arXiv subjects

Jian-Qing Shi

Publications and source records attributed to Jian-Qing Shi.

6 recordsLinked to original sources

arXiv2003

Constraints on Supersymmetric Flavor Changing Parameters Using B->PP Decays

We study contributions of quark-squark-gluino interactions in Minimal Supersymmetric Standard Model (MSSM) to B->PP (PP =Kpi, pipi, KK) decays using QCD improved factorization method for the evaluation of the hadronic matrix elements and taking into account renormalization group running of the Wilson coefficients from SUSY scale (~ m_{\tilde q}) to the low energy scale (= m_b) applicable to B decays. Using the most recent experimental data we obtain constraints on flavor changing Supersymmetric (SUSY) parameters (δ_{ij})_{LL, RR}. For ΔS = -1 processes, b-> s gamma is usually considered to give the strongest limits. We, however, find that in some part of the parameter space B-> Kpi processes give stronger bounds. Implications for B^0_s -\bar B^0_s mixing is discussed. We also study cons traints obtained from ΔS = 0 processes B-> pipi, KK, rho gamma and B_d -\bar B_d mixing. In this case, in a large part of the parameter space B_d - \bar B_d provides the best bound, but B-> K^- K^0, rho gamma can still give interesting constraints in a complementary region of the parameter space.

hep-ph↗

arXiv2002

CP violation in $B \to PP$ in the SM with SU(3) symmetry

In this paper we study CP violation in $B\to PP$ decays in the Standard Model using SU(3) flavor symmetry. With SU(3) symmetry only seven hadronic parameters are needed to describe $B\to PP$ decays in the SM when annihilation contributions are neglected. The relevant hadronic parameters can be determined using known experimental data from $B\to ππ$ and $B\to K π$. We predict branching ratios and CP asymmetries for some of the unmeasured $B \to PP$ decays. Some of the CP asymmetries can be large and measured at B factories. The effects of annihilation contributions can also be studied using present experimental data. Inclusion of annihilation contributions introduces six more hadronic parameters. We find that annihilation contributions are in general small, but can have significant effects on CP asymmetries and some $B_s \to PP$.

hep-ph↗

arXiv2001

Constraining R-parity violating couplings from B --> PP decays using QCD improved factorization method

We investigate the role of R-parity violating interaction in the non-leptonic decays of B mesons into two light mesons B --> PP. The decay amplitudes are calculated using the QCD improved factorization method. Using the combined data on B decays from BaBar, Belle and CLEO, we obtain strong constraints on the various products of R-parity violating couplings. Many of these new constraints are stronger than the existing bounds.

hep-ph↗

arXiv2001

Constraints on SUSY Gluonic Dipole Interaction from B\to KπDecays

In low energy SUSY theories exchange of gluino and squark with left-right mixing can produce a large gluonic dipole interaction. In this paper we study the effects of this interaction on $B\to K π$ using QCD improved factorization method. The Standard Model predicts a smaller branching ratio for $B^0 \to \bar K^0 π^0$ than experimental measured one. We find that within the parameter space allowed from $B\to γX_s$ constraint, the SUSY dipole interaction can enhance this branching ratio to agree with the experimental measurement. Combining recent data for all the four $\bar B^0 \to K^- π^+, \bar K^0 π^0$ and $B^- \to K^- π^0, \bar K^0 π^-$ decay modes, we find that the allowed parameter space is reduced significantly compared with that using $B\to X_s γ$ data alone. It is found that even with these constraints, the predictions for CP violation in these modes can be dramatically different from those of the SM predictions.

hep-ph↗

arXiv2000

SU(3) Flavor Symmetry and CP Violating Rate Differences for Charmless $B\to P V$ Decays

We derive several relations between CP violating rate differences $Δ(B\to PV) = Γ(B\to PV) - Γ(\bar B \to \bar P \bar V)$ for charmless $B\to P V$ decays in the Standard Model using SU(3) flavor symmetry. It is found that although the relations between branching ratios of $ΔS = 0$ and $ΔS = -1$ processes are complicated, there are simple relations independent of hadronic models between some of the $ΔS =0$ and $ΔS = -1$ rate differences due to the unitarity property of the Kobayashi-Maskawa matrix, such as $ Δ(B\to π^+ ρ^-) = -Δ(B\to π^+ K^{*-})$, $Δ(B\to π^- ρ^+) = - Δ(K^- ρ^+)$. SU(3) breaking effects are also estimated using factorization approximation. These relations can be tested at B factories in the near future.

hep-ph↗

arXiv1999

Constraints on the phase $γ$ and new physics from $B\to Kπ$ Decays

Recent results from CLEO on $B\to Kπ$ indicate that the phase $γ$ may be substantially different from that obtained from other fit to the KM matrix elements in the Standard Model. We show that $γ$ extracted using $B\to Kπ, ππ$ is sensitive to new physics occurring at loop level. It provides a powerful method to probe new physics in electroweak penguin interactions. Using effects due to anomalous gauge couplings as an example, we show that within the allowed ranges for these couplings information about $γ$ obtained from $B\to K π, ππ$ can be very different from the Standard Model prediction.

hep-ph↗