arXiv subjects

Zhong-Qian Su

Publications and source records attributed to Zhong-Qian Su.

2 recordsLinked to original sources

arXiv2011

Two-pion interferometry for viscous hydrodynamic sources

The space-time evolution of the (1+1)-dimensional viscous hydrodynamics with an initial quark-gluon plasma (QGP) produced in ultrarelativistic heavy ion collisions is studied numerically. The particle-emitting sources undergo a crossover transition from the QGP to hadronic gas. We take into account a usual shear viscosity for the strongly coupled QGP as well as the bulk viscosity which increases significantly in the crossover region. The two-pion Hanbury-Brown-Twiss (HBT) interferometry for the viscous hydrodynamic sources is performed. The HBT analyses indicate that the viscosity effect on the two-pion HBT results is small if only the shear viscosity is taken into consideration in the calculations. The bulk viscosity leads to a larger transverse freeze-out configuration of the pion-emitting sources, and thus increases the transverse HBT radii. The results of the longitudinal HBT radius for the source with Bjorken longitudinal scaling are consistent with the experimental data.

nucl-th↗

arXiv2006

Importance of Higher Twist Effects to Understand Charmed Color-Suppressed $B$ Decays

Working within the framework of the QCD light cone sum rules (LCSR), we compute and discuss the nonfactorizable higher twist effect in $\bar{B}^0\to D^{*0}π^0$ to make an all-around examination of its role in the charmed color-suppressed B decays. Analogously to the case of $\bar{B}^0\to D^{0}π^0$, such effect turns out to be of the same strong phase as the factorizable amplitude, and modifies constructively the magnitude by order $(40-90)%$ so that the effective coefficient $a_2^{f}=C_1+C_2/3$ receives a positive correction comparable numerically with it. Nonleading as the soft effect in question is, our findings for it, along with the previous LCSR analyses of $\bar{B}^0\to D^{0}π^0$, are suggestive of the dominance of soft exchanges in these charmed color suppressed B decays. Also, the emphases are put on importance of understanding intensively various related higher twist and transverse momentum effects to interpret the data on $B \to D^{0(*0)}(π^0,η,η'),J/ψK^{(*)}$.

hep-ph↗