Charmed andϕmeson decay constants from 2+1-flavor lattice QCD

On a lattice with 2+1-flavor dynamical domain-wall fermions at the physical pion mass,we calculate the decay constants of D_s^(*) , D^(*) ,and φ .The lattice size is 48^3×96 ,which corresponds to a spatial extension of -5.5 fm,with a lattice spacing of a\approx a≈0.114 fm.For the valence light,strange,and charm quarks,we use overlap fermions at several mass points close to their physical values.Our results at the physical point are f_(D)=213(5) MeV, f_(D)_(s)=249(7) MeV, f_(D)^(*)=234(6) MeV, f_(D)_(s)^(*)=274(7) MeV,and f_(D)_(s)=241(9) MeV.The couplings of D^(*) and D_s^(*) to the tensor current( f_(V)^(T) )can be derived from ratios f_(D)^(*)^T/f_(D)^(*)=0.91(4) and f_(D)_(s)^(*)^T/f_(D)_(s)^(*)=0.92(4) ,respectively,which are the first lattice quantum chromodynamics(QCD)results.We also obtain ratios f_(D)^(*)/f_(D)=1.10(3) and f_(D)_(s)^(*)/f_(D)_(s)=1.10(4) ,which reflect the size of heavy quark symmetry breaking in charmed mesons.Ratios f_(D)_(s)/f_(D)=1.16(3) and f_(D)_(s)^(*)/f_(D)^(*)=1.17(3) can be taken as a measure of SU(3)flavor symmetry breaking.

Holographic Duals of Quark Gluon Plasmas with Unquenched Flavors

We review the construction of gravitational solutions holographically dual to N=1 quiver gauge theories with dynamical flavor multiplets.We focus on the D3-D7 construction and consider the finite temperature,finite quark chemical potential case where there is a charged black hole in the dual solution.Discussed physical outputs of the model include its thermodynamics (with susceptibilities) and general hydrodynamic properties.

Flavor SU(3)topological diagram and irreducible representation amplitudes for heavy meson charmless hadronic decays:mismatch and equivalence

Flavor SU（3） analysis of B meson charmless hadronic two light pseudoscalar decays can be formulated in two different ways. One is to construct the SU（3） irreducible representation amplitude （IRA） according to effective Hamiltonian transformation properties, and the other is to draw the topological diagrams （TDA）. We first point out that previous analyses of TDA and IRA approaches do not match in several aspects, in particular a few SU（3） independent amplitudes have been overlooked in the TDA approach. This has caused confusions in the past and sometimes resulted in incorrect interpretation of data. We then demonstrate that only if these amplitudes are included, a consistent and unified picture can be obtained. With the new TDA amplitudes, all charmless hadronic decays of heavy meson must have nonzero direct CP symmetries as already predicted by the IRA approach. In addition to their notable impact on CP asymmetry, the new amplitudes are also important to extract new physics information.

Lepton mass matrix from double covering of A_(4) modular flavor symmetry

We study a double covering of modular A_(4)flavor symmetry.To this end,we construct lepton models for canonical and radiative seesaw scenarios.Using irreducible doublet representations,heavier Majorana fermion masses are characterized by one free parameter that would differentiate from A_(4)symmetry.symmetry.Throughχsquare numerical analysis,we demonstrate that both scenarios produce some predictions in case of normal hierarchy reproducing neutrino oscillation data.However,no solution satisfies the neutrino oscillation data in case of radiative seesaw of inverted hierarchy.

Chromomagnetic dipole moments of light quarks in the bestest little Higgs model

In this study,we investigated the anomalous Chromomagnetic Dipole Moment(CMDM),denoted as μ_(q)^(BLHM),of light quarks q=(u,c,d,s,b) within the framework of the Bestest Little Higgs Model(BLHM)as an extension of the Standard Model(SM).Our investigation encompassed novel interactions among the light quarks,heavy quark B,and heavy bosons (W'^(±),H^(±),φ^(±),η^(±))incorporating the extended Cabibbo-Kobayashi-Maskawa(CKM)matrix characteristic of the BLHM.We thoroughly explored the permissible parameter space,yielding a spectrum of CMDM values ranging from 10^(-10) to 10^(-3).

