116924725
Can the maximum mass of neutron stars rule out any equation of state of dense stellar matter before gravity is well understood
ABSTRACTProbably No! As an example, using soft EOSs consistent with existing terrestrial nuclear laboratoryexperiments for hybrid neutron stars containing a quark core described with MIT bag model usingreasonable parameters, we show that the recently discovered new holder of neutron star maximummass PSR J1614-2230 of 1.97 ± 0.04M ⊙ can be well described by incorporating a Yukawa gravita-tional correction that is consistent with existing constraints from neutron-proton and neutron-leadscatterings as well as the spectroscopy of antiproton atoms.Subjectheadings: hybrid star, hyperon, quark, gravity 1. INTRODUCTION What is gravity? Are there additional spacetime di-mensions? These are among the Eleven Science Ques-tions for the New Century identiﬁed by the Commit-tee on the Physics of the Universe, US National Re-search Council (CPUNRC 2003). Interestingly, despitethe fact that gravity is the ﬁrst force discovered innature, the quest to unify it with other fundamentalforces remains elusive because of its apparent weaknessat short-distance, see, e.g., refs. (Arkani-Hamed et al.1998; Pea 2001; Hoyle 2003; Long et al. 2003; Jean et al.2003; Boehm et al. 2004a,b; Decca et al. 2005). In de-veloping grand uniﬁcation theories, the conventionalinverse-square-law(ISL) ofNewtonian gravitationalforcehas to be modiﬁed due to either the geometrical ef-fect of the extra spacetime dimensions predicted bystring theories and/or the exchange of weakly interact-ing bosons, such as the neutral spin-1 vector U-boson(Fayet 2009), proposed in the super-symmetric extensionof the Standard Model, see, e.g., refs. (Adelberger et al.2003, 2009; Fischbach 1999; Newman 2009; Uzan 2003;Reynaud 2005) for recent reviews. The modiﬁedgravity has also been proposed as an explanation forthe present period of cosmological acceleration, see,e.g., ref. (DeDeo et al. 2008). The search for evi-dence of modiﬁed gravity is at the forefront of re-search in several sub-ﬁelds of natural sciences includ-ing geophysics, nuclear and particle physics, as wellas astrophysics and cosmology, see, e.g., refs. (Fujii1971; Pea 2001; Hoyle 2003; Arkani-Hamed et al. 1998;Long et al. 2003; Adelberger et al. 2009; Kapner et al.2007; Nesvizhevsky et al. 2008; Kamyshkov et al. 2008;Azam et al. 2008; Geraci et al. 2010; Lucchesi et al.2010). Various upper limits on the deviation from theISL has been put forward down to femtometer range.Since the composition of neutron stars are determinedmainly by the weak and electromagnetic forces throughthe β equilibrium and charge neutrality conditions whiletheir stability is maintained by the balance of strong andgravitationalforces, neutron starsare thus a natural test-ing ground of grand uniﬁcation theories of fundamentalforces. Moreover, neutron stars are among the dens-est objects with the strongest gravity in the Universe,making them ideal places to test strong-ﬁeld predictionsof General Relativity (GR) (Psaltis 2008). The massesand radii of neutron stars are solely determined by boththe strong-ﬁeld behavior of gravity and the Equation ofState (EOS) of dense stellar matter. However, there is nofundamental reason to choose Einstein’s equations overother alternatives and it is known that the GR theoryitself may break down at the limit of very strong gravita-tionalﬁelds, see, e.g., ref. (Psaltis2008) fora comprehen-sive review. In fact, eﬀects of modiﬁed gravity on prop-erties of neutron stars have been under intense investi-gation. As expected, results of these studies are stronglymodel dependent, see, e.g., refs. (Germani et al. 2001;Wiseman 2002; Azam et al. 2008; Krivoruchenko et al.,2009; Wen et al. 2009). Nevertheless, it is very interest-ing to note that alternative gravity theories that haveall passed low-ﬁeld tests but diverge from GR in thestrong-ﬁeld regime predict neutron stars with signiﬁ-cantly diﬀerent properties than their GR counterparts(DeDeo et al. 2003). Moreover, the deviations for neu-tron star properties from the GR predictions for thesetheories are larger than the uncertainty due to the poorlyknown EOS of dense matter in neutron stars. It was alsoclearlyshown that the neutron star maximum mass alonecan not distinguish gravity theories (DeDeo et al. 2003).Furthermore, in the endeavor of testing GR theory ofgravity using properties of neutron stars, it is knownthat there is a degeneracy between the matter contentand gravity. This degeneracy is tied to the fundamentalStrong Equivalence Principle and can only be broken byusing at least two independent observables (Yunes et al.2010).Recently, using the general relativistic Shapiro delaythe mass of PSR J1614-2230 was precisely measured tobe 1.97 ± 0.04M
118388447
Correlations between the nuclear breathing mode energy and properties of asymmetric nuclear matter
Based on microscopic Hartree–Fock + random phase approximation calculations with Skyrme interactions, we study the correlations between the nuclear breathing mode energy EISGMR and properties of asymmetric nuclear matter with a recently developed analysis method. Our results indicate that the EISGMR of 208Pb exhibits moderate correlations with the density slope L of the symmetry energy and the isoscalar nucleon effective mass m*s, 0 besides a strong dependence on the incompressibility K0 of symmetric nuclear matter. Using the present empirical values of L = 60 ± 30 MeV and m*s, 0 = (0.8 ± 0.1)m, we obtain a theoretical uncertainty of about ±16 MeV for the extraction of K0 from the EISGMR of 208Pb. Furthermore, we find that the EISGMR difference between 100Sn and 132Sn strongly correlates with L and thus provides a potentially useful probe of the symmetry energy.
