oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 4 )

2018 ( 3 )

2017 ( 4 )

2016 ( 13 )

Custom range...

Search Results: 1 - 10 of 3109 matches for " Rahul Sinha "
All listed articles are free for downloading (OA Articles)
Page 1 /3109
Display every page Item
Implications of CKM Unitarity on the search for New Physics in B meson decays
Sinha, Rahul
High Energy Physics - Phenomenology , 2008,
Abstract: This paper has been temporarily withdrawn by the author. A modified version will be resubmitted. One of the trivial solutions was missed with crucial bearing on conclusions.
CP violation in B mesons using Dalitz plot asymmetries
Rahul Sinha
Physics , 1996,
Abstract: We study CP violation in $B\to K^* \ell^+\ell^-$ using generalized Dalitz plot asymmetries in the angular distribution. These new kind of asymmetries are constructed by adding B and ${\bar B}$ events, and do not require flavor or time tagging, nor is the presence of strong phases needed. Using this method one requires about $2 \times 10^8/\eta$ B's to measure the CP violating parameter $\eta$ in the Standard model. The two--Higgs doublet model requires only $10^7$ B's to constrain parameters better than done by the electric dipole moment of the neutron.
CP violating anomalous trilinear gauge couplings from B-> K^*l^+l^-
Nita Sinha,Rahul Sinha
Physics , 1997,
Abstract: 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.
Determination of the angle gamma using B -> D* V modes
Nita Sinha,Rahul Sinha
Physics , 1997, DOI: 10.1103/PhysRevLett.80.3706
Abstract: We propose a method to determine the angle $\gamma=arg(V_{ub})$, using the $B\to D^*V$ ($V=K^*, \rho$) modes. The $D^*$ is considered to decay to $D \pi$. 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 $\gamma$ 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 $\gamma=30^o$) 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 $B^0$.
CP Violation and Lifetime Differences of Neutral B Mesons from Correlated B^0-B^0bar Pairs
Nita Sinha,Rahul Sinha
Physics , 1998, DOI: 10.1103/PhysRevD.59.116001
Abstract: 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 $\Upsilon$ 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.
New Physics Effects and Hadronic Form Factor Uncertainties in B -> K^* l^+ l^-
Diganta Das,Rahul Sinha
Physics , 2012, DOI: 10.1103/PhysRevD.86.056006
Abstract: It is well known that New Physics can contribute to weak decays of heavy mesons via virtual processes during its decays. The discovery of New Physics, using such decays is made difficult due to intractable strong interaction effects needed to describe it. Modes such as B -> K^* l^+ l^- offer an advantage as they provide a multitude of observables via angular analysis. We show how the multitude of "related observables" obtained from B -> K^* l^+ l^-, can provide many new "clean tests" of the Standard Model. The hallmark of these tests is that several of them are independent of the unknown universal form factors in heavy quark effective theory. We derive a relation between observables that is free of form factors and Wilson coefficients, the violation of which will be an unambiguous signal of New Physics. We also derive relations between observables and form factors that are independent of Wilson coefficients and enable verification of hadronic estimates. We show how form factor ratios can be measured directly from helicity fraction with out any assumptions what so ever. We find that the allowed parameter space for observables is very tightly constrained in Standard Model, thereby providing clean signals of New Physics. We examine both the large-recoil and low-recoil regions of the K^* meson and point out special features and derive relations between observables valid in the two limits. In the large-recoil regions several of the relations are unaffected by corrections to all orders in \alpha_s. We present yet another new relation involving only observables that would verify the validity of the relations between form-factors assumed in the low-recoil region. The several relations and constraints derived will provide unambiguous signals of New Physics if it contributes to these decays.
Implications from ${B\to K^*\ell^+\ell^-}$ observables using $3 \text{fb}^{-1}$ of LHCb data
Rusa Mandal,Rahul Sinha
Physics , 2015,
Abstract: The decay mode $B\to K^*\ell^+\ell^-$ results in the measurement of a large number of related observables by studying the angular distribution of the decay products and is regarded as a sensitive probe of physics beyond the standard model. Recently, LHCb has measured several of these observables using $3\text{fb}^{-1}$ data, as a binned function of $q^2$, the dilepton invariant mass squared. We show how data can be used without any approximations to extract theoretical parameters describing the decay and to obtain a relation amongst observables within the standard model. We find three kinds of significant disagreement between theoretical expectations and values obtained by fits. The values of the form factors obtained from experimental data show significant discrepancies when compared with theoretical expectations in several $q^2$ bins. We emphasize that this discrepancy cannot arise due to resonances and non-factorizable contributions from charm loops. Further, a relation between form factors expected to hold at large $q^2$ is very significantly violated. Finally, the relation between observables also indicates some deviations in the forward-backward asymmetry in the same $q^2$ regions. These discrepancies are possible evidence of physics beyond the standard model.
Isolating New Physics Effects from Hadronic Form Factor Uncertainties in B\to K^* \ell^+\ell^-
Diganta Das,Rahul Sinha
Physics , 2012,
Abstract: The discovery of New Physics, using weak decays of mesons is difficult due to intractable strong interaction effects needed to describe it. We show how the multitude of "related observables" obtained from B\to K^* \ell^+\ell^-, can provide many new "clean tests" of the Standard Model. The hallmark of these tests is that several of them are independent of the unknown form factors required to describe the decay using heavy quark effective theory. We derive a relation between observables that is free of form factors and Wilson coefficients, the violation of which will be an unambiguous signal of New Physics. We also derive other relations between observables and form factors that are independent of Wilson coefficients and enable verification of hadronic estimates. We find that the allowed parameter space for observables is very tightly constrained in Standard Model, thereby providing clean signals of New Physics. The relations derived will provide unambiguous signals of New Physics if it contributes to these decays.
Design & Simulation of 128x Interpolator Filter
Rahul Sinha,Sonika Arora
Computer Science , 2012,
Abstract: This paper presents the design consideration and simulation of interpolator of OSR 128. The proposed structure uses the half band filers & Comb/Sinc filter. Experimental result shows that proposed interpolator achieves the design specification, and also has good noise rejection capabilities. The interpolator accepts the input at 44.1 kHz for applications like CD & DVD audio. The interpolation filter can be applied to the delta sigma DAC. The related work is done with the MATLAB & XILINX ISE simulators. The maximum operating frequency is achieved as 34.584 MHz.
Extracting Weak Phase Information from B -> V_1 V_2 Decays
David London,Nita Sinha,Rahul Sinha
Physics , 2000, DOI: 10.1103/PhysRevLett.85.1807
Abstract: 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 $\sin^2 (2\beta + \gamma)$ can be cleanly obtained from the study of decays such as B_d^0(t) -> D^{*\pm} \rho^\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 $\sin^2 \gamma$. There are no penguin contributions to these decays. It is possible that $\sin^2 (2\beta + \gamma)$ will be the second function of CP phases, after $\sin 2\beta$, to be measured at B-factories.
Page 1 /3109
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.