Chinese Physics C

A unique gravitational wave signal from phase transition during inflation

Haipeng An, Kun-Feng Lyu, Lian-Tao Wang, Siyi Zhou

2022, 46(10): 101001. doi: 10.1088/1674-1137/ac76a7

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Abstract:
We study the properties of gravitational wave (GW) signals produced by first-order phase transitions during the inflation era. We show that the power spectrum of a GW oscillates with its wave number. This signal can be observed directly by future terrestrial and spatial GW detectors and through the B-mode spectrum in the CMB. This oscillatory feature of the GW is generic for any approximately instantaneous sources occurring during inflation and is distinct from the GW from phase transitions after inflation. The details of the GW spectrum contain information about the scale of the phase transition and the later evolution of the universe.

Study of background from accidental coincidence signalsin the PandaX-II experiment

Abdusalam Abdukerim, Wei Chen, Xun Chen, Yunhua Chen, Chen Cheng, Xiangyi Cui, Yingjie Fan, Deqing Fang, Changbo Fu, Mengting Fu, Lisheng Geng, Karl Giboni, Linhui Gu, Xuyuan Guo, Ke Han, Changda He, Di Huang, Yan Huang, Yanlin Huang, Zhou Huang, Xiangdong Ji, Yonglin Ju, Shuaijie Li, Huaxuan Liu, Jianglai Liu, Wenbo Ma, Yugang Ma, Yajun Mao, Yue Meng, Kaixiang Ni, Jinhua Ning, Xuyang Ning, Xiangxiang Ren, Changsong Shang, Lin Si, Guofang Shen, Andi Tan, Anqing Wang, Hongwei Wang, Meng Wang, Qiuhong Wang, Siguang Wang, Wei Wang, Xiuli Wang, Zhou Wang, Mengmeng Wu, Shiyong Wu, Weihao Wu, Jingkai Xia, Mengjiao Xiao, Pengwei Xie, Binbin Yan, Jijun Yang, Yong Yang, Chunxu Yu, Jumin Yuan, Ying Yuan, Xinning Zeng, Dan Zhang, Tao Zhang, Li Zhao, Qibin Zheng, Jifang Zhou, Ning Zhou, Xiaopeng Zhou, (PandaX-II Collaboration)

2022, 46(10): 103001. doi: 10.1088/1674-1137/ac7cd8

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Lepton and quark mixing patterns with generalized CP transformations

Joy Ganguly, Raghavendra Srikanth Hundi

2022, 46(10): 103101. doi: 10.1088/1674-1137/ac763c

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Abstract:
In this study, we modify a scenario, originally proposed by Grimus and Lavoura, in order to obtain maximal values for the atmospheric mixing angle and

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

, violating the Dirac phase of the lepton sector. To achieve this, we employ

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

and some discrete symmetries in a type II seesaw model. To make predictions about the neutrino mass ordering and smallness of the reactor angle, we establish some conditions on the elements of the neutrino mass matrix of our model. Finally, we study the quark masses and mixing pattern within the framework of our model.

Spectroscopic study of strangeness = –3 Ω^– baryon

Chandni Menapara, Ajay Kumar Rai

2022, 46(10): 103102. doi: 10.1088/1674-1137/ac78d1

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Abstract:

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

baryon with sss quarks has been investigated through many theoretical studies so far but scarcely observed in experiments. Here, an attempt has been made to explore properties of Ω with hypercentral Constituent Quark Model (hCQM) with a linear confining term. The resonance mass spectra have been obtained for 1S–4S, 1P–4P, 1D–3D, and 1F–2F. The Regge trajectory has been investigated for the linear nature based on calculated data along with the magnetic moment. The present work has been compared with various approaches and known experimental findings.

Search for single production of vectorlike B-quarks at the LHC

Jin-Zhong Han, Yao-Bei Liu, Lu Xing, Shuai Xu

2022, 46(10): 103103. doi: 10.1088/1674-1137/ac79ab

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Abstract:
New vectorlike quarks have been proposed in many scenarios of new physics beyond the Standard Model, which address the hierarchy problem and may be potentially discovered at the Large Hadron Collider (LHC). Based on a model-independent framework, we propose to search for the vectorlike B-quark (VLQ-B) and focus on resonant production via b-gluon fusion through chromomagnetic interactions. We then explore the possible signals of the VLQ-B through the

\begin{document}$ B\to tW $\end{document}

decay mode at the 14 TeV LHC. After a rapid simulation of signal and background events, the

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

excluded regions and the

\begin{document}$ 5\sigma $\end{document}

discovery reach in the parameter plane of

\begin{document}$ \kappa_{B}-M_B $\end{document}

are obtained at the LHC with an integrated luminosity of 300 (3000) fb

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

in the dilepton final states.

