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Emission time sequence of neutron and proton as a probe of α-clustering structure
Bo-Song Huang, Yu-Gang Ma
Neutron-proton momentum correlation functions are constructed from three-body photodisintegration channel, i.e. \begin{document}$core + n + p$\end{document} and used to to explore the spatial-time information of the non-clustering Wood-Saxon spheric structure as well as \begin{document}$\alpha$\end{document}-clustering structures of \begin{document}$^{12}{\rm{C}}$\end{document} or \begin{document}$^{16}{\rm{O}}$\end{document} based on an extended quantum molecular dynamics model. The emission time sequence of neutron and proton is indicated by the ratio of velocity-gated neutron-proton correlation functions, demonstrating its sensitivity to \begin{document}$\alpha$\end{document}-clustering structure. The work sheds light on a new probe for \begin{document}$\alpha$\end{document}-clustering structure.
Systematic Study of odd-mass 151-161Pm and 154,156Pm Isotopes Using Projected Shell Model
Veerta Rani, Preeti Verma, Suram Singh, Manvi Rajput, Arun Bharti, G. H. Bhat, J. A. Sheikh
Enthused by the availability of the recent experimental as well as theoretical data on the energy levels of odd-mass 151-161Pm and odd-odd 154,156Pm, we applied the theoretical framework of the Projected Shell Model with the aim to further understand the nuclear structure of these nuclei. The calculations have reproduced well the experimental data reported on the yrast bands of these isotopes by assuming an axial (prolate) deformation of ~0.3. Other properties along the yrast line, such as transition energies, transition probabilities, etc., have also been discussed. Band diagrams are plotted to understand their intrinsic multi-quasiparticle structure which turn out to be dominated by 1-quasiparticle bands for the odd-mass Pm isotopes and 2-quasiparticle bands for doubly-odd Pm isotopes under study. The present study has not only confirmed the recently reported experimental/ theoretical data but also extended the already available information on the energy levels and added new information on the reduced transition probabilities.
Complete reduction of integrals in two-loop five-light-parton scattering amplitudes
Xin Guan, Xiao Liu, Yan-Qing Ma
We reduce all the most complicated Feynman integrals in two-loop five-light-parton scattering amplitudes to basic master integrals, while other integrals can be reduced even more easily. Our results are expressed as systems of linear relations in block-triangular form, which are very efficient for numerical calculation. Our results are crucial for complete next-to-next-to-leading order QCD calculation for three jets, photons, or hadrons production at hadron colliders. In order to find out the block-triangular relations, we develop a new method which is efficient and general. The method may provide a practical solution for the bottleneck problem of reducing multiloop multiscale integrals.
Measurement of away-side broadening with self-subtraction of flow in Au+Au collisions at $ {\sqrt{{\bf s}_{\bf{NN}}}}$ =200 GeV
J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, E. C. Aschenauer, M. U. Ashraf, F. Atetalla, A. Attri, G. S. Averichev, V. Bairathi, K. Barish, A. J. Bassill, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, J. Bryslawskyj, I. Bunzarov, J. Butterworth, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, F-H. Chang, Z. Chang, N. Chankova-Bunzarova, A. Chatterjee, S. Chattopadhyay, J. H. Chen, X. Chen, J. Cheng, M. Cherney, W. Christie, H. J. Crawford, M. Csanád, S. Das, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, L. Didenko, C. Dilks, X. Dong, J. L. Drachenberg, J. C. Dunlop, T. Edmonds, N. Elsey, J. Engelage, G. Eppley, R. Esha, S. Esumi, O. Evdokimov, J. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, P. Federic, J. Fedorisin, Y. Feng, P. Filip, E. Finch, Y. Fisyak, L. Fulek, C.
