0000000000084522

AUTHOR

Paolo Gandini

0000-0001-7267-6008

showing 33 related works from this author

Search for theX(4140)state inB+→J/ψϕK+decays

2012

We investigate the decay B+ -> J/psi phi K+ in a search for the X(4140) state, a narrow threshold resonance in the J/psi phi system. The data sample corresponds to an integrated luminosity of 10.4 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV collected by the D0 experiment at the Fermilab Tevatron collider. We observe a mass peak with a statistical significance of 3.1 standard deviations and measure its invariant mass to be M = 4159.0 +/- 4.3(stat) +/- 6.6(syst) MeV and its width to be Gamma = 19.9 +/- 12.6(stat)(-8.0)(+3.0)(syst) MeV.

Particle physicsNuclear and High Energy PhysicsTevatronAnalytical chemistryAstrophysics::Cosmology and Extragalactic Astrophysics7. Clean energy01 natural scienceslaw.inventionNuclear physicslaw0103 physical sciencesInvariant massB mesonFermilabNuclear ExperimentCollider010306 general physicsPhysicsLuminosity (scattering theory)Branching fraction010308 nuclear & particles physicsResonanceState (functional analysis)D0 experimentPhysics::Accelerator PhysicsHigh Energy Physics::ExperimentAtomic physicsProduction ratePhysical Review D
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Study ofB−→DK−π+π−andB−→Dπ−π+π−decays and determination of the CKM angleγ

2015

We report a study of the suppressed B- -> DK-pi(+)pi(-) and favored B- -> D pi(-)pi(+)pi(-) decays, where the neutral D meson is detected through its decays to the K--/+pi(+/-) and CP -even K+K- and pi(+)pi(-) final states. The measurement is carried out using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb(-1). We observe the first significant signals in the CP - even final states of the D meson for both the suppressed B- -> DK-pi(+)pi(-) and favored B- -> D pi(-)pi(+)pi(-) modes, as well as in the doubly Cabibbo suppressed D -> K+pi(-) final state of the B- -> D pi(-)pi(+)pi(-) decay. Evidence for the suppressed d…

PhysicsNuclear and High Energy PhysicsParticle physicsMeson010308 nuclear & particles physicsCabibbo–Kobayashi–Maskawa matrixAnalytical chemistry01 natural sciences0103 physical sciencesD mesonPiCP violation010306 general physicsConjugatePhysical Review D
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Observations of Bs0→ψ(2S)η and B(s)0→ψ(2S)π+π− decays

2013

First observations of the $B^0_s \rightarrow \psi(2S) \eta$, $B^0 \rightarrow \psi(2S) \pi^+ \pi^-$ and $B^0_s \rightarrow \psi(2S) \pi^+ \pi^-$ decays are made using a dataset corresponding to an integrated luminosity of 1.0~$fb^{-1}$ collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV. The ratios of the branching fractions of each of the $\psi(2S)$ modes with respect to the corresponding $J/\psi$ decays are \[ \frac{\mathcal{B}(B^0_s \rightarrow \psi(2S) \eta) }{\mathcal{B}(B^0_s \rightarrow J/\psi \eta)} =0.83\pm0.14\,(stat)\pm0.12\,(syst)\pm0.02\,(\mathcalB}), \] \[ \frac{\mathcal{B}(B^0 \rightarrow \psi(2S) \pi^+ \pi^-)}{\mathcal{…

PhysicsNuclear and High Energy PhysicsParticle physicsMeson010308 nuclear & particles physicsHigh Energy Physics::Phenomenology01 natural sciences0103 physical sciencesPiHigh Energy Physics::ExperimentAstrophysics::Earth and Planetary AstrophysicsNuclear Experiment010306 general physicsAstrophysics::Galaxy AstrophysicsNuclear Physics B
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Amplitude analysis ofB0→D¯0K+π−decays

2015

The Dalitz plot distribution of B-0 -> (D) over bar K-0(+)pi(-) decays is studied using a data sample corresponding to 3.0 fb(-1) of pp collision data recorded by the LHCb experiment during 2011 and 2012. The data are described by an amplitude model that contains contributions from intermediate K* (892)(0), K*(1410)(0), K-2*(1430)(0) and D-2(*)(2460)(-) resonances. The model also contains components to describe broad structures, including the K-0(*)(1430)(0) and D-0(*)(2400)(-) resonances, in the K pi S-wave and the D pi S-and P-waves. The masses and widths of the D-0*(2400)(-) and D-2(*)(2460)(-) resonances are measured, as are the complex amplitudes and fit fractions for all components in…

PhysicsNuclear and High Energy PhysicsParticle physics010308 nuclear & particles physicsCabibbo–Kobayashi–Maskawa matrixScatteringDalitz plot01 natural sciencesFormalism (philosophy of mathematics)Amplitude0103 physical sciencesPiCP violation010306 general physicsPhysical Review D
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Model-Independent Evidence forJ/ψpContributions toΛb0→J/ψpK−Decays

2016

The data sample of Lambda(0)(b) -> J/psi pK(-) decays acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb(-1), is inspected for the presence of J/psi p or J/psi K- contributions with minimal assumptions about K(-)p contributions. It is demonstrated at more than nine standard deviations that Lambda(0)(b) -> J/psi pK(-) decays cannot be described with K- p contributions alone, and that J/psi K- contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for P-c(+)-> J/psi p charmonium-pentaquark states in the same data sample.