44780624
Partonic Effects on Higher-Order Anisotropic Flows in Relativistic Heavy-Ion Collisions
Higher-order anisotropic flows ${v}_{4}$ and ${v}_{6}$ of charged hadrons in heavy-ion collisions at the Relativistic Heavy Ion Collider are studied in a multiphase transport model that has previously been used successfully for describing the elliptic flow ${v}_{2}$ of identified hadrons in these collisions. We find that the same parton scattering cross section of about $10\phantom{\rule{0.3em}{0ex}}\text{mb}$ used in explaining the measured ${v}_{2}$ of charged hadrons can also reproduce the recent data on their ${v}_{4}$ and ${v}_{6}$ from $\text{Au}+\text{Au}$ collisions at $\sqrt{s}=200A\phantom{\rule{0.3em}{0ex}}\text{GeV}$. It is further found that ${v}_{4}$ is a more sensitive probe of the initial partonic dynamics in these collisions than ${v}_{2}$. Moreover, higher-order parton anisotropic flows are non-negligible and satisfy the scaling relation ${v}_{n,q}({p}_{T})\ensuremath{\sim}{v}_{2,q}^{n∕2}({p}_{T})$, which leads naturally to the observed similar scaling relation among hadron anisotropic flows when the coalescence model is used to describe hadron production from the partonic matter.
119234702
TRITON-3HE RELATIVE AND DIFFERENTIAL FLOWS AND THE HIGH DENSITY BEHAVIOR OF NUCLEAR SYMMETRY ENERGY
Using a transport model coupled with a phase-space coalescence after-burner we study the triton-3He relative and differential transverse flows in semi-central 132Sn + 124Sn reactions at a beam energy of 400 MeV/nucleon. We find that the triton-3He pairs carry interesting information about the density dependence of the nuclear symmetry energy. The t-3He relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.
15108148
Systematic study of the pi(-)/pi(+) ratio in heavy-ion collisions with the same neutron/proton ratio but different masses
National Natural Science Foundation of China 10675148 
10635080 
10575071 
10675082 
MOE of China NCET-05-0392 
Shanghai Rising-Star Program 06QA14024 
SEM of China 
National Basic Research Program of China 2007CB815004 
US National Science Foundation PHY-0652548 
PHY-0757839 
Research Corporation 7123 
Texas Coordinating Board of Higher Education 0035650004- 2007
120983580
Isospin dependent Pauli blocking and nucleon mean free path in isospin-asymmetric nuclear matter
118395281
NLO corrections to $\chi_{bJ}$ to two-$J/\psi$ exclusive decay processes
The next-to-leading order QCD corrections for $\chi_{bJ}$, the p-wave bottomonium, to $J/\psi$ pair decay processes are evaluated utilizing NRQCD factorization formalism. The scale dependence of $\chi_{b2}\rightarrow J/\psi J/\psi$ process is depressed with NLO corrections, and hence the uncertainties in the leading order results are greatly reduced. The total branch ratios are found to be the order of $10^{-5}$ for all three $\chi_{bJ}\rightarrow J/\psi J/\psi$ processes, indicating that they are observable in the LHC and super-B experiments.
137374294
Preliminary Lattice Design of the SSRF Storage Ring
119289860
P-wave quarkonium decays to meson pairs
A bstractThe processes of p-wave Quarkonium exclusive decays to two mesons are investigated, in which the final state vector mesons with various polarizations are considered separately. In the calculation, the initial heavy quarkonia are treated in the framework of non-relativistic quantum chromodynamics, whereas for light mesons, the light cone distribution amplitudes up to twist-3 are employed. It turns out that the higher twist contribution is significant and provides a possible explanation for the observation of the hadron helicity selection rule violated processes χc1→ φφ, ωω by the BESIII collaboration in recently. We also evaluate the χb1→ J/ψJ/ψ process and find that its branching ratio is big enough to be measured at the B-factories.
122248926
Simulation study of beam-beam effects
The Beijing Electron-Positron Collider (BEPC) will be upgraded to BEPCII, and the luminosity will be about 100 times higher. We developed a three-dimensional strong-strong PIC code to study the beam-beam effects in BEPCII. The transportation through the arc is the same as that in Hirata's weak-strong code. The beam-beam force is computed directly by solving the Poisson equation using the Fourier analysis and cyclic reduction method, and the boundary potential is computed by circular convolution. The finite bunch length effect is included by longitudinal slices. An interpolation scheme is used to reduce the required slice number in simulations. The standard message passing interface is used to parallelize the code. The computing time increases linearly with (n+1), where n is the slice number. The calculated luminosity of BEPCII at the design working point is similar to 50% of the design value. The best area in the tune space is near (0.505,0.57) according to the survey, where the luminosity is similar to 80% of the design.
119238467
Orientability of loop processes in relative locality
Inspired by recent results of unusual properties of loop processes in relative locality, we introduce a way to classify loops in the case of kappa-Poincare momentum space. We show that the notion of orientability is deeply connected to a few essential properties of loop processes. Nonorientable loops have "effective curvature", which explicitly breaks translation symmetry, and can lead to a breaking of causality and global momentum conservation. Orientable loops, on the other hand, are "flat." Causality and global momentum conservation are all well preserved in this kind of loops. We comment that the nontrivial classical loops in relative locality might be understood as dual effects from general relativity, and some physical implications are discussed.