General one-loop reduction in generalized Feynman parametrization form

Hongbin Wang

2022, 46(10): 103104. doi: 10.1088/1674-1137/ac7a1c

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Abstract:
The search for an effective reduction method is one of the main topics in higher loop computation. Recently, an alternative reduction method was proposed by Chen in [1, 2]. In this paper, we test the power of Chen's new method using one-loop scalar integrals with propagators of higher power. More explicitly, with the improved version of the method, we can cancel the dimension shift and terms with unwanted power shifting. Thus, the obtained integrating-by-parts relations are significantly simpler and can be solved easily. Using this method, we present explicit examples of a bubble, triangle, box, and pentagon with one doubled propagator. With these results, we complete our previous computations in [3] with the missing tadpole coefficients and show the potential of Chen's method for efficient reduction in higher loop integrals.

Joint explanation of W-mass and muon g–2 in the 2HDM

Xiao-Fang Han, Fei Wang, Lei Wang, Jin-Min Yang, Yang Zhang

2022, 46(10): 103105. doi: 10.1088/1674-1137/ac7c63

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Abstract:
Because both W-mass and muon

\begin{document}$ g-2 $\end{document}

can be affected by mass splittings among extra Higgs bosons

\begin{document}$ (H,\; A,\; H^\pm) $\end{document}

in a two-Higgs-doublet model, we take a model with μ-τ lepton flavor violation interactions to examine the two anomalies reported by CDF II and FNAL. We obtain the following observations: (i) Combined with theoretical constraints, the CDF W-mass measurement disfavors H or A degenerating in mass with

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

but allows H and A to degenerate. The mass splitting between

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

and

\begin{document}$ H/A $\end{document}

must be larger than 10 GeV.

\begin{document}$ m_{H^\pm} $\end{document}

and

\begin{document}$ m_{A} $\end{document}

are favored to be smaller than 650 GeV for

\begin{document}$ m_H<120 $\end{document}

GeV and allowed to have larger values with increasing

\begin{document}$ m_H $\end{document}

. (ii) After imposing other relevant experimental constraints, there are parameter spaces that simultaneously satisfy (at the

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

level) the CDF W-mass, FNAL muon

\begin{document}$ g-2 $\end{document}

, and data on lepton universality in τ decays; however, the mass splittings among extra Higgs bosons are strictly constrained.

Decay widths of Z_cs(3985/4000) based on rigorous quark-hadron duality

Zhi-Gang Wang

2022, 46(10): 103106. doi: 10.1088/1674-1137/ac7cd7

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Abstract:
In this study, we explore the hadronic coupling constants

\begin{document}$ G_{ZJ/\psi K} $\end{document}

,

\begin{document}$ G_{Z\eta_c K^*} $\end{document}

, and

\begin{document}$ G_{ZD^* \bar{D}_s} $\end{document}

of the exotic states

\begin{document}$ Z_{cs}(3985/4000) $\end{document}

within the pictures of both the tetraquark and molecular states with the tentative assignments

\begin{document}$ J^{PC}=1^{+-} $\end{document}

based on rigorous quark-hadron duality. Subsequently, we obtain the total widths

\begin{document}$ \Gamma_{Z_{cs}}^T =15.31\pm 2.06\,{\rm{MeV}} $\end{document}

and

\begin{document}$ \Gamma_{Z_{cs}}^M=83.51\pm21.09\,{\rm{MeV}} $\end{document}

, which are consistent with experimental values from the BESIII collaboration,

\begin{document}$ 13.8^{+8.1}_{-5.2}\pm4.9\,{\rm{MeV}} $\end{document}

, and LHCb collaboration,

\begin{document}$ 131 \pm 15 \pm 26\,{\rm{MeV}} $\end{document}

, respectively, and support assigning

\begin{document}$ Z_{cs}(3985) $\end{document}

and

\begin{document}$ Z_{cs}(4000) $\end{document}

as the hidden-charm tetraquark and molecular states with

\begin{document}$ J^{PC}=1^{+-} $\end{document}

, respectively.

Nonextensive effects on QCD chiral phase transition with a chiral chemical potential

Ya-Peng Zhao, Shu-Yu Zuo, Cheng-Ming Li

2022, 46(10): 103107. doi: 10.1088/1674-1137/ac5dbc

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Abstract:
In this study, we investigate the QCD chiral phase diagram in the presence of a chiral chemical potential

\begin{document}$ \mu_{5} $\end{document}

based on nonextensive statistical mechanics. A feature of this new statistic is a dimensionless nonextensivity parameter q, which summarizes all possible effects violating the assumptions of Boltzmann-Gibbs (BG) statistics (when

\begin{document}$ q\rightarrow1 $\end{document}

, it returns to the BG case). Within the nonextensive Polyakov-Nambu-Jona-Lasinio model, we find that as

\begin{document}$ \mu_{5} $\end{document}

increases, the critical end point (CEP) in the

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

plane continues to

\begin{document}$ \mathrm{CEP}_{5} $\end{document}

in the

\begin{document}$ T-\mu_{5} $\end{document}

plane, and nonextensive effects have a significant impact on the evolution from the CEP to

\begin{document}$ \mathrm{CEP}_{5} $\end{document}

. Generally, with an increase in q, both the CEP and

\begin{document}$ \mathrm{CEP}_{5} $\end{document}

move in the direction of a lower temperature T and larger chemical potential μ (

\begin{document}$ \mu_{5} $\end{document}

). In addition, we find that chiral charge density

\begin{document}$ n_{5} $\end{document}

generally increases with T, μ,

\begin{document}$ \mu_{5} $\end{document}

, and q. Our study may provide useful hints about lattice QCD and relativistic heavy-ion collision experiments.

