Possible Supersymmetric Effects on Angular Distributions in B→K∗(→Kπ)ℓ+ℓ−B \to K^* (\to K \pi) \ell^+ \ell^- Decays

We investigate the angular distributions of the rare B decay, $B \to K^* (\to K \pi) \ell^+ \ell^-$, in general supersymmetric extensions of the standard model. We consider the new physics contributions from the operators $O_{7,8,9,10}$ in small invariant mass region of lepton pair. We show that the azimuthal angle distribution of the decay can tell us the new physics effects clearly from the behavior of the distribution, even if new physics does not change the decay rate substantially from the standard model prediction

Three heavy jet events at hadron colliders as a sensitive probe of the Higgs sector

Assuming that a non-standard neutral Higgs with an enhanced Yukawa coupling to a bottom quark is observed at future hadron experiments, we propose a method for a better understanding of the Higgs sector. Our procedure is based on "counting" the number of events with heavy jets (where "heavy" stands for a c or b jet) versus b jets, in the final state of processes in which the Higgs is produced in association with a single high p_T c or b jet. We show that an observed signal of the type proposed, at either the Tevatron or the LHC, will rule out the popular two Higgs doublet model of type II as well as its supersymmetric version - the Minimal Supersymmetric Standard Model (MSSM), and may provide new evidence in favor of some more exotic multi Higgs scenarios. As an example, we show that in a version of a two Higgs doublet model which naturally accounts for the large mass of the top quark, our signal can be easily detected at the LHC within that framework. We also find that such a signal may be observable at the upgraded Tevatron RunIII, if the neutral Higgs in this model has a mass around 100 GeV and \tan\beta > 50 and if the efficiency for distinguishing a c jet from a light jet will reach the level of 50%.Comment: Revtex, 11 pages, 4 figures embedded in the text. Main changes with respect to Version 1: Numerical results re-calculated using the CTEQ5L pdf, improved discussion on the experimental consequences, new references added. Conclusions remain unchanged. As will appear in Phys. Rev.

A study of semi-inclusive charmless B→πXB \to \pi X decays

We study semi-inclusive charmless decays $B \to \pi X$ in detail, such as $\bar B^0 \to \pi^{\pm (0)} X$, $B^0 \to \pi^{\pm (0)} X$, $B^{\pm} \to \pi^{\pm (0)} X$, where $X$ does not contain a charm (anti)quark. We find that the process $\bar B^0 \to \pi^- X$ ($B^0 \to \pi^+ X$) can be particularly useful for determination of the CKM matrix element $|V_{ub}|$. We calculate and present the branching ratio (BR) of $\bar B^0 \to \pi^- X$ as a function of $|V_{ub}|$, with an estimate of possible uncertainties. It is expected that the BR is an order of $10^{-4}$. Our estimation indicates that one can phenomenologically determine $|V_{ub}|$ with reasonable accuracy by measuring the BR of $\bar B^0 \to \pi^- X$ ($B^0 \to \pi^+ X$).Comment: 18 pages, 7 figures; Revtex; version accepted for publication in Eur. Phys. J.

Heavy Baryonic Decays of \Lambda_b \to \Lambda \eta^{(\prime)} and Nonspectator Contribution

We calculate the branching ratios of the hadronic \Lambda_b decays to \eta and \eta^\prime in the factorization approximation where the form factors are estimated via QCD sum rules and the pole model. Our results indicate that, contrary to B\to K\eta^{(\prime)} decays, the branching ratios for \Lambda_b\to\Lambda\eta and \Lambda_b\to\Lambda\eta^\prime are more or less the same in the hadronic \Lambda_b transitions. We estimate the branching ratio of \Lambda_b\to\Lambda\eta^{(\prime)} to be 10.80 (10.32)\times 10^{-6} in QCD sum rules, and 2.78 (2.96)\times 10^{-6} in the pole model. We also estimate the nonfactorizable gluon fusion contribution to \Lambda_b\to\Lambda\eta^\prime decay by dividing this process into strong and weak vertices. Our results point to an enhancement of more than an order of magnitude due to this mechanism.Comment: 16 pages, ReVTeX, 5 eps figure

Charm multiplicity and the branching ratios of inclusive charmless b quark decays in the general two-Higgs-doublet models