High transverse momentum (\begin{document}$ p_T $\end{document}) particle production is suppressed due to parton (jet) energy loss in the hot dense medium created in relativistic heavy-ion collisions. Redistribution of energy at low-to-modest \begin{document}$ p_T $\end{document} has been elusive to measure because of large anisotropic backgrounds. We report a data-driven method for background evaluation and subtraction, exploiting the away-side pseudorapidity gaps, to measure the jetlike correlation shape in Au+Au collisions at \begin{document}$ \sqrt{s_{\rm{NN}}} = 200 $\end{document} GeV with the STAR experiment. The correlation shapes, for trigger particle \begin{document}$ p_T>3\;{\rm{GeV}}/c $\end{document} and various associated particle \begin{document}$ p_T $\end{document} ranges within \begin{document}$ 0.5<p_T<10\;{\rm{GeV}}/c $\end{document}, are consistent with Gaussians and their widths are found to increase with centrality. The results indicate jet broadening in the medium created in central heavy-ion collisions.
Gluon-pair-Creation Production Model of Strong Interaction Vertices
Bing-Dong Wan, Cong-Feng Qiao
By studying the \begin{document}$\eta_c$\end{document} exclusive decay to double glueballs, we introduce a model to mimic phenomenologically the gluon-pair-vacuum interaction vertices, namely the \begin{document}$0^{++}$\end{document} model. Based on this model, we study glueball production in pseudoscalar quarkonium decays, explicitly \begin{document}$\eta_c \to f_0(1500)\eta(1405)$\end{document}, \begin{document}$\eta_b\to f_0(1500)\eta(1405)$\end{document} and \begin{document}$\eta_b\to f_0(1710)\eta(1405)$\end{document} processes. Among them \begin{document}$f_0(1500)$\end{document} and \begin{document}$f_0(1710)$\end{document} are well-known scalars possessing large glue components and \begin{document}$\eta(1405)$\end{document} is a potential candidate for pseudoscalar glueball. The preliminary calculation results indicate that these processes are marginally accessible in the presently running experiments BES III, BELLE II, and LHCb.
Analysis of survival probability based on superasymmetric reaction systems
Na-Na Li, Xiao-Jun Bao
Published:   , doi: 10.1088/1674-1137/44/9/094102
The survival probability of excited compound nucleus was studied by using two different approaches of shell effect washing out with excitation energy based on superasymmetric reaction system. The estimated evaporation residue cross sections based on the two different methods are compared with the available experimental data, and both methods agree with experimental data to some extent for some specific reactions and \begin{document}$ xn$\end{document} emission channels.
Covariant Spin Kinetic Theory I: Collisionless Limit
Yu-Chen Liu, Kazuya Mameda, Xu-Guang Huang
Published:   , doi: 10.1088/1674-1137/44/9/094101
We develop a covariant kinetic theory for massive fermions in curved spacetime and external electromagnetic field based on quantum field theory. We derive four coupled semi-classical kinetic equations accurate at \begin{document}$O(\hbar)$\end{document}, which describe the transports of particle number and spin degrees of freedom. The relation with the chiral kinetic theory is discussed. As an application, we study the spin polarization in the presence of finite Riemann curvature and electromagnetic field in both local and global equilibrium states.
Warm Tachyon Inflation and Swampland Criteria
Abolhassan Mohammadi, Tayeb Golanbari, Haidar Sheikhahmadi, Kosar Sayar, Lila Akhtari, M. A. Rasheed, Khaled Saaidi
Published:   , doi: 10.1088/1674-1137/44/9/095101
The scenario of two components warm tachyon inflation is considered where the tachyon field plays the role of inflaton and drives inflation. During inflation, the tachyon scalar field interacts with the other component of the Universe which is considered as photon gas, i.e. radiation. The interacting term contains a dissipation coefficient, and the study is modeled based on two different and familiar choices of the coefficient that have been studied in the literature. By applying the latest observational data, the acceptable ranges for the free parameters of the model are obtained. For any choice inside the estimated ranges, there is an acceptable concordance between the theoretical predictions and observations. Whereas the model is established based on some assumptions, it is vital to check their validity for the obtained values of the free parameters of the model. It is realized that the model is not self-consistent for all values of the ranges and sometimes the assumptions are violated. Therefore, to have both self-consistency and agreement with data the parameters of the model need to be constrained again. After that, we are going to consider the recently proposed swampland conjecture, which imposes two conditions on the inflationary models. These criteria could rule out some of the inflationary models, however, warm inflation is known as one of those models that could successfully satisfy the swampland criteria. A precise investigation determines that the proposed warm tachyon inflation could not satisfy the swampland criteria for some cases. In fact, for the first case of the dissipation coefficient, where there is dependency only on the scalar field, the model could agree with observational data, however, it is in direct tension with the swampland criteria. But, for the second case where the dissipation coefficient has a dependency on both scalar field and temperature, the model shows an acceptable agreement with observational data and it could properly satisfy the swampland criteria.
