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Register a new userUnparticle physics effects in (Lambda_b -> Lambda + missing energy) processes
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We study unparticle physics effects in (Lambda_b -> Lambda + missing energy) decay with polarized $Lambda_b$ and $Lambda$ baryons. The sensitivity of the branching ratio of this decay and polarizations of (Lambda_b) and (Lambda) baryons on the scale dimension d_U and effective cut-off parameter (Lambda_U) are discussed.
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The mixing of $K^0-bar{K^0}$, $D^0-bar{D^0}$ and $B_{(s)}^0-bar{B^0_{(s)}}$ provides a sensitive probe to explore new physics beyond the Standard Model. The scale invariant unparticle physics recently proposed by Georgi can induce flavor-changing neutral current and contribute to the mixing at tree level. We investigate the unparticle effects on $B^0-bar{B^0}$ and $D^0-bar{D^0}$ mixing. Especially, the newly observed $D^0-bar{D^0}$ mixing sets the most stringent constraints on the coupling of the unparticle to quarks.
We investigate the effects of all flavor blind CP-conserving unparticle operators on 5th force experiments, stellar cooling, supernova explosions and compare the limits with each other and with those obtainable from collider experiments. In general, astrophysical bounds are considerably stronger, however they depend strongly on the dimension d_U of the unparticle operator. While for d_U=1, 5th force experiments yield exceedingly strong bounds, the bounds from stellar and supernova cooling are more comparable for d_U=2, with stellar cooling being most restrictive. Bounds on vectorial unparticle couplings are generally stronger than those on scalar ones.
Recently H. Georgi suggested that a scale invariant unparticle ${mathcal{U}}$ sector with an infrared fixed point at high energy can couple with the SM matter via a higher-dimensional operator suppressed by a high cut-off scale. Intense phenomenological search of this unparticle sector in the collider and flavour physics context has already been made. Here we explore its impact in cosmology, particularly its possible role in the supernovae cooling. We found that the energy-loss rate (and thus the cooling) is strongly dependent on the effective scale LdaU and the anomalous dimension dU of this unparticle theory.
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 put on the initial $Lambda_b$ 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.
We present the prospects of an angular analysis of the $Lambda_b to Lambda(1520)ell^+ell^-$ decay. Using the expected yield in the current dataset collected at the LHCb experiment, as well as the foreseen ones after the LHCb upgrades, sensitivity studies are presented to determine the experimental precision on angular observables related to the lepton distribution and their potential to identify New Physics. The forward-backward lepton asymmetry at low dilepton invariant mass is particularly promising. NP scenarios favoured by the current anomalies in $bto sell^+ell^-$ decays can be distinguished from the SM case with the data collected between the Run 3 and the Upgrade 2 of the LHCb experiment.
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