PhysicsLuminosity (scattering theory)010308 nuclear & particles physicsQuark modelGeneral Physics and AstronomyLambda01 natural sciencesPentaquarkNuclear physicsBaryon13. Climate action0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsPhysical Review Letters
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First Observation ofD0−D¯0Oscillations inD0→K+π−π+π−Decays and Measurement of the Associated Coherence Parameters

2016

Charm meson oscillations are observed in a time-dependent analysis of the ratio of D0→K+π−π+π− to D0→K−π+π−π+ decay rates, using data corresponding to an integrated luminosity of 3.0fb−1 recorded by the LHCb experiment. The measurements presented are sensitive to the phase-space averaged ratio of doubly Cabibbo-suppressed to Cabibbo-favoured amplitudes rK3πD and the product of the coherence factor RK3πD and a charm mixing parameter y′K3π. The constraints measured are rK3πD=(5.67±0.12)×10−2, which is the most precise determination to date, and RK3πD⋅y′K3π=(0.3±1.8)×10−3, which provides useful input for determinations of the CP-violating phase γ in B±→DK±,D→K∓π±π∓π± decays. The analysis also …

PhysicsCoherence factorMeson010308 nuclear & particles physicsBranching fractionGeneral Physics and Astronomy01 natural sciencesStandard deviationNuclear physicsAmplitudePhase space0103 physical sciencesCP violationCoherence (signal processing)010306 general physicsPhysical Review Letters
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Search for Hidden-Sector Bosons inB0→K*0μ+μ−Decays

2015

A search is presented for hidden-sector bosons, $\chi$, produced in the decay ${B^0\!\to K^*(892)^0\chi}$, with $K^*(892)^0\!\to K^{+}\pi^{-}$ and $\chi\!\to\mu^+\mu^-$. The search is performed using $pp$-collision data corresponding to 3.0 fb$^{-1}$ collected with the LHCb detector. No significant signal is observed in the accessible mass range $214 \leq m({\chi}) \leq 4350$ MeV, and upper limits are placed on the branching fraction product $\mathcal{B}(B^0\!\to K^*(892)^0\chi)\times\mathcal{B}(\chi\!\to\mu^+\mu^-)$ as a function of the mass and lifetime of the $\chi$ boson. These limits are of the order of $10^{-9}$ for $\chi$ lifetimes less than 100 ps over most of the $m(\chi)$ range, a…

PhysicsParticle physics010308 nuclear & particles physicsBranching fractionGeneral Physics and AstronomyOrder (ring theory)01 natural sciencesGradient functionHidden sectorProduct (mathematics)0103 physical sciencesStrong CP problem010306 general physicsAxionBosonPhysical Review Letters
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First observation of the rareB+→D+K+π−decay

2016

The B+→D+K+π- decay is observed in a data sample corresponding to 3.0 fb-1 of pp collision data recorded by the LHCb experiment during 2011 and 2012. The signal significance is 8σ and the branching fraction is measured to be B(B+→D+K+π-)=(5.31±0.90±0.48±0.35)×10-6, where the uncertainties are statistical, systematic and due to the normalization mode B+→D-K+π+, respectively. The Dalitz plot appears to be dominated by broad structures. Angular distributions are exploited to search for quasi-two-body contributions from B+→D2∗(2460)0K+ and B+→D+K∗(892)0 decays. No significant signals are observed and upper limits are set on their branching fractions.

PhysicsAngular distribution010308 nuclear & particles physicsBranching fraction0103 physical sciencesDalitz plotCP violationAtomic physics010306 general physics01 natural sciencesPhysical Review D
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Observation of charmless baryonic decays B(s)0→pp¯h+h′−

2017

Decays of B0 and Bs0 mesons to the charmless baryonic final states pp¯h+h′-, where h and h′ each denote a kaon or a pion, are searched for using the LHCb detector. The analysis is based on a sample of proton-proton collision data collected at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3  fb-1. Four-body charmless baryonic Bs0 decays are observed for the first time. The decays Bs0→pp¯K+K-, Bs0→pp¯K±π∓, B0→pp¯K±π∓ and B0→pp¯π+π- are observed with a significance greater than 5 standard deviations; evidence at 4.1 standard deviations is found for the B0→pp¯K+K- decay and an upper limit is set on the branching fraction for Bs0→pp¯π+π-. Branching fraction…

Nuclear physicsBaryonPhysicsPionMeson010308 nuclear & particles physicsBranching fraction0103 physical sciences010306 general physics01 natural sciencesPhysical Review D
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Search for Structure in theBs0π±Invariant Mass Spectrum

2016

The $B_s^0\pi^\pm$ invariant mass distribution is investigated in order to search for possible exotic meson states. The analysis is based on a data sample recorded with the LHCb detector corresponding to $3$ fb$^{-1}$ of $pp$ collision data at $\sqrt{s} = 7$ and $8$ TeV. No significant excess is found, and upper limits are set on the production rate of the claimed $X(5568)$ state. Upper limits are also set as a function of the mass and width of a possible exotic meson decaying to the $B_s^0\pi^\pm$ final state.

PhysicsParticle physicsLarge Hadron Collider010308 nuclear & particles physicsHigh Energy Physics::PhenomenologySpectrum (functional analysis)General Physics and AstronomyOrder (ring theory)Function (mathematics)State (functional analysis)01 natural sciencesNuclear physicsDistribution (mathematics)0103 physical sciencesHigh Energy Physics::ExperimentInvariant massExotic meson010306 general physicsPhysical Review Letters
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First observation and amplitude analysis of theB−→D+K−π−decay

2015

The B- -> D+K-pi(-) decay is observed in a data sample corresponding to 3.0 fb(-1) of pp collision data recorded by the LHCb experiment during 2011 and 2012. Its branching fraction is measured to be B(B- -> D+K-pi(-)) = (7.31 +/- 0.19 +/- 0.22 +/- 0.39) x 10(-5) where the uncertainties are statistical, systematic and from the branching fraction of the normalization channel B- -> D+pi(-)pi(-), respectively. An amplitude analysis of the resonant structure of the B- -> D+K-pi(-) decay is used to measure the contributions from quasi-two-body B- -> D-0* (2400)K-0(-), B- -> D-2* (2460)K-0(-), and B- -> D-J* (2760)K-0(-) decays, as well as from nonresonant sources. The D-J* (2760)(0) resonance is …

PhysicsNuclear and High Energy PhysicsNuclear magnetic resonanceAmplitude010308 nuclear & particles physicsBranching fraction0103 physical sciencesAnalytical chemistryPiCP violation010306 general physics01 natural sciencesPhysical Review D
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First experimental study of photon polarization in radiative B0s decays.

