# Posters

უკანასკნელი დამატებები:
2015-03-06
17:15
Measurement of the semileptonic $CP$ asymmetry in $B^0 - \bar {B^0}$ mixing
 Reference: Poster-2015-478 Keywords:  LHCb Created: 2015. -1 p Creator(s): De Vries, Jacco The semileptonic CP asymmetry in B0−B⎯⎯⎯0 mixing, adsl, is measured in proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb−1, recorded by the LHCb experiment. Semileptonic B0 decays are reconstructed in the inclusive final states D−μ+ and D∗−μ+, where the D− meson decays into the K+π−π− final state, and the D∗− meson into the D⎯⎯⎯0(→K+π−)π− final state. The asymmetry between the numbers of D(∗)−μ+ and D(∗)+μ− decays is measured as a function of the decay time of the B0 mesons. The CP asymmetry is measured to be adsl=(−0.02±0.19±0.30)%, where the first uncertainty is statistical and the second systematic. This is the most precise measurement of adsl to date and is consistent with the prediction from the Standard Model. Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-06
17:03
$\mathcal{CP}$ violating phase $\phi_s$ and penguin pollution in $B_s^0\to J/\psi K^+K^-$ with LHCb
 Reference: Poster-2015-477 Keywords:  LHCb Created: 2015. -1 p Creator(s): Vazquez Sierra, Carlos CP violating phase φs appears in b → anti(c)cs transitions due to the interference between the direct decay and the decay after the Bs⁰-anti(Bs⁰) mixing. In SM, φs = -2βs + δP, where -2βs is related to CKM matrix elements and δP is the penguin phase where contributions due to penguin diagrams are taken into account, being this δP phase also the main source of theoretical uncertainty in φs. This φs phase is very sensitive to possible NP (new particles contributing to box diagrams during the mixing, several possible BSM scenarios are presented), so δP should be estimated in order to disentangle these penguin pollution contributions from possible NP contributions, φs(LHCb) = -2βs + δP + δNP. The decay Bs⁰ → J/ψ K⁺K⁻ is a golden decay for φs measurement: latest LHCb combined result also including Bs⁰ → J/ψ π⁺π⁻ measurements is φs = -0.010 ± 0.039 rad, which is in excellent agreement with SM. The penguin pollution phase δP can be estimated using B⁰ → J/ψ ρ⁰ and Bs⁰ → J/ψ anti(K*⁰) decay channels separately: measurement in B⁰ → J/ψ ρ⁰ decay is |δP| < 0.02 rad at 95% CL. Measurement in Bs⁰ → J/ψ anti(K*⁰) decay channel is still ongoing. Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-06
16:51
Differential branching fraction and angular anaysis of Λb→Λμ+μ− decays
 Reference: Poster-2015-476 Keywords:  LHCb Created: 2015. -1 p Creator(s): Pescatore, Luca The differential branching fraction of the rare decay Λ0b → Λμ+μ− is measured as a function of q2, the square of the dimuon invariant mass. The analysis is performed using data collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb−1. These include evidence for signal at dimuon masses below the square of the J/ψ mass with significance above 3σ. In the q2 intervals where the signal is observed, angular distributions are studied and the forward-backward asymmetries in the dimuon and hadron systems are measured for the first time. Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-06
16:25
Search for Exotics with LHCb
 Reference: Poster-2015-475 Keywords:  LHCb Created: 2015. -1 p Creator(s): Muster, Bastien A search is presented for long-lived particles with a mass between 25 and 50 GeV/c^2 and a lifetime between 1 and 200ps in a sample of proton-proton collisions at a centre-of-mass energy of \sqrt{s} = 7TeV, corresponding to an integrated luminosity of 0.62fb^{-1}, collected by the LHCb detector. The particles are assumed to be pair-produced by the decay of a Standard Model-like Higgs boson. The experimental signature of the long-lived particle is a displaced vertex with two associated jets. No excess above the background is observed and limits are set on the production cross-section as a function of the long-lived particle mass and lifetime. Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-06
