Nonfactorizable B→xcoK Decay and QCD Factorization

We study the unexpectedly large rate for the factorization-forbidden decay B →xcoK within the QCD factorization approach. We use a non-zero gluon mass to regularize the infrared divergences in vertex corrections. The end-point singularities arising from spectator corrections are regularized and carefully estimated by the off-shellness of quarks. We find that the contributions arising from the vertex and leading-twist spectator corrections are numerically small, and the twist-3 spectator contribution with chiral enhancement and linear end-point singularity becomes dominant. With reasonable choices for the parameters, the branching ratio for B → XcoK decay is estimated to be in the range （2 ～ 4）× 10^-4, which is compatible with the Belle and BaBar data.

QCD factorization semi-inclusive deep inelastic scattering diffractive deep inelastic scattering

The operator level proof of factorization theorem exhibited in [ar Xiv：hep-ph/1307.4194] is extended to the semi-inclusive deep inelastic scattering process（SIDIS）. Factorization theorem can be proved at operator level if there are not detected soft hadrons. The key point is that the initial one-nucleon state is the eigenstate of QCD.

Single Transverse Spin Asymmetries at Parton Level

Two factorization approaches have been proposed for single transverse spin asymmetries. One is the cofiinear factorization, the other is the transverse-momentum-dependent factorization. They have been previously derived in a formal way by using diagram expansion at hadron level. If the two factorizations hold or can be proven, they should also hold when we replace hadrons with patton states. We examine these two factorizations at patton level with massless partons. It is nontrivial to generate these asymmetries at parton level with massless patrons because the asymmetries require helicity-flip and nonzero absorptive parts in scattering amplitudes. By constructing suitable patton states with massless partons we derive the two factorizations for the asymmetry in Drell-Yan processes. It is found from our results that the collinear factorization derived at parton level is not the same as that derived at hadron level. Our results with massless partons confirm those derived with single massive parton state in our previous works.

Study on B_d→φK_s Decay in EDQS Model

We study Bd → φKs decay in extra down-type quarks （EDQS） model with a non-universal Z boson associated with flavor changing neutral currents （FCNCs） at the tree level. With the up-to-date experimental data of Br（Bd → φKs）, SCKs, and ACKs, we derive the bounds on the Z-b-s coupling parameter ｜Ubs ｜ and the new weak phase φ, using the constrained parameter spaces, we finally give predictions for Bd → φφ decay, which could be tested at the Fermilab Tevatron and the LHC-b experiments.

Pure annihilation decays of B^(s)_(0)→a^(+)_(0)a^(−)_(0)and B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0)in the PQCD approac

We study the CP-averaged branching fractions and the CP-violating asymmetries in the pure annihilation decays of B^(s)_(0)→a^(+)_(0)a^(−)_(0)and B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0),where a_(0)[K^(∗)_(0)]denotes the scalar a_(0)(980)and a_(0)(1450)[K^(∗)_(0)(800)(orκ)and K^(∗)_(0)(1430)],with the perturbative QCD factorization approach under the assumption of two-quark structure for the a_(0)and K^(∗)_(0)states.The numerical results show that the branching ratios of the B^(0)_(d)→K^(∗+)_(0)K^(∗−)_(0)decays are in the order of 10^(−6),while the decay rates of the B^(s)_(0)→a^(+)_(0)a^(−)_(0)modes are in the order of 10−5.In light of the measured modes with the same quark components in the pseudoscalar sector,namely,B^(0)_(d)→K^(+)k_(-)and B^(0)_(s)→π^(+)π_(−),the predictions for the considered decay modes in this work are expected to be measured at the Large Hadron Collider beauty and/or Belle-Ⅱexperiments in the(near)future.Meanwhile,it is of great interest to find that the twist-3 distribution amplitudesφ^(S)andφ^(T)with inclusion of the Gegenbauer polynomials for the scalar a_(0)(1450)and K^(∗)_(0)(1430)states in scenario 2 contribute slightly to the branching ratios while significantly to the CP violations in the B^(0)_(d)→K^(∗)_(0)(1430)+K^(∗)_(0)(1430)−and B^(0)_(s)→a_(0)(1450)+a_(0)(1450)−decays,which indicates that,compared to the asymptoticφ^(S)andφ^(T),these Gegenbauer polynomials could change the strong phases evidently in these pure annihilation decay channels.These predictions await for the future confirmation experimentally,which could further provide useful information to help explore the inner structure of the scalars and shed light on the annihilation decay mechanism.

