Penguins and Mixing Dependent CP Violation

Constraints on angles of Unitarity triangle are reviewed, and in particular constraint on $\gamma$ from limit on $\Delta m_s$ is emphasized. Effects of penguin diagram on measurement of $\beta$ and $\alpha$ are then reviewed. New measurements on $B \to \pi^+\pi^-$ in QCD improved factorization approximation suggest large penguin effects. It is possible to estimate the error in measurement of $\alpha$ as a function of $\gamma$ for different $|V_{ub} /V_{cb}|$ values.Comment: LaTeX, 11 pages, 3 eps figures, Talk presented at the Third International Conference on B Physics and CP Violation, Taipei, December 3-7, 199

Leptoquark explanation of HERA anomaly in the context of gauge unification

We examine the consequences of leptoquark explanation of HERA anomaly in the context of R parity conserving supersymmetric gauge unified theory with the gauge unification scale at $\sim 10^{16}$ GeV. We pointed out the difficulty of constructing a grandunified theory. However gauge unification is still possible at $\sim 10^{16}$ GeV when additional multiplets are introduced. We determine the mass spectrum of these additional fields (fermions and scalars) in gauge mediated and supergravity scenarios. Unique signatures and mass bounds are discussed.Comment: 19 pages(Latex), 1 PS Figur

Consequences of R-Parity violating interactions for anomalies in Bˉ→D(∗)τνˉ\bar B\to D^{(*)} \tau \bar \nu and b→sμ+μ−b\to s \mu^+\mu^-

We investigate the possibility of explaining the enhancement in semileptonic decays of $\bar B \to D^{(*)} \tau \bar \nu$, the anomalies induced by $b\to s\mu^+\mu^-$ in $\bar B\to (K, K^*, \phi)\mu^+\mu^-$ and violation of lepton universality in $R_K = Br(\bar B\to K \mu^+\mu^-)/Br(\bar B\to K e^+e^-)$ within the framework of R-parity violating (RPV) MSSM. Exchange of down type right-handed squark coupled to quarks and leptons yield interactions which are similar to leptoquark induced interactions that have been proposed to explain the $\bar B \to D^{(*)} \tau \bar \nu$ by tree level interactions and $b\to s \mu^+\mu^-$ anomalies by loop induced interactions, simultaneously. However, the Yukawa couplings in such theories have severe constraints from other rare processes in $B$ and $D$ decays. Although this interaction can provide a viable solution to $R(D^{(*)})$ anomaly, we show that with the severe constraint from $\bar B \to K \nu \bar \nu$, it is impossible to solve the anomalies in $b\to s \mu^+\mu^-$ process simultaneously.Comment: RevTex, 13 pages, three figures. In our earlier version, we had neglected a contribution to C^{NP}_9 and obtained erroneous conclusions which we have corrected them in this versio

Triple Neutral Gauge Boson Couplings in Noncommutative Standard Model

It has been shown recently that the triple neutral gauge boson couplings are not uniquely determined in noncommutative extension of the Standard Model (NCSM). Depending on specific schemes used, the couplings are different and may even be zero. To distinguish different realizations of the NCSM, additional information either from theoretical or experimental considerations is needed. In this paper we show that these couplings can be uniquely determined from considerations of unification of electroweak and strong interactions. Using SU(5) as the underlying theory and integrating out the heavy degrees of freedom, we obtain unique non-zero new triple $\gamma\gamma\gamma$, $\gamma \gamma Z$, $\gamma ZZ$, $ZZZ$, $\gamma GG$, $ZGG$ and $GGG$ couplings at the leading order in the NCSM. We also briefly discuss experimental implications.Comment: 8 pages, Latex, no figur

M\"{o}ller and Bhabha scattering in the noncommutative standard model

We study the M\"{o}ller and Bhabha scattering in the noncommutative extension of the standard model(SM) using the Seiberg-Witten maps of this to first order of the noncommutative parameter $\theta_{\mu \nu}$. We look at the angular distribution $d\sigma/d\Omega$ to explore the noncommutativity of space-time at around $\Lambda_{NC} \sim$ TeV and find that the distribution deviates significantly from the one obtained from the commutative version of the standard model.Comment: 15 pages, 14 eps figures.Text is modified a little and version to appear in Phys.Rev.

A method for determining CP violating phase γ\gamma

A new way of determining the phases of weak amplitudes in charged $B$ decays based on SU(3) symmetry is proposed. The CP violating phase $\gamma$ can now be determined without the previous difficulty associated with electroweak penguins.Comment: 9 pages plus one figure, Revte

Weak Phase gamma Using Isospin Analysis and Time Dependent Asymmetry in B_d -> K_s pi^+ pi^-

We present a method for measuring the weak phase gamma using isospin analysis of three body B decays into K pi pi channels. Differential decay widths and time dependent asymmetry in B_d -> K_s pi^+pi^- mode needs to be measured into even isospin pi pi states. The method can be used to extract gamma, as well as, the size of the electroweak penguin contributions. The technique is free from assumptions like SU(3) or neglect of any contributions to the decay amplitudes. By studying different regions of the Dalitz plot, it is possible to reduce the ambiguity in the value of gamma.Comment: 11 pages, 1 figur