Measuring CP violation in rare W decays at the LHC

Peng-Cheng Lu, Zong-Guo Si, Zhe Wang, Xing-Hua Yang

2022, 46(10): 103108. doi: 10.1088/1674-1137/ac7eb2

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Abstract:
Heavy Majorana neutrinos beyond the standard model can simultaneously explain the origin of tiny neutrino masses and matter-antimatter asymmetry in our Universe. The existence of heavy Majorana neutrinos will also lead to lepton number violation and confirm the possibility of rare lepton-number-violating W decays. With contributions from two different Majorana neutrinos, nonzero CP asymmetry may be generated from the rate difference between W decay and its CP-conjugate process. The aim of this study is to investigate the prospects of measuring CP violation in rare W decays via Majorana neutrinos at the LHC. Our calculations show that the induced CP asymmetry is independent of the Majorana neutrino mass for

\begin{document}$ 15 < {m}_{N}^{} < 70\; {{\rm{GeV}}} $\end{document}

. Such a CP asymmetry, if observed, would in turn provide unambiguous evidence of new physics beyond the standard model.

Studies of the 2α and 3α channels of the ¹²C+¹²C reaction in the range of E_c.m.=8.9 MeV to 21 MeV using the active target Time Projection Chamber

X. Y. Wang, N. T. Zhang, Z. C. Zhang, C. G. Lu, T. L. Pu, J. L. Zhang, L. M. Duan, B. S. Gao, K. A. Li, Y. T. Li, Y. Qian, L. H. Ru, B. Wang, X. D. Xu, H. Y. Zhao, W. P. Lin, Z. W. Cai, B. F. Ji, Q. T. Li, J. Y. Xu, X. D. Tang

2022, 46(10): 104001. doi: 10.1088/1674-1137/ac7a1d

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Abstract:
The ¹²C+¹²C fusion reaction was studied in the range of E_c.m.=8.9 to 21 MeV using the active-target Time Projection Chamber. With full information on all tracks of the reaction products, cross sections of the ¹²C(¹²C,⁸Be)¹⁶O_g.s. channel and the ¹²C(¹²C,3α)¹²C channel could be measured down to the level of a few milibarns. The ¹²C(¹²C,⁸Be)¹⁶O_g.s. reaction channel was determined to be 10

\begin{document}$ _{-8}^{+24} $\end{document}

mb at E_c.m.=11.1 MeV, supporting the direct α transfer reaction mechanism. The ¹²C(¹²C,3α)¹²C reaction channel was studied for the first time using an exclusive measurement. Our result does not confirm the anomaly behavior reported in the previous inclusive measurement by Kolata et al. [Phys. Rev. C 21, 579 (1980)]. Our comparisons with statistical model calculations suggest that the 3α channel is dominated by the fusion evaporation process at E_c.m. > 19 MeV. The additional contribution of the 3α channel increases the fusion reaction cross section by 10% at energies above 20 MeV. We also find that an additional reaction mechanism is needed to explain the measured cross section at E_c.m. < 15 MeV at which point the statistical model prediction vanishes.

Spectral fluctuations in the interacting boson model

Yu-Qing Wu, Wei Teng, Xiao-Jie Hou, Gui-Xiu Na, Yu Zhang, Bing-Cheng He, Yan-An Luo

2022, 46(10): 104101. doi: 10.1088/1674-1137/ac76a5

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Abstract:
The energy dependence of the spectral fluctuations in the interacting boson model (IBM) and its connections to the mean-field structures are analyzed by adopting two statistical measures: the nearest neighbor level spacing distribution

\begin{document}$ P(S)$\end{document}

measuring the chaoticity (regularity) in energy spectra and the

\begin{document}$ \Delta_3(L)$\end{document}

statistics of Dyson and Metha measuring the spectral rigidity. Specifically, the statistical results as functions of the energy cutoff are determined for different dynamical scenarios, including the U(5)-SU(3) and SU(3)-O(6) transitions as well as those near the AW arc of regularity. We observe that most of the changes in spectral fluctuations are triggered near the stationary points of the classical potential, particularly for cases in the deformed region of the IBM phase diagram. Thus, the results justify the stationary point effects from the perspective of statistics. In addition, the approximate degeneracies in the

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

spectrum on the AW arc is also revealed from the statistical calculations.

p_T dispersion of inclusive jets in high-energy nuclear collisions

Shi-Yong Chen, Jun Yan, Wei Dai, Ben-Wei Zhang, En-Ke Wang

2022, 46(10): 104102. doi: 10.1088/1674-1137/ac79aa

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Abstract:
In this study, we investigate the impact of jet quenching on the

\begin{document}$ p_{T} $\end{document}

dispersion (