Resonant contribution of the three-body decay processB_(s)→K+K−P in perturbative QCD

We investigate CP violation in the decay process B_(s)→ϕ(ρ,ω)P→K^(+)K^(-)P by considering the interference effects ofϕ→K^(+)K^(-),ρ→K^(+)K^(-),andω→K^(+)K^(-)within the framework of the perturbative QCD method(P refers toπ,K,η,andη′pseudoscalar mesons).We analyze the mixings ofϕ−ρ^(0),ϕ−ω,andω−ρ0 and provide the amplitudes of the quasi-two-body decay processes.The CP violation for the B_(s)→K^(+)K^(-)P decay process is obvious in the ranges of the three vector meson interferences.Meanwhile,the localized CP violation can be found to compare with the experimental results from the three-body decay process at the LHC in the near future.

Direct CP violation of three body decay processes from the resonance effect

The physical state of ρ−ω−φ mesons can be mixed using the unitary matrix.The decay processes ω→π^(+)π^(−)and φ→π^(+)π^(−)originate from isospin symmetry breaking.The ρ−ω,ρ−φ,and ω−φ interferences lead to a resonance contribution to produce strong phases.CP violation is considered from isospin symmetry breaking due to the new strong phase of the first order.CP violation can be enhanced greatly for the decay process B^(0)→π^(+)π^(−)η^((′))when the invariant masses of π^(+)π^(−) pairs are in the area around the ω resonance range and φ resonance range in perturbative QCD.We also discuss the possibility of searching for the predicted CP violation at the LHC.

Heavy-light mesons in a relativistic model

We study the heavy-light mesons in a relativistic model, which is derived from the Bethe-Salpeter equation by applying the Foldy-Wouthuysen transformation to the heavy quark. The kernel we choose is based on scalar confinement and vector Coulomb potentials. The transverse interaction of the gluon exchange is also taken into account in this model. The spectra and wave functions of D, Ds, B, Bs meson states are obtained. The spectra are calculated up to the order of 1/mQ, and wave functions are treated to leading order.

The PQCD approach towards to next-to-leading order:A short review

In this short review we elaborate the significance of resummation in kτ factorization theorem,and summarize the recent progresses in the calculations of the next-to-leading order contributions to B meson decays from the perturbative QCD(PQCD)approach.We also comment on the current sta-tus of the PQCD approach and highlight some key issues to develop it in the near future for more phenomenological applications.

Forward-backward asymmetries inΛ_(b)→Λl^(+)l^(-)in the Bethe-Salpeter equation approach

Using the Bethe-Salpeter equation(BSE),we investigate the forward-backward asymmetries(AFB)inΛb→Λl^(+)l^(-)(l=e,μ,τ)in the quark-diquark model.This approach provides precise form factors that are different from those of quantum chromodynamics(QCD)sum rules.We calculate the rare decay form factors forΛb→Λl^(+)l^(-)b and investigate the(integrated)forward-backward asymmetries in these decay channels.We observe the integrated A l FB,ˉA l FB(Λb→Λe^(+)e^(-)=-0.1371,ˉA l FB(Λb→Λμ^(+)μ^(-))=-0.1376,andˉA l FB(Λb→Λτ^(+)τ^(-))=-0.1053;the hadron side asymmetriesˉA h FB(Λb→Λμ^(+)μ^(-))=-0.2315;the lepton-hadron side asymmetriesˉA lh FB(Λb→Λμ^(+)μ^(-))^(-)0.0827;and the longitudinal polarization fractionsˉF L(Λb→Λμ^(+)μ^(-))^(-)0.5681.