Dirac quasinormal modes of Born-Infeld black hole spacetimes
Hong Ma, Jin Li
Published:   , doi: 10.1088/1674-1137/44/9/095102
Quasinormal modes (QNMs) for massless and massive Dirac perturbations of Born-Infeld black holes (BHs) in higher dimensions are investigated. Solving the corresponding master equation in accordance hypergeometric functions and the QNMs are evaluated. We pay more attention to discuss the relationships between QNM frequencies and spacetime dimension. Meanwhile, we discuss the stability of the Born-Infeld BH by calculating the temporal evolution of the perturbation field. Both the perturbation frequencies and the decay rate increase with the enhance of the dimension of spacetime n. This shows that the Born-Infeld BHs become more and more unstable in higher dimensions. Furthermore, the traditional finite difference method is improved, so that it can be used to calculate massive Dirac field. And we elucidate the dynamical evolution of Born-Infeld BHs in massive Dirac field. Because the number of extra dimensions is related to the string scale, there is a relationship between spacetime dimension n and the properties of Born-Infeld BHs which might be advantageous to the development of extra-dimensional brane worlds and string theory.
Abnormal odd-even staggering behavior around 132Sn studied by density functional theory
Haoqiang Shi, Xiao-Bao Wang, Guo-Xiang Dong, Hualei Wang
Published:   , doi: 10.1088/1674-1137/44/9/094108
In this work, we have performed Skyrme density functional theory (DFT) calculations of nuclei around 132Sn to study whether the abnormal odd-even staggering (OES) behavior of binding energies around N = 82 can be reproduced. With the Skyrme force SLy4 and SkM*, we test the volume- and surface-type of pairing forces, and also the intermediate between these two pairing forces, in the Hartree-Fock-Bogoliubov (HFB) approximation with or without the Lipkin-Nogami (LN) approximation or particle number projection after the convergence of HFBLN (PLN). The UNEDF parameter sets are also used. The trend of the neutron OES against the neutron number or proton number does not change much, by tuning the density dependence of the pairing force. And, for the pairing force which is more favoured at the nuclear surface, the larger mass OES is obtained, and vice versa. It seems that the mix between the volume and surface pairing can give better agreement with data. In the studies of the OES, larger ratio of the surface to volume pairing might be favoured. And, in most cases, the OES given by the HFBLN approximation agrees better with the experimental data. We found that both the Skyrme and pairing forces can influence the OES behavior. The mass OES calculated by the UNEDF DFT is explictly smaller than the experimental one. UNEDF1 and UNEDF2 force can reproduce the experimental trend of the abnormal OES around 132Sn. The neutron OES of the tin isotopes given by SkM* force agrees better with the experimental one than that by SLy4 force, in most cases. Both SLy4 and SkM* DFT have difficulties to reproduce the abnormal OES around 132Sn. By the PLN method, the systematics of OES is improved for several combinations of the Skyrme and pairing forces.