2017

The polarization of photons produced in radiative $B^{0}_{s}$ decays is studied for the first time. The data are recorded by the LHCb experiment in $pp$ collisions corresponding to an integrated luminosity of 3fb$^{-1}$ at center-of-mass energies of $7$ and $8$TeV. A time-dependent analysis of the $B^{0}_{s} \to \phi \gamma$ decay rate is conducted to determine the parameter ${\mathcal{A}}^\Delta$, which is related to the ratio of right- over left-handed photon polarization amplitudes in $b \to s \gamma$ transitions. A value of ${\mathcal{A}}^\Delta=-0.98^{\,+0.46\,+0.23}_{\,-0.52\,-0.20}$ is measured. This result is consistent with the Standard Model prediction within two standard deviatio…

General PhysicsPhotonModels beyond the standard modeldistributions asymmetries toolPhysics MultidisciplinaryGeneral Physics and AstronomyFOS: Physical sciences01 natural sciencesHigh Energy Physics - ExperimentSettore FIS/04 - Fisica Nucleare e SubnucleareNONuclear physicsPhysics and Astronomy (all)High Energy Physics - Experiment (hep-ex)ASYMMETRIES0103 physical sciencesPhoton polarizationLeptonic semileptonic and radiative decays of bottom mesonDISTRIBUTIONS; ASYMMETRIES; TOOLRadiative transfer[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]DISTRIBUTIONSTOOLSDG 7 - Affordable and Clean Energy010306 general physicsPhysicsScience & Technology02 Physical Sciences/dk/atira/pure/sustainabledevelopmentgoals/affordable_and_clean_energyhep-ex010308 nuclear & particles physicsPhysicsParticle physicsPolarization (waves)HEPB physics photon polarization.3. Good healthLHCbAmplitudePhysical SciencesBottom mesons (|B|>0)High Energy Physics::ExperimentLHCFísica de partículesExperimentsPolarization in interactions and scatteringParticle Physics - Experiment
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Measurement ofCPviolation parameters inB0→DK*0decays

2014

An analysis of B0→DK*0 decays is presented, where D represents an admixture of D0 and D¯0 mesons reconstructed in four separate final states: K−π+, π−K+, K+K− and π+π−. The data sample corresponds to 3.0  fb−1 of proton-proton collision, collected by the LHCb experiment. Measurements of several observables are performed, including CP asymmetries. The most precise determination is presented of rB(DK*0), the magnitude of the ratio of the amplitudes of the decay B0→DK+π− with a b→u or a b→c transition, in a Kπ mass region of ±50  MeV/c2 around the K∗(892) mass and for an absolute value of the cosine of the K*0 helicity angle larger than 0.4.

PhysicsNuclear and High Energy PhysicsParticle physicsMeson010308 nuclear & particles physicsMagnitude (mathematics)ObservableAbsolute value01 natural sciencesHelicityAmplitudeQuantum electrodynamics0103 physical sciencesCP violation010306 general physicsPhysical Review D
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Evidence for Exotic Hadron Contributions toΛb0→J/ψpπ−Decays

2016

A full amplitude analysis of $\Lambda_b^0 \to J/\psi p \pi^-$ decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV $pp$ collisions, corresponding to an integrated luminosity of 3 fb$^{-1}$. A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations $N\to p\pi^-$, either the $P_c(4380)^+$ and $P_c(4450)^+\to J/\psi p$ states, previously observed in $\Lambda_b^0 \to J/\psi p K^-$ decays, or the $Z_c(4200)^-\to J/\psi \pi^-$ state, previously reported in $B^0 \to J/\psi K^+ \pi^-$ decays, or all three, are included in the amplitude models. The data support a model containing all three exotic sta…

PhysicsParticle physics010308 nuclear & particles physicsPartial wave analysisQuark modelGeneral Physics and AstronomyExotic hadronLambda01 natural sciencesLuminosityNuclear physicsAmplitude0103 physical sciencesHigh Energy Physics::ExperimentProduction (computer science)010306 general physicsNucleonPhysical Review Letters
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Observation ofJ/ψpResonances Consistent with Pentaquark States inΛb0→J/ψK−pDecays

2015

Observations of exotic structures in the J/ψp channel, that we refer to as pentaquark-charmonium states, in Λ0b→J/ψK−p decays are presented. The data sample corresponds to an integrated luminosity of 3/fb acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis is performed on the three-body final-state that reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the J/ψp mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of 4380±8±29 MeV and a width of 205±1…

PhysicsParticle physicsMeson010308 nuclear & particles physicsHadronGeneral Physics and AstronomyParity (physics)Exotic hadron01 natural sciencesPentaquarkBaryonNuclear physicsAmplitude0103 physical sciencesMass spectrumHigh Energy Physics::Experiment10. No inequality010306 general physicsPhysical Review Letters
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Studies of the resonance structure inD0→KS0K±π∓decays