16:18
Electroweak Physics in the Forward Region
 Reference: Poster-2015-474 Keywords:  LHCb Created: 2015. -1 p Creator(s): Sirendi, Marek LHCb has an active electroweak physics programme with measurements of inclusive processes such as Z and W production in leptonic final states already published. The EW working group is also branching into jet physics with completed Z+jet and Z+b-jet analyses. Recent results in this field are presented. Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-06
15:25
First Observation and Measurement of the Branching Fraction for the Decay $B^0_S \rightarrow D{_S}^* K$
 Reference: Poster-2015-473 Created: 2015. -1 p Creator(s): Sestini, Lorenzo The Bs -> Ds* K and Bs -> Ds* \pi decays are of paramount interest as they can be used, combined with Bs -> Ds K and Bd -> D* \pi, to measure the weak phase \gamma. We present the first observation of the Bs -> Ds* K decay, where Ds* are reconstructed through the decay chain Ds* -> Ds (-> K K \pi) \gamma, using an integrated luminosity of 3.0 fb^{-1} recorded by the LHCb experiment. Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-05
17:29
LHCb's Real-Time Alignment in Run2
 Reference: Poster-2015-472 Keywords:  LHCb Created: 2015. -1 p Creator(s): Batozskaya, Varvara Stable, precise spatial alignment and PID calibration are necessary to achieve optimal detector performances. During Run2, LHCb will have a new real-time detector alignment and calibration to reach equivalent performances in the online and offline reconstruction. This offers the opportunity to optimise the event selection by applying stronger constraints as well as hadronic particle identification at the trigger level. The required computing time constraints are met thanks to a new dedicated framework using the multi-core farm infrastructure for the trigger. Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-05
17:22
Search for $CP$ violation in $D^0\rightarrow \pi^-\pi^+\pi^0$ decays with the energy test
 Reference: Poster-2015-471 Keywords:  LHCb Created: 2015. -1 p Creator(s): Chen, Shanzhen The LHCb experiment has recorded the world's largest sample of charmed meson decays. This contribution presents a study of a $D^0$ meson decaying into a final state containing a neutral pion in LHCb. The search for $CP$ violation exploits a novel model-independent unbinned technique to assign a $p$-value for the no $CP$ violation hypothesis. With a data sample size exceeding that of previous measurements by almost an order of magnitude the world's best sensitivity is obtained. The $p$-value of no $CP$ violation hypothesis given data of $D^0\rightarrow \pi^-\pi^+\pi^0$ decay analysed is found to be $(2.6 \pm 0.5)\times 10^{-2}$. Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-05
17:14
CKM angle $\gamma$ from LHCb
 Reference: Poster-2015-470 Keywords:  LHCb Created: 2015. -1 p Creator(s): Smith, Jackson Results of the latest $\gamma$ combination from LHCb are presented, along with the six LHCb measurements used as inputs. In addition, the anticipated precision attainable for measuring $\gamma$ after the LHCb Upgrade is outlined Related links:LHCC conference poster © CERN Geneva Access to files

2015-03-05
17:06
Production asymmetries of neutral B mesons in pp collisions at LHCb
 Reference: Poster-2015-469 Keywords:  LHCb Created: 2015. -1 p Creator(s): Ferrari, Fabio The B0bar-B0 and Bsbar-Bs production asymmetries, AP(B0) and AP(Bs), are measured by means of a time-dependent analysis of B0 -> J/\psi K*0, B0 -> D- pi+ and Bs -> Ds- pi+ decays, using a data sample corresponding to an integrated luminosity of 1.0 fb^{-1}, collected by LHCb in pp collisions at a centre-of-mass energy of 7 TeV. The measurements are performed as a function of transverse momentum and pseudorapidity of the B0 and Bs mesons within the LHCb acceptance. The production asymmetries, integrated over pT and eta in the range 4 < pT< 30 GeV/c and 2.5

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