Scotogenic dark symmetry as a residual subgroup of Standard Model symmetries
Salvador Centelles Chuliá, Ricardo Cepedello, Eduardo Peinado, Rahul Srivastava
Published:   , doi: 10.1088/1674-1137/44/8/083110
We show that the scotogenic dark symmetry can be obtained as a residual subgroup of the global \begin{document}$U(1)_{B-L}$\end{document} symmetry already present in Standard Model. We propose a general framework where the \begin{document}$U(1)_{B-L}$\end{document} symmetry is spontaneously broken to an even \begin{document}${\cal{Z}}_{2n}$\end{document} subgroup, setting the general conditions for neutrinos to be Majorana and the dark matter stability in terms of the residual \begin{document}${\cal{Z}}_{2n}$\end{document}. Under this general framework, as examples, we build a class of simple models where, in the scotogenic spirit, the dark matter candidate is the lightest particle running inside the neutrino mass loop. The global \begin{document}$U(1)_{B-L}$\end{document} symmetry in our framework being anomaly free can also be gauged in a straightforward manner leading to a richer phenomenology.
Invariant-mass distribution of top-quark pairs and top-quark mass determination
Wan-Li Ju, Guoxing Wang, Xing Wang, Xiaofeng Xu, Yongqi Xu, Li Lin Yang
Published:   , doi: 10.1088/1674-1137/44/9/091001
We investigate the invariant-mass distribution of top-quark pairs near the 2mt threshold, which has strong impact on the determination of the top-quark mass mt. We show that higher-order nonrelativistic corrections lead to large contributions which are not included in the state-of-the-art theoretical predictions. We derive a factorization formula to resum such corrections to all orders in the strong-coupling, and calculate necessary ingredients to perform the resummation at next-to-leading power. We combine the resummation with fixed-order results and present phenomenologically relevant numeric results. We find that the resummation effect significantly enhances the differential cross section in the threshold region, and makes the theoretical prediction more compatible with experimental data. We estimate that using our prediction in the determination of mt will lead to a value closer to the result of direct measurement.
Generalized Uncertainty Principle and Black Hole Thermodynamics
Jin Pu, Qin-Bin Mao, Qing-Quan Jiang, Jing-Xia Yu, Xiao-Tao Zu
Published:   , doi: 10.1088/1674-1137/44/9/095103
Banerjee-Ghosh's work shows that the singularity problem can be naturally avoided by the fact that the black hole evaporation stops at the remnant mass greater than the critical mass when including the GUP effects with the first- and second-order corrections. In this paper, we first follow their steps to reexamine the Banerjee-Ghosh's work, but find an interesting result that the remnant mass is always equal to the critical mass at the final stage of the black hole evaporation with the inclusion of the GUP effects. Then, we use the Hossenfelder's GUP, i.e. another GUP model with higher-order corrections, to restudy the final evolution behavior of the black hole evaporation, and confirm the intrinsic self-consistency between the black hole remnant and critical mass once more. In both cases, we also find that the thermodynamic quantities are not singular at the final stage of the black hole evaporation.
Holographic Technicolor Model and Dark Matter
Yidian CHEN, Xiao-Jun BI, Mei HUANG
Published:   , doi: 10.1088/1674-1137/44/9/093102
We investigate the strongly coupled minimal walking technicolor model (MWT) in the framework of a bottom-up holographic model, where the global \begin{document}$ SU(4)$\end{document} symmetry breaks to \begin{document}$ SO(4)$\end{document} subgroup. In the holographic model, we found that 125 GeV composite Higgs particles and small Peskin-Takeuchi S parameter can be achieved simultaneously. In addition, the model predicts a large number of particles at the TeV scale, including dark matter candidate Technicolor Interacting Massive Particles (TIMPs). If we consider the dark matter nuclear spin-independent cross-section in the range of \begin{document}$ 10^{-45}\sim 10 ^ {-48} \;{\rm{cm}}^2$\end{document}, which can be detected by future experiments, the mass range of TIMPs predicted by the holographic technicolor model is \begin{document}$ 2 \sim 4$\end{document} TeV.