2016

Amplitude models are constructed to describe the resonance structure of D0→ K-π+π+π- and D0→ K+π-π-π+ decays using pp collision data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb experiment, corresponding to an integrated luminosity of 3.0 fb- 1. The largest contributions to both decay amplitudes are found to come from axial resonances, with decay modes D0→ a1(1260) +K- and D0→ K1(1270 / 1400) +π- being prominent in D0→ K-π+π+π- and D0→ K+π-π-π+, respectively. Precise measurements of the lineshape parameters and couplings of the a1(1260) +, K1(1270) - and K(1460) - resonances are made, and a quasi model-independent study of the K(1460) - resonance is performed. The coher…

PhysicsLarge Hadron Collider010308 nuclear & particles physicsResonance01 natural sciencesLuminosityNuclear physicsAmplitudePhase space0103 physical sciencesCoherence (signal processing)CP violationCharm (quantum number)Atomic physics010306 general physicsPhysical Review D
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Evidence for the Strangeness-Changing Weak DecayΞb−→Λb0π−

2015

Using a pp collision data sample corresponding to an integrated luminosity of 3.0  fb^{-1}, collected by the LHCb detector, we present the first search for the strangeness-changing weak decay Ξ_{b}^{-}→Λ_{b}^{0}π^{-}. No b hadron decay of this type has been seen before. A signal for this decay, corresponding to a significance of 3.2 standard deviations, is reported. The relative rate is measured to be f_{Ξ_{b}^{-}}/f_{Λ_{b}^{0}}B(Ξ_{b}^{-}→Λ_{b}^{0}π^{-})=(5.7±1.8_{-0.9}^{+0.8})×10^{-4},where f_{Ξ_{b}^{-}} and f_{Λ_{b}^{0}} are the b→Ξ_{b}^{-} and b→Λ_{b}^{0} fragmentation fractions, and B(Ξ_{b}^{-}→Λ_{b}^{0}π^{-}) is the branching fraction. Assuming f_{Ξ_{b}^{-}}/f_{Λ_{b}^{0}} is bounded b…

PhysicsCrystallographyBranching fractionHadronPiGeneral Physics and AstronomyAstrophysicsStrangenessLambdaPhysical Review Letters
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Measurement of the Ratio of Branching FractionsB(B¯0→D*+τ−ν¯τ)/B(B¯0→D*+μ−ν¯μ)

2015

The branching fraction ratio R(D-*) = B((B) over bar (0) -> D-*(+)tau(-)(nu) over bar (tau))/B((B) over bar (0) -> D-*(+)mu(-)(nu) over bar (mu)) is measured using a sample of proton-proton collision data corresponding to 3.0 fb(-1) of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode tau(-) -> mu(-)(nu) over bar (mu)nu(tau). The semitauonic decay is sensitive to contributions from non-standard-model particles that preferentially couple to the third generation of fermions, in particular, Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate (B) over bar (0) decays gives R(D-*) =…

PhysicsParticle physicsLarge Hadron Collider010308 nuclear & particles physicsBranching fractionHigh Energy Physics::PhenomenologyGeneral Physics and AstronomyFermion7. Clean energy01 natural sciencesThird generationNuclear physics0103 physical sciencesHigh Energy Physics::ExperimentLeptoquark010306 general physicsLeptonPhysical Review Letters
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Search for weakly decaying b -flavored pentaquarks

2018

Investigations of the existence of pentaquark states containing a single $b$ (anti)quark decaying weakly into four specific final states J/$\psi K^+\pi^- p$, J/$\psi K^- \pi^- p$, J/$\psi K^- \pi^+ p$, and $J/\psi \phi (1020) p$ are reported. The data sample corresponds to an integrated luminosity of 3.0/fb in 7 and 8 TeV pp collisions acquired with the LHCb detector. Signals are not observed and upper limits are set on the product of the production cross section times branching fraction with respect to that of the $\Lambda_b$.

baryon: exoticPhysics and Astronomy (miscellaneous)7000 GeV-cms8000 GeV-cms01 natural sciencesPhysics Particles & FieldsSettore FIS/04 - Fisica Nucleare e SubnucleareHigh Energy Physics - ExperimentLuminosityHigh Energy Physics - Experiment (hep-ex)Hadron-Hadron scattering (experiments)scattering [p p][PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]exotic [baryon]LHCb - Abteilung HintonpentaquarkPhysics8000 GeV-cmsPhysicsParticle physicsPentaquark3. Good healthchannel cross section: branching ratio: upper limitExotic baryonpentaquark --> J/psi(3100) K- pi+ pBranching fraction Hadron-Hadron scattering (experiments) QCDpentaquark --> J/psi(3100) K- pi- pCERN LHC Coll7000 GeV-cmsPhysical Sciencespentaquark --> J/psi(3100) Phi(1020) pBranching fractionLHCcolliding beams [p p]Particle Physics - ExperimentQuarkParticle physicsp p: scatteringFOS: Physical sciencesAstronomy & AstrophysicsHadronsNOmultiquark[ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex]0103 physical sciencesddc:530010306 general physicsLarge Hadron Collider (France and Switzerland)Science & Technologybranching ratio: upper limit [channel cross section]hep-ex010308 nuclear & particles physicsBranching fractionpentaquark --> J/psi(3100) K+ pi- pParticles and FieldGran Col·lisionador d'HadronsBottom quarkQCDLHC-BHEPLHCbHigh Energy Physics::ExperimentFísica de partículesExperimentsp p: colliding beamsexperimental resultsPhysical Review D
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Measurement of CP asymmetries in two-body B(s)0 -meson decays to charged pions and kaons

2018

The time-dependent CP asymmetries in B0→π+π− and B0s→K+K− decays are measured using a data sample of p p collisions corresponding to an integrated luminosity of 3.0  fb−1, collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV. The same data sample is used to measure the time-integrated CP asymmetries in B0→K+π− and B0s→π+K− decays. The results are Cπ+π−=−0.34±0.06±0.01, Sπ+π−=−0.63±0.05±0.01, CK+K−=0.20±0.06±0.02, SK+K−=0.18±0.06±0.02, AΔΓK+K−=−0.79±0.07±0.10, AB0CP=−0.084±0.004±0.003, and AB0sCP=0.213±0.015±0.007, where the first uncertainties are statistical and the second systematic. Evidence for CP violation is found in the B0s→K+K− decay for the first time.

