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The analysis of the excited bottom and bottom strange states B1(5721), $ { B_{2}^{*}(5747) }$, ${ B_{s1}(5830)} $, $ {B_{s2}^{*}(5840) }$, ${ B_{J}(5840) }$ and $ {B_{J}(5970) }$ in B meson family
Guo-Liang YU, Zhi-Gang WANG
Published:   , doi: 10.1088/1674-1137/44/3/033104
In order to make a further confirmation about the assignments of the excited bottom and bottom strange mesons \begin{document}$ B_{1}(5721) $\end{document}, \begin{document}$ B_{2}^{*}(5747) $\end{document}, \begin{document}$ B_{s1}(5830) $\end{document}, \begin{document}$ B_{s2}^{*}(5840) $\end{document} and identify the possible assignments of \begin{document}$ B_{J}(5840) $\end{document}, \begin{document}$ B_{J}(5970) $\end{document}, we study the strong decays of these states with the \begin{document}$ ^{3}P_{0} $\end{document} decay model. Our analysis supports \begin{document}$ B_{1}(5721) $\end{document} and \begin{document}$ B_{2}^{*}(5747) $\end{document} to be the \begin{document}$ 1P_{1}' $\end{document} and \begin{document}$ 1^{3}P_{2} $\end{document} assignments and the \begin{document}$ B_{s1}(5830) $\end{document}, \begin{document}$ B_{s2}^{*}(5840) $\end{document} to be the strange partners of \begin{document}$ B_{1}(5721) $\end{document} and \begin{document}$ B_{2}^{*}(5747) $\end{document}. Besides, we tentatively identify the recently observed \begin{document}$ B_{J}(5840) $\end{document}, \begin{document}$ B_{J}(5970) $\end{document} as the \begin{document}$ 2^{3}S_{1} $\end{document} and \begin{document}$ 1^{3}D_{3} $\end{document} states, respectively. It is noticed that this conclusion needs further confirmation by measuring the decay channels \begin{document}$ B_{J}(5840)\rightarrow B\pi $\end{document} and \begin{document}$ B_{J}(5970)\rightarrow B\pi $\end{document} in experiments.
$ K^* $ production in the $ KN\to K \pi p $ reaction
Shao-Fei Chen, Bo-Chao Liu
Published:   , doi: 10.1088/1674-1137/44/3/034107
In the present work, we investigate the \begin{document}$ K^* $\end{document} production in the \begin{document}$ KN\to K \pi p $\end{document} reaction within an effective Lagrangian approach and isobar model. To describe this reaction, firstly we take into account the contributions from the \begin{document}$ \pi $\end{document}, \begin{document}$ \rho $\end{document} and \begin{document}$ \omega $\end{document} exchanges as in previous studies. We find that, although the data can be described in general, there are some obvious discrepancies between the model and the experimental data. To improve the model, we further consider the contributions of the axial-vector meson and hyperon exchanges. It is shown that the inclusion of a significant contribution of the axial-vector meson exchange in the model can significantly improve the results. This may indicate a large coupling of the axial-vector meson, e.g. the \begin{document}$ a_1(1260) $\end{document}, with the \begin{document}$ KK^* $\end{document} channel. To verify our model, the measurements of the angular distribution and spin density matrix elements of the \begin{document}$ K^{*0} $\end{document} in the \begin{document}$ K_L p\to K^{*0} p $\end{document} reaction will be helpful. Therefore, we make predictions for this reaction for future comparisons.
Extended projection method for massive fermion
Yefan Wang, Zhao Li
Published:   , doi: 10.1088/1674-1137/44/3/033102
Tensor reduction is important for multi-loop amplitude calculation. And the projection method is one of the most popular approaches for tensor reduction. However, projection method could be problematic for amplitude with massive fermions due to the inconsistency between helicity and chirality. We propose an approach to extend the projection method to reduce the loop amplitude containing fermion chain with two massive spinors. The extension is achieved by decomposing one of the massive spinors into two specific massless spinors, "null spinor" and "reference spinor". Then the extended projection method can be safely implemented for all the processes including the production of massive fermions. Finally we present the tensor reduction for the virtual Z boson decaying to top-quark pair to demonstrate our approach.
Calculation of disconnected quark loops in lattice QCD
Zhen Cheng, Jian-bo Zhang, Guang-yi Xiong
Published:   , doi: 10.1088/1674-1137/44/3/033105
Disconnected quark loops are very computer time consuming to calculate in lattice QCD. Stochastic noise methods are generally used to estimate these loops. However, stochastic estimation has large errors in the calculations of these disconnected diagrams. We use symmetric multi-probing source (SMP) method to estimate these disconnected quark loops, the results are compared with \begin{document}$Z(2)$\end{document} noise and spin\begin{document}$-$\end{document}color explicit (SCE) methods on quenched lattice QCD ensemble with lattice volume \begin{document}$12^{3}\times24$\end{document} at lattice spacing \begin{document}$a\approx0.1$\end{document} fm. All results show that the SMP method is very suitable for the calculation of the pseudoscalar disconnected quark loops. However, SMP and SCE methods have no obvious advantage over \begin{document}$Z(2)$\end{document} noise method in the evaluation of the scalar disconnected loops.