Chiral Magnetic Effect in Isobar Collisions from Stochastic Hydrodynamics
Gui-Rong Liang, Jinfeng Liao, Shu Lin, Li Yan, Miao Li
Published:   , doi: 10.1088/1674-1137/44/9/094103
We study chiral magnetic effect in collisions of AuAu, RuRu and ZrZr at \begin{document}$\sqrt{s_{\rm{NN}}}=200\;{\rm{GeV}}$\end{document}. The axial charge evolution is modeled with stochastic hydrodynamics and geometrical quantities are calculated with Monte Carlo Glauber model. By adjusting the relaxation time of magnetic field, we find our results in good agreement with background subtracted data for AuAu collisions at the same energy. We also make prediction for RuRu and ZrZr collisions. We find a weak centrality dependence of initial chiral imbalance, which implies the centrality dependence of chiral magnetic effect signal comes mainly from those of magnetic field and volume factor. Our results also show an unexpected dependence on system size: while the system of AuAu has larger chiral imbalance and magnetic field, it turns out to have smaller signal for chiral magnetic effect due to the larger volume suppression factor.
The fine micro-thermal structures for the Reissner-Nordström black hole
Zhen-Ming Xu, Bin Wu, Wen-Li Yang
Published:   , doi: 10.1088/1674-1137/44/9/095106
Based on the idea of the black hole molecule proposed in [Phys. Rev. Lett. 115 (2015) 111302], in this paper, by choosing the appropriate extensive variables, we have solved the puzzle whether the molecules of the Reissner-Nordström black hole is an interaction or not through the Ruppeiner thermodynamic geometry. Our results show that the Reissner-Nordström black hole is indeed an interaction system that may be dominated by repulsive interaction. More importantly, with the help of a new quantity, thermal-charge density, we describe the fine micro-thermal structures of the Reissner-Nordström black hole in detail. It presents three different phases, the free, interactive and balanced phases. The thermal-charge density plays a role similar to the order parameter, and the back hole undergoes a new phase transition between the free phase and interactive phase. The competition between the free phase and interactive phase exists, which leads to the extreme behavior of the temperature of the Reissner-Nordström black hole. For extreme Reissner-Nordström black hole, the whole system is completely in the interactive phase. What is more significant is that we provide the thermodynamic micro-mechanism for the formation of the naked singularity of the Reissner-Nordström black hole.
Strong gravitational lensing for photon coupled to Weyl tensor in Kiselev black hole
G. Abbas, Asif Mahmood, M. Zubair
Published:   , doi: 10.1088/1674-1137/44/9/095105
The ambition of the present work is to highlight the phenomena of strong gravitational lensing and deflection angle for the photons coupling with Weyl tensor in a Kiselev black hole. Here, we have extended the prior work of Chen and Jing [1] for Schwarzschild black hole to Kiselev black hole. For this purpose, the equation of motion for the photons coupled to Weyl tensor, null geodesic and equation of photon sphere in a Kiselev black hole spacetime have been formulated. It is found that the equation of motion of the photons depends not only on the coupling between photon and Weyl tensor, but also on the polarization direction of the photons. There is a critical value of the coupling parameter \begin{document}$ \alpha$\end{document} for existence of the marginally circular photon orbit outside the event horizon, which depends on the parameters of black hole and the polarization direction of photons. Further, the polarization directions of coupled photon and the coupling parameter \begin{document}$ \alpha$\end{document}, both modify the features of the photon sphere, the angle of deflection and the functions \begin{document}$ (\bar{a}$\end{document} and \begin{document}$ \bar{b})$\end{document} for the strong gravitational lensing in Kiselev black hole spacetime. In addition to this, the observable gravitational lensing quantities and the shadows of the Kiselev black hole spacetime are presented in detail.
