3,909 research outputs found
Searching for New Physics by means of Relative Phases and Moduli of Decay Amplitudes
We illustrate some tests which may shed light on physics beyond the Standard
Model. Some of them are especially sensitive to possible signals of new
physics.Comment: 16 page
Decays into -Vector
A complete study of the angular distributions of the processes, , with and or is performed.
Emphasis is put on the initial polarization produced in the
proton-proton collisions. The polarization density-matrices as well as angular
distributions are derived and help to construct T-odd observables which allow
us to perform tests of both Time-Reversal and CP violation.Comment: 10 pages, 2 figure
Angular Analysis of Lambda_b Decays into Lambda v(1-) Applications to Time-Odd Observables and CP violation in Lambda_b Decays (I)
A complete study of teh angualr distributions of the process Lambda_b to
Lambda V(1-) with lambda to p pi- and V(J/Psi) to l+l- or V(rho0,omega, phi) to
pi+ pi-, K+K- is performed. Emphasis is put on the initial Lambda-b
polarization produced in the proton-proton collisions and, without any
dynamical assumption, polarized density-matrices of the vector-mesons V are
derived and help to construct T-odd observables which allow us to perform tests
of both Time-Reversal and CP violation.Comment: 12 pages, 2 figure
Searching for New Physics in the Differential Decay Width of a Lambda_b Semi-leptonic Decay
We propose to investigate the effects of new physics in the semi-leptonic
sequential decay . Firstly, we write the general, model independent, non-covariant
expression of the differential decay width of the process. Then, we calculate
that observable according to three different types of new physics interactions,
which might explain the tension of data with the standard model predictions. We
find that some coefficients of the differential decay width are sensitive to
the kind of interaction that is assumed. The measurements that we suggest seem
to be feasible.Comment: 10 page
Testing Time-Reversal: Lambda_b Decays into Polarized Resonances
Weak decays of beauty baryons like Lambda_b into Lambda V(J^P=1^-), where the
produced resonances are polarized, offer interesting opportunity to perform
tests of Time-Reversal Invariance. This paper emphasizes the particular role of
the resonance polarization-vectors and their physical properties by symmetry
transformations. In particular, it is shown that the normal component of a
polarization-vector, as defined in the Jackson's frame, is Lorentz invariant
and could get large values, notably in the case of J/psi production.Comment: 11 pages, 3 figures, 1 table. Submitted to Phys. Lett.
Model Independent Tests for Time Reversal and CP Violations and for CPT Theorem in \Lambda_b and \bar\Lambda_b Two Body Decays
Weak decays of beauty baryons like \Lambda_b (\bar\Lambda_b) into \Lambda
(\bar\Lambda) and V (J^P = 1^-), where both decay products are polarized, offer
interesting opportunities to perform tests of time reversal and CP violations
and of CPT invariance. We propose a model independent parametrization of the
angular distribution and of the polarization of the final resonances, by means
of the spin density matrix. The transverse component of the polarization is
sensitive to time reversal violations, moreover CP-and CPT-sensitive
observables are defined.Comment: 14 page
Direct CP Violation in B decays with rho0-omega Mixing
A complete study of the process B to pi+ pi- V(V=1--) is performed both in
the framework of the helicity formalism and the effective lagrangian approach.
Emphasis is put on the factorization hypothesis and the importance of the rho0-
omega mixing in enhancing the direct CP violation. New results involving some
branching ratios and the ratio of the Penguin/Tree amplitude are given in
details.Comment: 7 pages, 2 figures. Talk oresented by ZJA at the 18th International
Workshop on High energy Physics and Quantum Field Theory, QFTHEP004,
St-Petersbug, RUSSIA, JUne 17-23, 200
Interference Effects, Time Reversal Violation and Search for New Physics in Hadronic Weak Decays
We propose some methods for studying hadronic sequential two-body decays
involving more spinning particles. It relies on the analysis of T-odd and
T-even asymmetries, which are related to interference terms. The latter
asymmetries turn out to be as useful as the former ones in inferring time
reversal violating observables; these in turn may be sensitive, under some
particular conditions, to possible contributions beyond the standard model. Our
main result is that one can extract such observables even after integrating the
differential decay width over almost all of the available angles. Moreover we
find that the correlations based exclusively on momenta are quite general,
since they provide as much information as those involving one or more spins. We
generalize some methods already proposed in the literature for particular decay
channels, but we also pick out a new kind of time reversal violating
observables. Our analysis could be applied, for example, to data of LHCb
experiment.Comment: 35 page
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