CP\mathbf{\textit{CP}} Violation In The B(s)0\boldsymbol{B^0_{(s)}} System At LHCb

The study of $C\!P$ violation in decays of neutral $B$ mesons provides an important test of the Standard Model (SM) predictions and it is a sensitive probe to search for non-SM physics. In these proceedings I present measurements of $C\!P$ violation in the neutral $B$ meson system. The discussed analyses are based on $pp$-collision data corresponding to an integrated luminosity of 1 $\mathrm{fb}^{-1}$ or 3 $\mathrm{fb}^{-1}$ recorded by the LHCb experiment.Comment: Proceedings of Moriond 2014, EW Interactions and Unified Theories, La Thuile, Aosta valley, Ital

Measurements of B lifetimes at LHCb

Measurements of the $B_s^0$ effective lifetime in decays to CP-odd and CP-even flavour specific final states allow to probe the width difference $\Delta \Gamma_s$ and the CP-violating phase $\phi_s$ of $B^0_s-\bar{B}^0_s$ mixing box-diagram. Measurements of the effective lifetime in the decay channels $B_s^0 \rightarrow K^+ K^-$ and $\bar{B}_s^0 \rightarrow J/\psi f_0(980)$ are presented, as well as a measurement of $\Delta \Gamma_s$ and $\Gamma_s$ performed by a tagged time-dependent angular analysis of $B_s^0 \rightarrow J/\psi \phi$ decays and a measurement of the sign of $\Delta \Gamma_s$, using data collected during 2011 with the LHCb detector.Comment: Proceedings of CKM 2012, the 7th International Workshop on the CKM Unitarity Triangle, University of Cincinnati, USA, 28 September - 2 October 201

b-hadrons lifetime measurements using exclusive b -> J/psi(mu(+) mu(-)) X decays at LHCb

In the proceeding are reported precision measurement of differ ent b-hadrons lifetimes in the exclusive decays B+ -> J / psi K+ , B-0 -> j / psi K-*0 B-s(0) -> J / psi A, using 1 fb(-1) of data collected in 2011 with the LHCb detector at a centre-of-mass energy of 7 TeV

Lifetime measurements in bb-hadron decays at LHCb

Precision lifetime measurements of $b$-flavoured hadrons are an important test of the validity of the theoretical tool used to determine $b$-hadrons observables, the Heavy Quark Expansion. Recent measurements of the $B^+$, $\Lambda^0_b$, $\Xi^-_b$, $\Xi^0_b$ and $\Omega^-_b$ hadrons lifetimes are reported. Moreover, several $B^0$ and $B^0_s$ effective lifetime measurements are discussed, as well as a measurement of the decay width difference in the $B^0$ system, $\Delta \Gamma_d$. All the measurements have been performed using $pp$ collision data collected with the LHCb detector.Comment: Proceedings of the 8th International Workshop on the CKM Unitarity Triangle (CKM 2014), Vienna, Austria, September 8-12, 201

Muon and electron g - 2and proton and cesium weak charges implications on dark Zd models

Theories beyond the standard model involving a sub-GeV-scale vector mediator have been largely studied as a possible explanation of the experimental values of the muon and electron anomalous magnetic moments. Motivated by the recent determination of the anomalous muon magnetic moment performed at Fermilab, we derive the constraints on such a model obtained from the magnetic moment determinations and the measurements of the proton and cesium weak charge, , performed at low-energy transfer. In order to do so, we revisit the determination of the cesium from the atomic parity violation experiment, which depends critically on the value of the average neutron rms radius of , by determining the latter from a practically model-independent extrapolation from the recent average neutron rms radius of performed by the PREX-2 Collaboration. From a combined fit of all the aforementioned experimental results, we obtain rather precise limits on the mass and the kinetic mixing parameter of the boson, namely and , when marginalizing over the mass mixing parameter

