Search for the lepton-flavour violating decays B⁰ → K^*0τ^±μ^∓

A first search for the lepton-flavour violating decays B0 →K*0τ±μ∓is presented. The analysis is performed using a sample of proton-proton collision data, collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018, corresponding to an integrated luminosity of 9 fb−1. No significant signal is observed, and upper limits on the branching fractions are determined to be B (B0→K∗0τ+μ−) &lt; 1.0(1.2) × 10−5 and B (B0→K∗0τ−μ+) &lt; 8.2(9.8) × 10−6 at the 90% (95%) confidence level. </p

Λb→Λ(→pπ−)ℓ+ℓ−\Lambda_b\rightarrow \Lambda(\to p \pi^-) \ell^+\ell^- as probe of CP-violating New Physics

We investigate the possible sizes of all the CP-violating asymmetries offered by the angular distribution of rare decay $\Lambda_b\rightarrow \Lambda(\to p \pi^-) \ell^+\ell^-$ in the Standard Model and new physics scenarios motivated by the recent $b\to s \ell^+\ell^-$ anomalies. We work in a model-independent effective theory framework and discuss the sensitivity of CP asymmetries to new ${O}_{9,10}$ operators and their chirality flipped counterparts. We find that the size of many of the CP asymmetries can be at the level of few percent in new physics scenarios consistent with current $b\to s\ell^+\ell^-$ data at level of $1\sigma$. We emphasize that measurements of these CP asymmetries can be used to discriminate different new physics scenarios in $b\to s \ell^+\ell^-$.Comment: 27 pages, 4 captioned figures; v2: fixed typos and added new reference

Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at √⁢=5.02TeV with the LHCb detector

Flow harmonic coefficients, , which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02 TeV. The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features