Systematic study of the $\alpha$ decay preformation factor of nuclei around the ${Z=82}$, ${N=126}$ shell closures within a generalized liquid drop model
Hong-Ming Liu, You-Tian Zou, Xiao Pan, Xiao-Jun Bao, Xiao-Hua Li
Published:   , doi: 10.1088/1674-1137/44/9/094106
In this work, we systematically study the \begin{document}$\alpha$\end{document} decay preformation factors \begin{document}$P_{\alpha}$\end{document} and \begin{document}$\alpha$\end{document} decay half-lives of 152 nuclei around Z = 82, N = 126 closed shells based on a generalized liquid drop model while \begin{document}$P_{\alpha}$\end{document} is extracted from the ratio of the calculated \begin{document}$\alpha$\end{document} decay half-life to the experimental one. The results show that there is an obvious linear relationship between \begin{document}$P_{\alpha}$\end{document} and the product of valance protons (holes) \begin{document}$N_p$\end{document} and valance neutrons (holes) \begin{document}$N_n$\end{document}. At the same time, we extract the \begin{document}$\alpha$\end{document} decay preformation factors values of even-even nuclei around Z = 82, N = 126 closed shells from the work of Sun \begin{document}${et\ al.}$\end{document} [J. Phys. G: Nucl. Part. Phys. 45, 075106 (2018)], in which the \begin{document}$\alpha$\end{document} decay preformation factors can be calculated by two different microscopic formulas. We find that the \begin{document}$\alpha$\end{document} decay preformation factors are also related to \begin{document}$N_pN_n$\end{document}. Combining with our previous works [Sun \begin{document}${et\ al.}$\end{document}, Phys. Rev. C 94, 024338 (2016); Deng \begin{document}${et\ al.}$\end{document}, ibid. 96, 024318 (2017); Deng \begin{document}${et\ al.}$\end{document}, ibid. 97, 044322 (2018)] and the work of Seif \begin{document}${et\ al.}$\end{document} [Phys. Rev. C 84, 064608 (2011)], we suspect that this phenomenon of linear relationship for the nuclei around those closed shells is model independent. It may be caused by the effect of the valence protons (holes) and valence neutrons (holes) around the shell closures. Finally, using the formula obtained by fitting the \begin{document}$\alpha$\end{document} decay preformation factor data calculated by the generalized liquid drop model (GLDM), we calculate the \begin{document}$\alpha$\end{document} decay half-lives of these nuclei. The calculated results are agree with the experimental data well.
Rare $\Lambda_b \rightarrow \Lambda l^+ l^- $ decay in the Bethe-Salpeter equation approach
Liang-Liang Liu, Xian-Wei Kang, Zhen-Yang Wang, Xin-Heng Guo
Published:   , doi: 10.1088/1674-1137/44/8/083107
We study the rare decays \begin{document}$\Lambda_b \rightarrow \Lambda l^+ l^-~(l=e,\mu, \tau)$\end{document} in the Bethe-Salpeter equation approach. We find that the branching ratio \begin{document}$Br(\Lambda_b \rightarrow \Lambda \mu^+ \mu^-)\times 10^{6} = 1.051 \sim 1.098$\end{document} in our model. This result agrees with the experimental data well. In the same parameter regions, we find that the branching ratio \begin{document}$Br(\Lambda_b \rightarrow \Lambda e^+ e^-(\tau^+ \tau^-) )\times 10^{6} = 0.252 \sim 0.392 ~(0.286 \sim 0.489)$\end{document}.
A Lattice Study of the Two-photon Decay Widths for Scalar and Pseudo-scalar Charmonium
Ying Chen, Ming Gong, Ning Li, Chuan Liu, Yu-Bin Liu, Zhaofeng Liu, Jian-Ping Ma, Yu Meng, Chao Xiong, Ke-Long Zhang
Published:   , doi: 10.1088/1674-1137/44/8/083108
In this exploratory study, two photon decay widths of pseudo-scalar (\begin{document}$ \eta_c $\end{document}) and scalar (\begin{document}$ \chi_{c0} $\end{document}) charmonium are computed using two ensembles of \begin{document}$ N_f = 2 $\end{document} twisted mass lattice QCD gauge configurations. The simulation is performed two lattice ensembles with lattice spacings \begin{document}$ a = 0.067 $\end{document} fm with size \begin{document}$ 32^3\times{64} $\end{document} and \begin{document}$ a = 0.085 $\end{document} fm with size \begin{document}$ 24^3\times{48} $\end{document}, respectively. The results for the decay widths for the two charmonia are obtained which are in the right ballpark however smaller than the experimental ones. Possible reasons for these discrepancies are discussed.