Glauber gluon effects in soft collinear factorization

Effects of Glauber gluons,which cause the elastic scattering process between different jets,are studied in the frame of soft-collinear effective theory.Glauber modes are added into the action before being integrated out,which is helpful in studies on the Glauber couplings of collinear and soft particles.It is proved that the final state interactions cancel out for processes inclusive enough.So are interactions with the light cone coordinates x^(+)and x^(-)greater than those of the hard collision.The eikonalization of Glauber couplings of active particles and absorption of these couplings into soft and collinear Wilson lines are discussed,which is related to the loop level definitions of Glauber gluons here.The active-spectator coherence is proved to be harmless to the inclusive summation of spectator-spectator and spectator-soft Glauber exchanges.Based on this result,spectator-spectator and spectator-soft Glauber exchanges cancel out in the processes considered here.Graphic aspects of the cancellation are also discussed to explain relations between the graphic and operator level cancellation of Glauber gluons.

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.

The time-reversal odd side of a jet

We re-examine the jet probes of the nucleon spin and flavor structures.We find for the first time that the time-reversal odd(T-odd)component of a jet,conventionally thought to vanish,can survive due to the non-perturbative fragmentation and hadronization effects.This additional contribution of a jet will lead to novel jet phenomena relevant for unlocking the access to several spin structures of the nucleon,which were thought to be impossible by using jets.As examples,we show how the T-odd constituent can couple to the proton transversity at the Electron Ion Collider(EIC)and can give rise to the anisotropy in the jet production in e^(+)e^(-) annihilations.We expect the T-odd contribution of the jet to have broad applications in high energy nuclear physics.

Resonance contributions fromχ_(c0)in charmless three-body hadronic B meson decays

Within the framework of perturbative QCD factorization,we investigate the nonfactorizable contributions to the factorization-forbidden quasi-two-body decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=π,K.We compare our predicted branching ratios for the B_(()(s))→K_(χc0)→Kπ^(+)π-(K^(+)K^(-))decay with available experiment data as well as predictions by other theoretical studies.The branching ratios of these decays are consistent with data and other theoretical predictions.However,in the Cabibbo-suppressed decays B_((s))→h_((χ)_(c0))→hπ^(+)π^(-)(K^(+)K^(-))with h=K^(0),π,the values of the branching ratios are of the order of 10^(-7)and 10^(-8).The ratio R_((χ)_(c0))between the decays B^(+)→π^(+)χ_(c0)→π^(+)π^(+)π^(-)and B^(+)→K^(+)χc0→K^(+)π^(+)π^(-)and the distribution of branching ratios for different decay modes in invariant mass are considered in this study.

Revisiting radiative leptonic B decay

In this paper,we summarize the existing methods of solving the evolution equation of the leading-twist B-meson LCDA.Then,in the Mellin space,we derive a factorization formula with next-to-leading-logarithmic(NLL)resummation for the form factors FA,V in the B→γℓνdecay at leading power inΛ/mb.Furthermore,we investigate the power suppressed local contributions,factorizable non-local contributions(which are suppressed by 1/Eγand 1/mb),and soft contributions to the form factors.In the numerical analysis,which employs the two-loop-level hard function and the jet function,we find that both the resummation effect and the power corrections can sizably decrease the form factors.Finally,the integrated branching ratios are also calculated for comparison with future experimental data.

Fourth generation effects in ■_s→π^-K+ decay

We study the effects of the fourth quark generation model in Bs→π^-K^＋ decay. Combining with the up-to-date experimental measurement for B（Bs→π^-K^＋） dir - and Acp ^dir（Bs→π^-K^＋） by the CDF Collaboration, we derive the new bound of weak phase Фbd, which are 0° 〈 Фbd 〈 44°,321° 〈 Фbd 〈 360° and 0° 〈 Фbd 〈 26°, 342° 〈Фbd 〈 360° for mr, ： 400 and 600 GeV respectively. In these regions, B（Bs→π^-K^＋） and Acp^dir （Bs→π^-K^＋） consist with the current experimental data within errors.

CP violation in B→φK_S decay in R-parity violating supersymmetry

In the framework of R-parity violating supersymmetry, we investigate the time dependent CP asymmetry SφKs anomaly of B→φKs decay. When the values of the weak phase φ in the R-parity violating coupling fall into certain parameter spaces （246°〈 φ 〈 263°） we find that this anomaly can be easily explained; at the same time, the branching ratio of B→φKs decay can also be in agreement with experimental measurements.

