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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.

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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.

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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.

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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.

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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.

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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.

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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.

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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 $(2.6 \pm 0.5)\times 10^{-2}$.

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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

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LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
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<eta<4.5, are determined to be AP(B0) = (-0.35 +/- 0.76 +/- 0.28)% and AP(Bs) = (1.09 +/- 2.61 +/- 0.66)%, where the first uncertainties are statistical and the second systematic

Related links:
LHCC conference poster
© CERN Geneva

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დეტალური ჩანაწერი - მსგავსი ჩანაწერები
დაფოკუსირდი:
Open Days 2013 Posters (58)