The running curvaton
Qin Chang, Xiao-Lin Wang, Li-Ting Wang
Published:   , doi: 10.1088/1674-1137/44/8/085103
Inspired by [1], we propose a similar curvaton mechanism whose realization occurs in preheating process, in which the effective mass is running (its potential consists of coupling part and exponential part whose contribution is subdominant comparing to the coupling part). The production of curvaton contains the cases of narrow resonance and broad resonances whose criteria comes via the spectral index of curvaton. Since the inflationary potential is chaotic inflation (quadratic potential), it could smoothly transit into the preheating process. Once the entropy perturbation transferred into curvature perturbation, we will use \begin{document}$ \delta N $\end{document} formalism to investigate its validity. By neglecting the contribution of exponential potential of curvaton, we calculate power spectrum \begin{document}$ P_\zeta $\end{document} and non linear Non-Gaussian parameter \begin{document}$ f_{NL} $\end{document}. Our calculation analytically shows that these two observables are independent of potential of inflaton. Finally, as the curvaton almost decay (inflaton field vanishes), the exponential potential will be approaching a constant of order of cosmological constant, which may play a role of dark energy.
Quark-hadron phase transition in DGP including BD brane
Tayeb Golanbari, Terife Haddad, Abolhassan Mohammadi, M. A. Rasheed, Kh. Saaidi
Published:   , doi: 10.1088/1674-1137/44/8/083109
A DGP brane-world model with a perfect fluid brane matter including a Brans-Dicke (BD) scalar field on brane has been utilized to investigate the problem of the quark-hadron phase (QHP) transition in early times of the Universe evolution. The presence of the BD scalar field comes up with some modification terms in the Friedmann equation. Since the behavior of phase transition strongly depends on the basic evolution equations, even a small change in these relations might come to interesting results about the time of transition. The phase transition is investigated using two scenarios of the first-order phase transition and smooth crossover phase transition. For first-order scenario, which is used for intermediate temperature regime, the evolution of the physical quantities, such as temperature and scale factor, are investigated before, during and after the phase transition. The results show that the transition occurs in about micro-second. In the next part, the phenomenon is studied by assuming a smooth crossover transition where the lattice QCD data is utilized to obtain a realistic equation of state for the matter. The investigation for this part is performed in two regimes of high and low-temperature. Using trace anomaly in the high-temperature regime specifies a simple equation of state which states that the quark-gluon behaves like radiation. However, in the low-temperature regime, the trace anomaly is affected by discretization effects, and the hadron resonance gas model is utilized instead. Using this model, a more realistic equation of state could be found in the low-temperature regime. The crossover phase transition in both regimes is considered. The results determine that the transition occurs at the time around a few micro-second. Also, it is realized that the transition in the low-temperature regime occurs after the transition in the high-temperature regime.
2νββ-decay to first 2+ state with partial isospin symmetry restoration from spherical QRPA calculations
Dong-Liang Fang, Amand Faessler
Published:   , doi: 10.1088/1674-1137/44/8/084104
With partially restored isospin symmetry, we calculate the nuclear matrix element for a special decay mode of 2νββ (two neutrino double beta decay) – the decay to the first 2+ excited states. With the realistic CD-Bonn nuclear force, we analyze the dependence of the nuclear matrix elements on the iso-vector and iso-scalar parts of proton-neutron particle-particle interaction. The dependence on the different nuclear matrix element is observed and the results are explained. We also give the phase space factors with numerical electron wave functions and properly chosen excitation energies. Finally we give our results for the half-lives of this decay mode for different nuclei.