Joule-Thomson expansion for the regular(Bardeen)-AdS black hole
Sen Guo, Jin Pu, Qing-Quan Jiang, Xiao-Tao Zu
Published:   , doi: 10.1088/1674-1137/44/3/035102
In this paper, we attempt to study the Joule-Thomson expansion for the regular black hole in an anti-de Sitter background, and obtain the inversion temperature and curve for the Bardeen-AdS black hole in the extended phase space. We investigate the isenthalpic and inversion curves for the Bardeen-AdS black hole in the T-P plane to find the intersection points between them are exactly the inversion points discriminating the heating process from the cooling one. And, the inversion curve for the regular(Bardeen)-AdS black hole is not closed and there is only a lower inversion curve in contrast with that of the Van der Walls fluid. Most importantly, we find the ratio between the minimum inversion and critical temperature for the regular(Bardeen)-AdS black hole is 0.536622, which is always larger than all the already-known ratios for the singular black hole. This larger ratio for the Bardeen-AdS black hole in contrast with the singular black hole may stem from the fact that there is a repulsive de Sitter core near the origin of the regular black hole.
Hunting the Potassium Geoneutrinos with Liquid Scintillator Cherenkov Neutrino Detectors
Zhe Wang, Shaomin Chen
Published:   , doi: 10.1088/1674-1137/44/3/031002
The research of geoneutrino is a new interdisciplinary subject of particle experiments and geo-science. Potassium-40 (40K) decays contribute roughly 1/3 of the radiogenic heat of the Earth, but it is still missing from the experimental observation. Solar neutrino experiments with liquid scintillators have observed uranium and thorium geoneutrinos and are the most promising in the low-background neutrino detection. In this article, we present the new concept of using liquid-scintillator Cherenkov detectors to detect the neutrino-electron elastic scattering process of 40K geoneutrinos. Liquid-scintillator Cherenkov detectors using a slow liquid scintillator can achieve this goal with both energy and direction measurements for charged particles. Given the directionality, we can significantly suppress the dominant intrinsic background originating from solar neutrinos in conventional liquid-scintillator detectors. We simulated the solar- and geo-neutrino scatterings in the slow liquid scintillator detector, and implemented energy and directional reconstructions for the recoiling electrons. We found that 40K geoneutrinos can be detected with three standard deviation accuracy in a kiloton-scale detector.
Phase diagram of two-color QCD matter at finite baryon and axial isospin densities
Jingyi Chao
Published:   , doi: 10.1088/1674-1137/44/3/034108
I study two-color QCD matter with two fundamental quark flavors using both chiral perturbation theory and the Nambu--Jona-Lasinio (NJL) model. The effective Lagrangian is derived in terms of mesons and baryons, i.e., diquarks. These low lying excitations lie in an extended \begin{document}$ {\rm SU}(4)$\end{document} flavor symmetry space. I compute the leading order terms in the Lagrangian as a function of the baryon and axial isospin densities. After numerically solving the gap equations of the two-color NJL model, the phase diagram is plotted in the \begin{document}$\mu-\nu_{5}$\end{document} plane.
Static fluid spheres admitting the Karmarkar condition
Ksh. Newton Singh, Ravindra K. Bisht, S. K. Maurya, N. Pant
Published:   , doi: 10.1088/1674-1137/44/3/035101
In this paper, we have explored a new relativistic anisotropic solution of the Einstein field equations for compact stars under embedding class one condition. For this purpose, we use the embedding class one methodology by employing the Karmarkar condition. By using this methodology, we obtain a particular differential equation that connects both the gravitational potentials \begin{document}$e^{\lambda}$\end{document} and \begin{document}$e^{\nu}$\end{document}. We have solved this particular differential equation choosing a simple form of generalized gravitational potential \begin{document}$g_{rr}$\end{document} to describe a complete structure of the space-time within the stellar configuration. After determining this space-time geometry for the stellar models, we have discussed thermodynamical observables like radial and tangential pressures, matter density, red-shift, the velocity of sound, etc inside the stellar models. We have also performed a complete graphical analysis which shows that our models satisfy all the physical and mathematical requirements of ultra-high dense collapsed structures. Further, we have discussed the moment of inertia and M-R curve for rotating and non-rotating stars.
Statistical method in quark combination model
Yang-Guang Yang, Jun Song, Feng-Lan Shao, Zuo-Tang Liang, Qun Wang
Published:   , doi: 10.1088/1674-1137/44/3/034103
We present a new method of solving the probability distribution for baryons, antibaryons and mesons at the hadronization of constituent quark and antiquark system. The hadronization is governed by the quark combination rule in the quark combination model developed by the Shandong Group. We use the method of the generating function to derive the outcome of the quark combination rule, which is much simpler and easier to be generalized than the original method. Furthermore, we use the formula of the quark combination rule and its generalization to study the property of multiplicity distribution of net-protons. Taking a naive case of quark number fluctuations and correlations at hadronization, we calculate ratios of multiplicity cumulants of final-state net-protons and discuss the potential applicability of quark combination model in studying hadronic multiplicity fluctuations and the underlying phase transition property in relativistic heavy-ion collisions.