PhysicsParticle physicsLuminosity (scattering theory)PionMeson010308 nuclear & particles physicsOscillation0103 physical sciencesCP violation010306 general physics01 natural sciencesMeasure (mathematics)Physical Review D
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Measurements of the Λb0→J/ψΛ decay amplitudes and the Λb0 polarisation in pp collisions at s=7 TeV

2013

An angular analysis of Λ0b→J/ψΛ decays is performed using a data sample corresponding to 1.0 fb−1 collected in pp collisions at √s=7 TeV with the LHCb detector at the LHC. A parity violating asymmetry parameter characterising the Λ0b→J/ψΛ decay of 0.05±0.17±0.07 and a Λ0b transverse production polarisation of 0.06±0.07±0.02 are measured, where the first uncertainty is statistical and the second systematic.

PhysicsNuclear and High Energy PhysicsParticle physicsLarge Hadron Collider010308 nuclear & particles physicsmedia_common.quotation_subjectDetectorParity (physics)Astrophysics::Cosmology and Extragalactic AstrophysicsLambda01 natural sciences7. Clean energyHelicityAsymmetryNuclear physicsTransverse planeAmplitude0103 physical sciencesHigh Energy Physics::ExperimentAstrophysics::Earth and Planetary Astrophysics010306 general physicsmedia_commonPhysics Letters B
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Quantum numbers of theX(3872)state and orbital angular momentum in itsρ0J/ψdecay

2015

Angular correlations in B+→X(3872)K+ decays, with X(3872)→ρ0J/ψ, ρ0→π+π− and J/ψ→μ+μ−, are used to measure orbital angular momentum contributions and to determine the JPC value of the X(3872) meson. The data correspond to an integrated luminosity of 3.0 fb−1 of proton-proton collisions collected with the LHCb detector. This determination, for the first time performed without assuming a value for the orbital angular momentum, confirms the quantum numbers to be JPC=1++. The X(3872) is found to decay predominantly through S wave and an upper limit of 4% at 95% C.L. is set on the fraction of D wave.

Nuclear physicsPhysicsNuclear and High Energy PhysicsAngular momentumMesonTotal angular momentum quantum numberS-waveHigh Energy Physics::ExperimentQuantum numberMeasure (mathematics)X(3872)LuminosityPhysical Review D
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Study ofCPviolation inB∓→Dh∓(h=K,π) with the modesD→K∓π±π0,D→π+π−π0andD→K+K−π0

2015

An analysis of the decays of B--/+ -> DK -/+ and B--/+ -> D pi(-/+) is presented in which the D meson is reconstructed in the three-body final states K--/+pi(+/-)pi(0), pi(+)pi(-)pi(0) and K+K-pi(0). Using data from LHCb corresponding to an integrated luminosity of 3.0 fb(-1) of pp collisions, measurements of several CP observables are performed. First observations are obtained of the suppressed Atwood-Dunietz-Soni decay B--/+ -> [pi K-+(+/-)pi(0)](D)pi(-/+) and the quasi-Gronau-London-Wyler decay B--/+ -> [K+K-pi(0)](D)pi(-/+). The results are interpreted in the context of the unitarity triangle angle gamma and related parameters.

PhysicsNuclear and High Energy PhysicsParticle physicsUnitarity010308 nuclear & particles physicsContext (language use)01 natural sciencesLuminosityCrystallography0103 physical sciencesD mesonPiCP violation010306 general physicsPhysical Review D
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Observation of the rare B(s)(0) + decay from the combined analysis of CMS and LHCb data.

2015

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported licence.-- et al.