In the framework of general two-Higgs-doublet models, we calculate the branching ratios of various inclusive charmless b decays by using the low energy effective Hamiltonian including next-to-leading order QCD corrections, and examine the current status and the new physics effects on the determination of the charm multiplicity $n_c$ and semileptonic branching ratio $B_{SL}$. Within the considered parameter space, the enhancement to the ratio $BR(b \to s g)$ due to the charged-Higgs penguins can be as large as a factor of 8 (3) in the model III (II), while the ratio $BR(b \to no charm)$ can be increased from the standard model prediction of 2.49% to 4.91% (2.99%) in the model III (II). Consequently, the value of $B_{SL}$ and $n_c$ can be decreased simultaneously in the model III. The central value of $B_{SL}$ will be lowered slightly by about 0.003, but the ratio $n_c$ can be reduced significantly from the theoretical prediction of $n_c= 1.28 \pm 0.05$ in the SM to $n_c= 1.23 \pm 0.05$, $1.18 \pm 0.05$ for $m_{H^+}=200, 100$ GeV, respectively. We find that the predicted $n_c$ and the measured $n_c$ now agree within roughly one standard deviation after taking into account the effects of gluonic charged Higgs penguins in the model III with a relatively light charged Higgs boson.Comment: 25 pages, Latex file, axodraw.sty, 6 figures. Final version to be published in Phys.Rev.

CP Asymmetries of B→ϕKB \to \phi K and B→η(′)KB \to \eta^{(\prime)} K Decays Using a Global Fit in QCD Factorization

We analyze the CP asymmetries of $B\to \phi K$ and $B\to \eta^{(\prime)} K$ modes in the QCD improved factorization framework. For our calculation we use the phenomenological parameters predetermined from the global fit for the available $B\to PP$ and $VP$ modes (without the quark-level subprocess $b\to s\bar s s$). We show that the large negative $\sin (2\phi_1)_{\phi K_s}$ and the large branching ratio for $B^{\pm}\to \eta' K^{\pm}$ can be simultaneously explained in the context of supersymmetry (SUSY). The R-parity conserving SUGRA models are used and their parameter space is constrained with the observed dark matter relic density along with other experimental constraints. The R-parity violating SUSY models are also used to show that they can provide solutions. We calculate the CP asymmetries for different $B^{\pm (0)} \to \phi K^{\pm (0)}$ and $B^{\pm (0)} \to \eta^{(')} K^{\pm (0)}$ modes and show that the SUSY model predictions are consistent with the available experimental data.Comment: 13 pages, No figure; Some references adde

T-odd Gluon-Top-Quark Effective Couplings at the CERN Large Hadron Collider

The T-odd top-quark chromoelectric dipole moment (tCEDM) is probed through top-quark-pair production via gluon fusion at the CERN Large Hadron Collider (LHC) by considering the possibility of having polarized protons. The complete analytic expressions for the tree-level helicity amplitudes of gg-> ttbar is also presented. For the derived analytic results we determine the 1-sigma statistical sensitivities to the tCEDM form factor for (i) typical CP-odd observables composed of lepton and anti-lepton momenta from t and tbar semileptonic decays for unpolarized protons, and (ii) a CP-odd event asymmetry for polarized protons by using the so-called Berger-Qiu (BQ) parametrization of polarized gluon distribution functions. We find that at the CERN LHC, the CP-odd energy and angular correlations can put a limit of 10^{-18} to 10^{-17} g_scm on the real and imaginary parts of the tCEDM, while the simple CP-odd event asymmetry with polarized protons could put a very strong limit of 10^{-20} g_scm on the imaginary part of the tCEDM.Comment: 14 pages(LaTeX), 1 Postscript figure(use epsfig.sty

The fully differential single-top-quark cross section in next-to-leading order QCD

We present a new next-to-leading order calculation for fully differential single-top-quark final states. The calculation is performed using phase space slicing and dipole subtraction methods. The results of the methods are found to be in agreement. The dipole subtraction method calculation retains the full spin dependence of the final state particles. We show a few numerical results to illustrate the utility and consistency of the resulting computer implementations.Comment: 37 pages, latex, 2 ps figure

FCNC Top Quark Decays in Extra Dimensions

The flavor changing neutral top quark decay t -> c X is computed, where X is a neutral standard model particle, in a extended model with a single extra dimension. The cases for the photon, X= \gamma$, and a Standard Model Higgs boson, X = H, are analyzed in detail in a non-linear$R_\xi gauge. We find that the branching ratios can be enhanced by the dynamics originated in the extra dimension. In the limit where 1/R >> ->, we have found Br(t -> c \gamma) \simeq 10^{-10} for 1/R = 0.5 TeV. For the decay t -> c H, we have found Br(t -> cH) \simeq 10^{-10} for a low Higgs mass value. The branching ratios go to zero when 1/R -> \infty.Comment: Accepted to be published in the Europ. Phys. Jour. C; 16 pages, 2 figure