相关论文: Testing Time-Reversal: Lambda_b Decays into Polari…

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…

A complete study of the angular distributions of the processes, $\Lambda_b \to {\Lambda} V(1^-)$, with $\Lambda \to p {\pi}^-$ and $V (J/{\Psi}) \to {\ell}^+ {\ell}^-$ or $V ({\rho}^0,\omega) \to {\pi}^+ {\pi}^-,$ is performed. Emphasis is…

In this letter, an overview is given for interesting tests of both CP and Time Reversal symmetries with the beauty baryon $\Lambda_b $. Extensive use of the helicity formalism and HQET is done for all calculations. Then, emphasis is put on…

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…

A study of the decay channels Lambda_{b}-->Lambda V, where V is a vector meson (1^-), has been done by putting together kinematical and dynamical analysis. An intensive use of the helicity formalism is involved on the kinematical side,…

The minimal supersymmetric extension of the standard model allows for some of the coupling strengths to be complex parameters. The presence of such imaginary phases can lead to violations of time reversal invariance, which can be tested if…

We investigate the decay of $\Lambda_b\to\Lambda\nu\bar{\nu}$ with the polarized baryons of $\Lambda_b$ and $\Lambda$. With the most general hadronic form factors, we first study the decay branching ratio and then derive the longitudinal,…

In the framework of the perturbative QCD and the diquark model of baryons we have obtained the fragmentation functions for heavy quark that split into polarized Lambda_b baryons. We predict the longitudinal polarization asymmetry for the…

Having in mind that physical systems have different levels of structure we develop the concept of external, internal and total improper Lorentz transformation (space inversion and time reversal). A particle obtained from the ordinary one by…

A study of the angular distributions of the processes $\Lambda_b \to {\Lambda} V(1^-)$ with $V ({J/\Psi,\rho}^0)$ is performed. Emphasis is put on the initial $\Lambda_b$ polarization and the polarization density-matrices are derived to…

Radiative decays of polarized Lambda_b baryons represent an attractive possibility to measure the helicity of the photon emitted in the b --> s gamma quark transition and thus to subject the Standard Model to a stringent test at existing…

Polarized $\Lambda_b \to \Lambda \gamma$ decays at the Z pole are shown to be well suited for probing a large variety of New Physics effects. A new observable is proposed, the angular asymmetry between the $\Lambda_b$ spin and photon…

An angular analysis of Lambda_b0 -> J/psi Lambda decays is performed using a data sample corresponding to 1.0 fb^{-1} collected in pp collisions at sqrt(s) = 7 TeV with the LHCb detector at the LHC. A parity violating asymmetry parameter…

A measurement of the photon polarization in radiative penguin $B$ decays provides a test of the Standard Model and a probe for New Physics, that can lead to a deviation from the Standard Model prediction of left-handed photons in $b\to s…

We study the decays of $\Lambda_b \to \Lambda_c(\to B_n f) \ell ^- \overline{\nu}$ with $\ell = e, \mu, \tau$, where $B_n$ and $f$ are the daughter baryons and the rest of the particles in $\Lambda_c$ cascade decays, respectively. In…

We calculate the invariant and helicity amplitudes for the nonleptonic decay Lambda_b -> Lambda + J/psi, psi(2S) in the covariant confined quark model. We discuss joint angular decay distributions in the cascade decay Lambda_b -> Lambda(->…

An analysis of the decay $\Lambda_b \to J/\psi(\to\mu^+\mu^-)\Lambda(\to p \pi^-)$ decay is performed to measure the $\Lambda_b$ polarization and three angular parameters in data from pp collisions at $\sqrt{s} =$ 7 and 8 TeV, collected by…

Using the most general, model independent form of effective Hamiltonian, the transverse polarization P_T of Lambda in Lambda_b -> Lambda l^+ l^- decay is studied. It is observed that the averaged <P_T> is very sensitive to the existence of…

The photon polarization in $b \to s \gamma$ transitions is measured for the first time in radiative b-baryon decays exploiting the unique spin structure of $\Lambda_b \to \Lambda \gamma$ decays. A data sample corresponding to an integrated…

The polarization of photons produced in radiative $B^{0}_{s}$ decays is studied for the first time. The data are recorded by the LHCb experiment in $pp$ collisions corresponding to an integrated luminosity of 3fb$^{-1}$ at center-of-mass…