fundamental particleCompact Muon Solenoidstandard model flavor changing neutral currentsradioisotope decayB physicGaussian methodMU(+)MU(-)Temel Bilimler (SCI)rare decay [B/s0]Elementary particleATLAS DETECTOR12.15.MmÇOK DİSİPLİNLİ BİLİMLERRARE B-MESON DECAYS7000 GeV-cms8000 GeV-cmsSettore ING-INF/01 - Elettronica01 natural sciences7. Clean energyddc:0702 CHARGED LEPTONSscattering [p p]High energy physics ; Experimental particle physics ; LHC ; CMS ; Standard ModelQC[Anahtar Kelime Yok]Large Hadron ColliderMedicine (all); Multidisciplinarystandard3. Good healthHigh Energy Physics - PhenomenologyCERN LHC CollFIS/01 - FISICA SPERIMENTALEpriority journalHiggs bosonScience & Technology - Other TopicsPARTICLE PHYSICSmass spectrum [dimuon]Protonviolationcolliding beams [p p]physicschemical analyzerMesonModels beyond the standard modelprobabilitymesonelectromagnetic radiationB/s0 --> muon+ muon-Nuclear physicsbranching ratio: measured [B0]SEARCHLeptonic semileptonic and radiative decays of bottom mesonRARE B-MESON DECAYS; MINIMAL FLAVOR VIOLATION; LHC; CMS DETECTOR; LHCb DETECTOR; SEARCH; MU(+)MU(-); B-S(0); B-0;B-MESON DECAYS; MINIMAL FLAVOR VIOLATION; 2 CHARGED LEPTONS; ATLAS; DETECTOR; SEARCH; MU(+)MU(-); B-S(0); B-0; COLLIDER; PARTICLE010306 general physicsScience & TechnologyMuonMULTIDISCIPLINARY SCIENCES010308 nuclear & particles physicsBranching fractionMeson Bnull hypothesisDoğa Bilimleri GenelElementary particlesLARGE HADRON COLLIDERHEPp(p)over-bar collisionsNATURAL SCIENCES GENERALrare decay [B0]13.20.HeMINIMAL FLAVOR VIOLATIONchemical analysisprecisionB0 --> muon+ muon-Física de partículesExperimental particle physicsleptonic decay [B0]Physics::Instrumentation and DetectorsPhysics beyond the Standard ModelB-meson decays; p(p)over-bar collisions; branching fraction; root-s=1.96 tev; search; mu(+)mu(-); b-0; b-s(0); violation; modelsLarge Hadron Collider (LHC)High Energy Physics - ExperimentSettore FIS/04 - Fisica Nucleare e SubnucleareNeutral currentCOLLIDER[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]uncertainty12.60.-iFlavour Physicmass spectrometryPhysicsExperimental particleMultidisciplinaryCMSMedicine (all)Temel BilimlerSettore FIS/01 - Fisica SperimentaleB-meson decaysATLASLarge Hadron Collider beautybranching ratio: measured [B/s0]root-s=1.96 tevNatural Sciences (SCI)LHCNatural SciencesPARTICLEdata processingParticle Physics - Experimentchemical reactionParticle physicsbranching fractionNOPARTICLE PHYSICS; LARGE HADRON COLLIDER; CMS; LHCBmodelsLHCBExperimental particle; physics; data processing; electromagnetic field; electromagnetic radiation; fundamental particle; Gaussian method; physics; precision; chemical analysis; chemical analyzer; chemical reaction; elementary particle; Large Hadron Collider beauty; mass spectrometry; meson; null hypothesis; prediction; priority journal; probability; radioisotope decay; standard; uncertainty;B-MESON DECAYSelectromagnetic fieldTheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITYRare Decay0103 physical sciencesElectromagnetic fieldB-0elementary particleSDG 7 - Affordable and Clean EnergyDETECTORCompact Muon SolenoidMultidisipliner/dk/atira/pure/sustainabledevelopmentgoals/affordable_and_clean_energyLHCb DETECTORCMS LHC Meson B Rare DecayMinimal flavor violationpredictionLeptonsLHC-Bleptonic decay [B/s0]LHCbRare decayMedicine (all) MultidisciplinaryRARE B-MESON DECAYS; MINIMAL FLAVOR VIOLATION; LHC; CMS DETECTOR; LHCb DETECTOR; SEARCH; MU(+)MU(-); B-S(0); B-0B-S(0)[PHYS.HPHE]Physics [physics]/High Energy Physics - Phenomenology [hep-ph]High Energy Physics::ExperimentExperimentsexperimental resultsCMS DETECTOR
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Amplitude analysis ofB+→J/ψϕK+decays

2017

The first full amplitude analysis of B+→J/ψϕK+ with J/ψ→μ+μ−, ϕ→K+K− decays is performed with a data sample of 3 fb−1 of pp collision data collected at s√=7 and 8 TeV with the LHCb detector. The data cannot be described by a model that contains only excited kaon states decaying into ϕK+, and four J/ψϕ structures are observed, each with significance over 5 standard deviations. The quantum numbers of these structures are determined with significance of at least 4 standard deviations. The lightest is best described as a D±sD∗∓s cusp, but a resonant interpretation is also possible with mass consistent with, but width much larger than, previous measurements of the claimed X(4140) state. The mode…

Cusp (singularity)PhysicsParticle physics010308 nuclear & particles physicsState (functional analysis)Quantum number01 natural sciencesStandard deviationNuclear physicsAmplitudeExcited state0103 physical sciencesHigh Energy Physics::Experiment010306 general physicsSpin-½Physical Review D
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Constraints on the unitarity triangle angleγfrom Dalitz plot analysis ofB0→DK+π−decays

2016

The first study is presented of CP violation with an amplitude analysis of the Dalitz plot of B0→DK+π- decays, with D→K+π-, K+K-, and π+π-. The analysis is based on a data sample corresponding to 3.0 fb-1 of pp collisions collected with the LHCb detector. No significant CP violation effect is seen, and constraints are placed on the angle γ of the unitarity triangle formed from elements of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Hadronic parameters associated with the B0→DK∗(892)0 decay are determined for the first time. These measurements can be used to improve the sensitivity to γ of existing and future studies of the B0→DK∗(892)0 decay.

PhysicsParticle physicsFuture studiesUnitarity010308 nuclear & particles physicsCabibbo–Kobayashi–Maskawa matrixHadronDalitz plot01 natural sciencesNuclear physicsAmplitude0103 physical sciencesCP violation010306 general physicsPhysical Review D
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Measurement of the Difference of Time-IntegratedCPAsymmetries inD0→K−K+andD0→π−π+Decays

2016

A search for CP violation in $D^0 \rightarrow K^{-} K^{+} $ and $D^0 \rightarrow \pi^{-} \pi^{+} $ decays is performed using $pp$ collision data, corresponding to an integrated luminosity of $3~fb^{-1}$, collected using the LHCb detector at centre-of-mass energies of 7 and $8~$TeV. The flavour of the charm meson is inferred from the charge of the pion in $D^{*+}\rightarrow D^0\pi^+$ and $D^{*-}\rightarrow \bar{D^0}\pi^{-}$ decays. The difference between the CP asymmetries in $D^0 \rightarrow K^{-} K^{+} $ and $D^0 \rightarrow \pi^{-} \pi^{+} $ decays, $\Delta A_{CP} \equiv A_{CP}(K^{-} K^{+}) - A_{CP}(\pi^{-} \pi^{+})$, is measured to be $\left( -0.10 \pm 0.08(stat) \pm 0.03(syst) \right) \…