Study of single-particle resonant states with Green’s function method
C. Chen, Z. P. Li, Y.-X. Li, T.-T. Sun
Published:   , doi: 10.1088/1674-1137/44/8/084105
The relativistic mean field theory with the Green's function method is taken to study the single-particle resonant states. Different from our previous work [Phys.Rev.C 90,054321(2014)], the resonant states are identified by searching for the poles of Green's function or the extremes of the density of states. This new approach is very effective for all kinds of resonant states, no matter it is broad or narrow. The dependence on the space size for the resonant energies, widths, and the density distributions in the coordinate space has been checked and it is found very stable. Taking \begin{document}$ ^{120} $\end{document}Sn as an example, four new broad resonant states \begin{document}$ 2g_{7/2} $\end{document}, \begin{document}$ 2g_{9/2} $\end{document}, \begin{document}$ 2h_{11/2} $\end{document} and \begin{document}$ 1j_{13/2} $\end{document} are observed, and also the accuracy for the width of the very narrow resonant state \begin{document}$ 1h_{9/2} $\end{document} is highly improved to be \begin{document}$ 1\times 10^{-8} $\end{document} MeV. Besides, our results are very close to those by the complex momentum representation method and the complex scaling method.
Phenomenological Advantages of the Normal Neutrino Mass Ordering
Shao-Feng Ge, Jing-yu Zhu
Published:   , doi: 10.1088/1674-1137/44/8/083103
The preference of the normal neutrino mass ordering from the recent cosmological constraint and the global fit of neutrino oscillation experiments does not seem like a wise choice at first glance since it obscures the neutrinoless double beta decay and hence the Majorana nature of neutrinos. Contrary to this naive expectation, we point out that the actual situation is the opposite. The normal ordering opens the possibility of excluding the higher solar octant and simultaneously measuring the two Majorana CP phases in future \begin{document}$0 \nu 2 \beta$\end{document} experiments. Especially, the funnel region will completely disappear if the solar mixing angle takes the higher octant. The combined precision measurement by the JUNO and Daya Bay experiments can significantly reduce the uncertainty in excluding the higher octant. With a typical \begin{document}${\cal{O}}({\rm{meV}})$\end{document} sensitivity on the effective mass \begin{document}$|m_{ee}|$\end{document}, the neutrinoless double beta decay experiment can tell if the funnel region really exists and hence exclude the higher solar octant. With the sensitivity further improved to sub-meV, the two Majorana CP phases can be simultaneously determined. The normal neutrino mass ordering clearly shows phenomenological advantages than the inverted one.
Tensor form factors of PP, S, V and A transitions within the standard and the covariant light-front approaches
Qin Chang, Xiao-Lin Wang, Li-Ting Wang
Published:   , doi: 10.1088/1674-1137/44/8/083105
In this paper, we investigate the tensor form factors of \begin{document}$ P\to P,\,S,\,V $\end{document} and A transitions within the standard light-front (SLF) and the covariant light-front (CLF) quark models (QMs). The self-consistency and Lorentz covariance of CLF QM are analyzed via these quantities, and the effects of zero-mode are discussed. For the \begin{document}$ P\to V $\end{document} and A transitions, besides the inconsistence between the results extracted via longitudinal and transverse polarization states, which is caused by the residual \begin{document}$ \omega $\end{document}-dependent spurious contributions, we find and analyze a “new” self-consistence problem of the traditional CLF QM, which is caused by the different strategies for dealing deal with the trace term in CLF matrix element. A possible solution to the problems of traditional CLF QM is discussed and confirmed numerically. Finally, the theoretical predictions for the tensor form factors of some \begin{document}$ c\to q,\,s $\end{document} and \begin{document}$ b\to q,\,s\,,c $\end{document} (\begin{document}$ q = u,d $\end{document}) induced \begin{document}$ P\to P,\,S,\,V $\end{document} and A transitions are updated within the CLF QM with a self-consistent scheme.
Redshift drift in uniformly accelerated reference frame
Zhe Chang, Qing-Hua Zhu
Published:   , doi: 10.1088/1674-1137/44/5/055101
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.