Lifetime measurements of beauty hadrons at the LHCb experiment

This thesis presents several lifetime measurements of b-flavoured hadrons at the LHCb experiment. They represent an important test of the theoretical approach to b-hadron observables known as HeavyQuark Expansion (HQE). This analysis uses data corresponding to an integrated luminosity of 1 fb-1 collected in proton-proton collisions at a centre-of-mass energy of 7 TeV. For the decays B+ -> J/psi K+, B0 -> J/psi K*0, B0 -> J/psi K0S, Lambdab -> J/psi Lambda and B0s -> J/psi phi the lifetimes are measured to be tau(B+ -> J/psi K+) = 1.637 +- 0.004 +- 0.003 ps, tau(B0 -> J/psi K*0) = 1.524 +- 0.006 +- 0.004 ps, tau(B0 -> J/psi K0S) = 1.499 +- 0.013 +- 0.005 ps, tau(Lambdab -> J/psi Lambda) = 1.415 +- 0.027 +- 0.006 ps, tau(B0s -> J/psi phi) = 1.480 +- 0.011 +- 0.005 ps, where the first uncertainty is statistical and the second is systematic. These are the most precise lifetime measurements in these decay modes to date. Ratios of these lifetimes also are reported in this thesis, as they are well-defined quantities where many theoretical or experimental uncertainties cancel. The ratio of the decay width difference, Delta Gamma_d, to the average width, Gamma_d, in the B0 system is found to be Delta Gamma_d/ Gamma_d = - 0.044 +- 0.025 +- 0.011. Using data corresponding to an integrated luminosity of 3 fb-1 collected at centre-of-mass energies of 7 TeV and 8 TeV, the measurements of the decay width difference, Delta Gamma_s, and the average width, Gamma_s, in the B0s system are performed. Using the decay B0s -> J/psi phi, they are measured to be Delta Gamma_s = 0.0805 +- 0.0091 +- 0.0033 ps-1, Gamma_s = 0.6603 +- 0.0027 +- 0.0015 ps-1. These are the most precise determinations of these observables ot date. All measurements are consistent with HQE predictions

On the impact of the Migdal effect in reactor CEν\nuNS experiments

The search for coherent elastic neutrino nucleus scattering (CE$\nu$NS) using reactor antineutrinos represents a formidable experimental challenge, recently boosted by the observation of such a process at the Dresden-II reactor site using a germanium detector. This observation relies on an unexpected enhancement at low energies of the measured quenching factor with respect to the theoretical Lindhard model prediction, which implies an extra observable ionization signal produced after the nuclear recoil. A possible explanation for this additional contribution could be provided by the so-called Migdal effect, which however has never been observed. Here, we study in detail the impact of the Migdal contribution to the standard CE$\nu$NS signal calculated with the Lindhard quenching factor, finding that the former is completely negligible for observed energies below $\sim 0.3\,\mathrm{keV}$ where the signal is detectable, and thus unable to provide any contribution to CE$\nu$NS searches in this energy regime. To this purpose, we compare different formalisms used to describe the Migdal effect that intriguingly show a perfect agreement, making our findings robust.Comment: 5 pages, 2 figure

On the impact of the Migdal effect in reactor CEνNS experiments

The search for coherent elastic neutrino nucleus scattering (CEνNS) using reactor antineutrinos represents a formidable experimental challenge, recently boosted by the observation of such a process at the Dresden-II reactor site using a germanium detector. This observation relies on an unexpected enhancement at low energies of the measured quenching factor with respect to the theoretical Lindhard model prediction, which implies an extra observable ionization signal produced after the nuclear recoil. A possible explanation for this additional contribution could be provided by the so-called Migdal effect, which however has never been observed. Here, we study in detail the impact of the Migdal contribution to the standard CEνNS signal calculated with the Lindhard quenching factor, finding that the former is completely negligible for observed energies below ∼0.3keV where the signal is detectable, and thus unable to provide any contribution to CEνNS searches in this energy regime. To this purpose, we compare different formalisms used to describe the Migdal effect that intriguingly show a perfect agreement, making our findings robust