PhysicsParticle physicsMeson010308 nuclear & particles physicsmedia_common.quotation_subjectHigh Energy Physics::PhenomenologyGeneral Physics and AstronomyCharge (physics)01 natural sciencesAsymmetryLuminosityNuclear physicsPion0103 physical sciencesCP violationHigh Energy Physics::ExperimentCharm (quantum number)010306 general physicsmedia_commonPhysical Review Letters
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Measurement of the W boson mass

1996

The W boson mass is measured using proton-proton collision data at root s = 13 TeV corresponding to an integrated luminosity of 1.7fb(-1) recorded during 2016 by the LHCb experiment. With a simultaneous fit of the muon q/p(T) distribution of a sample of W ->mu y decays and the phi* distribution of a sample of Z -> mu mu decays the W boson mass is determined to be

13000 GeV-cmsTevatronparton: distribution functionQC770-798W: leptonic decay7. Clean energy01 natural sciencesLuminosityPhysics Particles & FieldsSubatomär fysikHadron-Hadron scattering (experiments)scattering [p p]Electroweak interactionNuclear Experimentparticle identification [muon]Settore FIS/01PhilosophyPhysicsCoupling (probability)CERN LHC CollHadron colliderPhysical SciencesTransverse masscolliding beams [p p]distribution function [parton]Collider Detector at FermilabParticles and fieldCOLLISIONSp p: scatteringCERN PBARP COLLIDERAstrophysics::High Energy Astrophysical PhenomenaW: mass: measuredStandard ModelNuclear physicsddc:530010306 general physics0206 Quantum PhysicsMuonScience & Technology010308 nuclear & particles physicsWeinberg angleHEPFERMILAB TEVATRONElectroweak interaction Hadron-Hadron scattering (experiments) QCD For- ward physicsCDFp p: colliding beamsPhysics::Instrumentation and DetectorsElectron–positron annihilation= 1.8 TEVGeneral Physics and Astronomy= 1.8 TEV; PBARP COLLISIONS; DECAYVector bosonHigh Energy Physics - ExperimentHigh Energy Physics - Experiment (hep-ex)Computer Science::Systems and ControlSubatomic Physics[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]PhysicFermilabBosonPhysics0105 Mathematical PhysicsStatistics::ApplicationsSettore FIS/01 - Fisica Sperimentalestatistical [error]Nuclear & Particles PhysicsCENTRAL TRACKING CHAMBERerror: statisticalCENTRAL ELECTROMAGNETIC CALORIMETERTransverse momentum0202 Atomic Molecular Nuclear Particle and Plasma PhysicsLHCmass: measured [W]Particle Physics - ExperimentStatistics::TheoryParticle physicsNuclear and High Energy Physicselectroweak interaction: precision measurementRegular Article - Experimental PhysicsTRANSVERSE ENERGYFOS: Physical sciencesmuon: particle identification530Particle decayPBARP COLLISIONSNuclear and particle physics. Atomic energy. Radioactivityprecision measurement [electroweak interaction]0103 physical sciencesForward physicVECTOR BOSONElectroweak interaction Hadron-Hadron scattering (experiments) QCD Forward physicsCERN PBARP COLLIDER; CENTRAL ELECTROMAGNETIC CALORIMETER; CENTRAL TRACKING CHAMBER; = 1.8 TEV; PARTON DISTRIBUTIONS; FERMILAB TEVATRON; VECTOR BOSON; TRANSVERSE ENERGY; CDF; COLLISIONShep-exHigh Energy Physics::PhenomenologyLHC-BQCDleptonic decay [W]LHCbPARTON DISTRIBUTIONSMass spectrumForward physicsPhysics::Accelerator PhysicsHigh Energy Physics::ExperimentDECAYHumanitiesexperimental results
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Amplitude analysis ofB−→D+π−π−decays

2016

The Dalitz plot analysis technique is used to study the resonant substructures of $B^{-} \to D^{+} \pi^{-} \pi^{-}$ decays in a data sample corresponding to 3.0 ${\rm fb}^{-1}$ of $pp$ collision data recorded by the LHCb experiment during 2011 and 2012. A model-independent analysis of the angular moments demonstrates the presence of resonances with spins 1, 2 and 3 at high $D^{+}\pi^{-}$ mass. The data are fitted with an amplitude model composed of a quasi-model-independent function to describe the $D^{+}\pi^{-}$ S-wave together with virtual contributions from the $D^{*}(2007)^{0}$ and $B^{*0}$ states, and components corresponding to the $D^{*}_{2}(2460)^{0}$, $D^{*}_{1}(2680)^{0}$, $D^{*}_…

PhysicsParticle physicsFormalism (philosophy of mathematics)AmplitudeSpinsMeson010308 nuclear & particles physicsScattering0103 physical sciencesDalitz plot010306 general physics01 natural sciencesPhysical Review D
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Observation of Bc+→J/ψD(*)K(*) decays

2017

A search for the decays B + c → J / ψ D ( * ) 0 K + and B + c → J / ψ D ( * ) + K * 0 is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3     fb − 1 . The decays B + c → J / ψ D 0 K + and B + c → J / ψ D * 0 K + are observed for the first time, while first evidence is reported for the B + c → J / ψ D * + K * 0 and B + c → J / ψ D + K * 0 decays. The branching fractions of these decays are determined relative to the B + c → J / ψ π + decay. The B + c mass is measured, using the J / ψ D 0 K + final state, to be 6274.28 ± 1.40 ( stat ) ± 0.32 ( syst )     MeV / c 2 . This is the most precise single measurement of the B + c mass to date.

