusuli, Hoernisa Iminniyaz

Published:

Abstract:
We investigate the evolution of abundance of the asymmetric thermal Dark Matter when its annihilation rate at chemical decoupling is boosted by the Sommerfeld enhancement. Then we discuss the effect of kinetic decoupling on relic abundance of asymmetric Dark Matter when the interaction rate depends on the velocity. Usually the relic density of asymmetric Dark Matter is analyzed in the frame of chemical decoupling. Indeed after decoupling from the chemical equilibrium, asymmetric Dark Matter particles and anti--particles were still in kinetic equilibrium for a while. It has no effect on the case of s−wave annihilation since there is no temperature dependence in this case. However, the kinetic decoupling has impacts for the case of p−wave annihilation and Sommerfeld enhanced s− and p−wave annihilations. We investigate in which extent the kinetic decoupling affects the relic abundances of asymmetric Dark Matter particle and anti--particle in detail. We found the constraints on the cross section and asymmetry factor by using the observational data of relic density of Dark Matter.

Bulk viscosity for interacting strange quark matter and r-mode instability windows for strange stars

Jian-Feng Xu, Dong-Biao Kang, Guang-Xiong Peng, Cheng-Jun Xia

Published:

Abstract:
We investigate the bulk viscosity of strange quark matter in the framework of equivparticle model, where analytical formulae are obtained for certain temperature ranges and can be readily applied to those with various quark mass scalings. In the case of adopting a quark mass scaling with both linear confinement and perturbative interactions, the obtained bulk viscosity increases by

\begin{document}$1 \sim 2$\end{document}

orders of magnitude comparing with bag model scenarios. Such an enhancement is mainly due to the large quark equivalent masses adopted in the equivparticle model, which essentially attribute to the strong interquark interactions and are related to the dynamical chiral symmetry breaking. Due to the large bulk viscosity, the predicted damping time of oscillations for canonical 1.4

\begin{document}${\rm{M}}_\odot$\end{document}

strange star is less than one millisecond, which is faster than previous findings. Consequently, the obtained

\begin{document}$r$\end{document}

-mode instability window for the canonical strange stars well accommodates the observational frequencies and temperatures for pulsars in the low-mass X-ray binaries (LMXBs).

Expansion of EYM Amplitudes in Gauge Invariant Vector Space

Bo Feng, Xiao-Di Li, Rijun Huang

Published:

Abstract:
Motivated by the problem of expanding single-trace tree-level amplitude of Einstein-YangMills theory to the BCJ basis of Yang-Mills amplitudes, we present an alternative expansion formula in the gauge invariant vector space. Starting from a generic vector space consisting of polynomials of momenta and polarization vectors, we define a new sub-space as gauge invariant vector space by imposing constraints of gauge invariant conditions. To characterize this sub-space, we compute its dimension and construct an explicit gauge invariant basis from it. We propose an expansion formula in the gauge invariant basis with expansion coefficients being linear combinations of Yang-Mills amplitude, manifesting the gauge invariance of both expansion basis and coefficients. With help of quivers, we compute the expansion coefficients via differential operators and demonstrate the general expansion algorithm by several examples.

Redshift drift in uniformly accelerated reference frame

Zhe Chang, Qing-Hua Zhu

Published: , doi: 10.1088/1674-1137/44/5/055101

Abstract:
We construct an alternative uniformly accelerated reference frame based on 3+1 formalism in adapted coordinate. It is distinguished with Rindler coordinate that there is time-dependent redshift drift between co-moving observers. The experimentally falsifiable distinguishment might promote our understanding of non-inertial frame in laboratory.

Just Accepted