4,626 research outputs found

### 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 $\bar B\to D^{(*)} \tau \bar \nu$ and $b\to s \mu^+\mu^-$

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 $\gamma$

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

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