arXiv subjects

Nita Sinha

Publications and source records attributed to Nita Sinha.

42 records · Page 3Linked to original sources

arXiv2001

Squark Mixing Contributions to CP violating phase gamma

We investigate the possibility that the CP violation due to the soft supersymmetry breaking terms in squark mixing can give significant contributions to the various $γ$ related parameters in B decays, different from those of the Standard Model. We derive the new limits on $(δ^u_{12})_{LL,LR,RR}$ and on $(δ^d_{23})_{LL,LR,RR}$ from the recent data on $D^0$--$\bar{D}^0$ oscillation as well as those on $B_s^0$--$\bar{B_s}^0$ oscillation. We show that, together with all the other constraints, the currents limits on these parameters still allow large contributions to the CP violating phases in $B_s^0$--$\bar{B_s}^0$ as well as $D^0$--$\bar{D}^0$ oscillations which will modify some of the proposed measurements of $γ$ parameters in CP violating B decays. However, the current constraints already dictate that the one-loop squark mixing contributions to various B decay amplitudes cannot be competitive with that of the Standard Model (SM), at least for those B decay modes which are dominated the tree level amplitudes within the SM, and therefore they are not significant in contributing to CP asymmetries in the corresponding B decays.

hep-ph↗

arXiv2001

Improving Bounds on Penguin Pollution in B -> pi pi

In the presence of penguin contributions, the indirect CP asymmetry in B0(t) -> pi+ pi- measures sin(2α+ 2θ), where 2θparametrizes the size of the penguin ``pollution.'' We derive a new upper bound on |2θ|, requiring the measurement of of BR(B+ -> pi+ pi0) and an upper bound on B00 \equiv {1\over 2} [BR(B0 -> pi0 pi0) + BR(B0bar -> pi0 pi0)]. The new bound is stronger than those previously discussed in the literature. We also present a lower bound on B00. Current data may suggest that it is not very small, in which case θcan be determined using a complete isospin analysis.

hep-ph↗

arXiv2000

Extracting Weak Phase Information from B -> V_1 V_2 Decays

We describe a new method for extracting weak, CP-violating phase information, with no hadronic uncertainties, from an angular analysis of B -> V_1 V_2 decays, where V_1 and V_2 are vector mesons. The quantity $\sin^2 (2β+ γ)$ can be cleanly obtained from the study of decays such as B_d^0(t) -> D^{*\pm} ρ^\mp, D^{*\pm} a_1^{\mp}, D^{*0} K^{*0}, etc. Similarly, one can use B_s^0(t) -> D_s^{*\pm} K^{*\mp} to extract $\sin^2 γ$. There are no penguin contributions to these decays. It is possible that $\sin^2 (2β+ γ)$ will be the second function of CP phases, after $\sin 2β$, to be measured at B-factories.

hep-ph↗

arXiv1998

CP Violation and Lifetime Differences of Neutral B Mesons from Correlated B^0-B^0bar Pairs

We present a technique to determine the CP violating phases, as well as, the lifetime differences of the mass eigenstates for both $B_d$ and $B_s$, by considering correlated $B\bar{B}$ pairs produced at the $Υ$ resonances. We do not require a detailed time dependent study, but only partial time integrated rates, with the tag time, either preceding or following the decay of the other $B$ meson to a final state f. f may be a CP eigenstate or a non-CP eigenstate.

hep-ph↗

arXiv1997

Determination of the angle gamma using B -> D* V modes

We propose a method to determine the angle $γ=arg(V_{ub})$, using the $B\to D^*V$ ($V=K^*, ρ$) modes. The $D^*$ is considered to decay to $D π$. An interference of the $B \to D^{*0}V$ and $B \to \bar {D^{*0}}V$ amplitudes is achieved by looking at a common final state $f$, in the subsequent decays of $D^0/\bar{D^0}$. A detailed analysis of the angular distribution, allows determination, not only of $γ$ and $|V_{ub}|$, but also all the hadronic amplitudes and strong phases involved. No prior knowledge of doubly Cabibbo suppressed branching ratios of $D$ are required. Large CP violating asymmetries ($\sim30 %$ for $γ=30^o$) are possible if $\bar{D^0} \to f$ is doubly Cabbibo suppressed, while $D^0 \to f$ is Cabbibo allowed, for decays of $B^+$ or $B^0$.

hep-ph↗

arXiv1997

CP violating anomalous trilinear gauge couplings from B-> K^*l^+l^-

We study the contributions of the CP violating anomalous WW-gamma interactions to b->s l^+ l^-. We obtain cutoff independent results on tilde kappa and tilde lambda, by constructing an asymmetry for the process B->K^*l^+l^-, where the B and B bar events are added. We show that a sample of 10^4 B-> K^*e^+e^- events, can yield a bound |tilde kappa| < 0.42 at 90% C.L., which is much tighter than the recent constraint from D0.

hep-ph↗