PhysicsNuclear magnetic resonanceMeson010308 nuclear & particles physicsBranching fractionGenerator (category theory)0103 physical sciencesSingle measurementAnalytical chemistry010306 general physics01 natural sciencesLuminosityPhysical Review D
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Study of J/ψ Production in Jets

2017

The production of $J/\psi$ mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction of the jet transverse momentum carried by the $J/\psi$ meson, $z \equiv p_{\rm T}(J/\psi)/p_{\rm T}({\rm jet})$, is measured using jets with $p_{\rm T}({\rm jet}) > 20$ GeV in the pseudorapidity range $2.5 < \eta({\rm jet}) < 4.0$. The observed $z$ distribution for $J/\psi$ mesons produced in $b$-hadron decays is consistent with expectations. However, the results for prompt $J/\psi$ production do not agree with predictions based on fixed-order non-relativistic QCD. This is the first measurement o…

13000 GeV-cmsQuantum chromodynamics: Experimental testNuclear TheoryGeneral Physics and Astronomy01 natural sciences7. Clean energytransverse momentum [jet]Settore FIS/04 - Fisica Nucleare e SubnucleareHigh Energy Physics - ExperimentParticle production Quantum chromodynamicsddc:550scattering [p p][PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]LHCb - Abteilung HintonParticle productionNuclear ExperimentQuantum chromodynamicsPhysicsJet (fluid)Large Hadron Collider02 Physical SciencesHadron-induced high- and super-high-energy interactions (energy > 10 GeV): Inclusive production with identified hadronParticle physicsQuarkoniumPROMPTJ/psi mesonLeptonic semileptonic and radiative decays of J/ψ Υ and other quarkoniaCERN LHC Collhadroproduction [J/psi(3100)]Pseudorapidityrapidity [jet]root S=7 TEVPhysical SciencesLHCcolliding beams [p p]Particle Physics - ExperimentParticle physicsGeneral PhysicsMesonPSI(2S)Astrophysics::High Energy Astrophysical PhenomenaPhysics Multidisciplinarynonrelativistic [quantum chromodynamics]OCTET QUARKONIA PRODUCTIONNOJets in large-Q2 scatteringNuclear physicsOctet quarkonia production PP collision root S=7 TEV PSI(2S) physics prompt decayPHYSICSPhysics and Astronomy (all)OCTET QUARKONIA PRODUCTION; PP COLLISIONS; ROOT-S=7 TEV; PSI(2S); PHYSICS; PROMPT; DECAY0103 physical sciencesRapiditySDG 7 - Affordable and Clean Energy010306 general physics/dk/atira/pure/sustainabledevelopmentgoals/affordable_and_clean_energyScience & TechnologyPP COLLISIONSROOT-S=7 TEV010308 nuclear & particles physicsPP collisionhep-exHigh Energy Physics::PhenomenologyLHC-BHEPLHCbHigh Energy Physics::ExperimentHeavy quarkoniaFísica de partículesExperimentsDECAYQuantum chromodynamicsexperimental results
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Observation of the suppressed ADS modes B±→[π±K∓π+π−]DK± and B±→[π±K∓π+π−]Dπ±

2013

An analysis of and B-+/- -> DK +/- and B-+/- -> D pi(+/-) decays is presented where the D meson is reconstructed in the four-body final state K-+/-pi(-/+)pi(+)pi(-). Using LHCb data corresponding to an integrated luminosity of 1.0 fb(-1), first observations are made of the suppressed ADS modes B-+/- ->[pi K-+/-(-/+)pi(+)pi(-)](D)K-+/- and B +/- -> [pi K-+/-(-/+)pi(+)pi(-)](D)pi(+/-) with a significance of 5.1 sigma and greater than 10 sigma, respectively. Measurements of CP asymmetries and CP-conserving ratios of partial widths from this family of decays are also performed. The magnitude of the ratio between the suppressed and favoured B-+/- -> DK +/- amplitudes is determined to be r(B)(K) …

Nuclear physicsPhysicsNuclear and High Energy Physics010308 nuclear & particles physics0103 physical sciencesD mesonPiAnalytical chemistryCP violation010306 general physics01 natural sciencesPhysics Letters B
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Measurements of charm mixing and CP violation using D0→K±π∓ decays

2017

Measurements of charm mixing and CP violation parameters from the decay-time-dependent ratio of D0→K+π− to D0→K−π+ decay rates and the charge-conjugate ratio are reported. The analysis uses B¯¯¯¯→D∗+μ−X, and charge-conjugate decays, where D∗+→D0π+, and D0→K∓π±. The pp collision data are recorded by the LHCb experiment at center-of-mass energies s√ = 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb−1. The data are analyzed under three hypotheses: (i) mixing assuming CP symmetry, (ii) mixing assuming no direct CP violation in the Cabibbo-favored or doubly Cabibbo-suppressed decay amplitudes, and (iii) mixing allowing either direct CP violation and/or CP violation in the superpos…

PhysicsParticle physicsLuminosity (scattering theory)010308 nuclear & particles physicsHigh Energy Physics::PhenomenologyDisjoint sets01 natural sciencesNuclear physicsAmplitude0103 physical sciencesCP violationHigh Energy Physics::ExperimentCharm (quantum number)010306 general physicsMixing (physics)Eigenvalues and eigenvectorsPhysical Review D
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