Phenomenological studies on B^(0)→[K^(-)π^(+)]s/v[π^(+)π^(-)]v/s→K^(-)π^(+)π^(+)π^(-)decay

Within the quasi-two-body decay model,we study the localized CP violation and branching fraction of the four-body decay B^(0)→[K^(-)π^(+)]s/v[π^(+)π^(-)]v/s→K^(-)π^(+)π^(+)π^(-)whenthe K^(-)π^(+)andπ^(-)π^(+)pair invariant masses are 0.35<mK^(-)π^(+)<2.04GeV and 0<mπ^(-)π^(+)<1.06 GeV,with the pairs being dominated by the K*0(700)0,K*(892)0,K*(1410)0,K*0(1430)and K*(1680)0,and fo(500),ρ0(770),ω(782)and f0(980)resonances,respectively.When dealing with the dynamical functions of these resonances,f0(500),ρ0(770),f0(980)and K*0(1430)are modeled with the Bugg model,Gounaris-Sakurai function,Flatte formalism and LASS lineshape,respectively,while the others are described by the relativistic Breit-W igner function.Adopting the end point divergence parametersρA∈[0,0.5]andφA∈[0,2π],our predicted results are ACρ(B0→K-π^(+)π^(+)π^(-))∈[-0.365.0.447]and B(B0→K-π^(+)π^(+)π^(-))∈[6.11,185.32]×10^(-8),based on the hypothetical qq structures for the scalar mesons in the QCD factorization ap-proach.Meanwhile,we calculate the CP violating asymmetries and branching fractions of the two-body decaysB0→SV(VS)and all the individual four-body decays B0→SV(VS)→K^(-)π^(+)π^(-)π^(+),respectively.Our theoretical results for the two-body decays B0→K<(892)0 f0(980),B0→K*0(1430)0ω(782),B0→K*(892)0f0(980),B0→K*0(1430)0ρ,and B0→K*0(1430)0ωare consistent with the available experimental data,with the remaining predic-tions await testing in future high precision experiments.

Study of C parity violating and strangeness changing J/ψ→ PP weak decays

Although J/ψ weak decays are rare,they are possible within the standard model of elementary particles.Inspired by the potential prospects of the future intensity frontier,the C parity violating J/ψ→πη^(′),ηη′decays and the strangeness changing J/ψ→πK,Kη^(′)decays are studied via the perturbative QCD approach.It is determined that the J/ψ→ηη^(′) decays have relatively large branching ratios,approximately on the order of 10^(11),which might be within the measurement capability and sensitivity of the future STCF experiment.

Resonancesρ(1450)^(+)andρ(1700)^(+)in B→DKK decays

The contributions for the kaon pair from the intermediate statesρ(1450)^(+) andρ(1700)^(+) in the decays B+→D¯^(0)K+K¯^(0),B^(0)→D−K+K¯^(0),and B^(0)_(s)→D−_(s)K+K¯^(0)are analyzed within the perturbative QCD factorization approach.The decay amplitudes for all concerned decays in this work are dominated by the factorizable Feynman diagrams with the emission of the kaon pair,and the chargedρmesons should be of great importance in the KK channel of the related three-body B decays.Moreover,these quasi-two-body decays are CKM-favored,and the relevant branching ratios are predicted to be in the order of 10^(−5),which have the potential to be measured by experiments.It is also shown that the contributions of the subprocessesρ(1450,1700)^(+)→KK for the three-body B meson decays are considerable according to the total three-body branching fractions presented by Belle.Therefore,the decays B+→D¯^(0)K+K¯^(0),B^(0)→D−K+K¯^(0),and B^(0)_(s)→D−_(s)K^(+)K¯^(0)can be employed to study the properties ofρ(1450)andρ(1700)in the LHCb and Belle-II experiments.

B→Kη^(,) decays in the SM with fourth generation fermions

By employing the perturbative QCD （pQCD） factorization approach, we calculate the new physics contributions to the four B→Kη（＇） decays in the Standard Model （SM） with a fourth generation of fermions （SM4）, induced by the loop diagrams involving t＇ quark. Within the considered parameter space of the SM4 we find that： （a） the next-to-leading order （NLO） pQCD predictions for the branching ratios and CP-violating asymmetries in both the SM and SM4 generally agree with the data within one standard deviation; （b） for Br（B→Kη）, the inclusion of the fourth generation contributions can improve the agreement between the theoretical predictions and the data effectively; （c） however, for Br（B→Kη＇） the decrease due to t＇ loops is disfavored by the data; and, （d） the new physics corrections to the CP-violating asymmetries of the considered decays are only about 10%.