A5031683177- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Particle Detector Development and Performance
- Particle Accelerators and Free-Electron Lasers
- Black Holes and Theoretical Physics
- Medical Imaging Techniques and Applications
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Cosmology and Gravitation Theories
- Stochastic processes and statistical mechanics
- Advanced NMR Techniques and Applications
- Astrophysics and Cosmic Phenomena
- Distributed and Parallel Computing Systems
- International Science and Diplomacy
- Radiation Detection and Scintillator Technologies
- Particle accelerators and beam dynamics
- Algorithms and Data Compression
- Cold Atom Physics and Bose-Einstein Condensates
- Radioactive Decay and Measurement Techniques
- Muon and positron interactions and applications
European Organization for Nuclear Research
2010-2025
Institute of High Energy Physics
2020-2025
Universitat Ramon Llull
2023-2024
Institute for High Energy Physics
2014-2023
Kurchatov Institute
2019-2023
RWTH Aachen University
2023
Korea Institute of Science & Technology Information
2023
Universitat de Barcelona
2023
Petersburg Nuclear Physics Institute
2011-2021
Campbell Collaboration
2012-2021
A measurement of the ratio branching fractions $B^{+}\rightarrow K^{+}\mu^{+}\mu^{-}$ and K^{+}e^{+}e^{-}$ decays is presented using proton-proton collision data, corresponding to an integrated luminosity 3.0 fb$^{-1}$, recorded with LHCb experiment at center-of-mass energies 7 8 $\mathrm{\,Te\kern -0.1em V}$. The value for dilepton invariant mass squared range $1<q^{2}<6\mathrm{\,Ge\kern V^2\!/}c^4$ measured be $0.745^{+0.090}_{-0.074}\mathrm{\,(stat)}\,\pm0.036\mathrm{\,(syst)}$. This most...
The cross section for ee+ e- → π+ π- J/ψ between 3.8 and 5.5 GeV is measured with a 967 fb(-1) data sample collected by the Belle detector at or near Υ(nS) (n = 1,2,…,5) resonances. Y(4260) state observed, its resonance parameters are determined. In addition, an excess of production around 4 observed. This feature can be described Breit-Wigner parametrization properties that consistent Y(4008) was previously reported Belle. study decays, structure observed in M(π(±)J/ψ) mass spectrum 5.2σ...
The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) CERN. experiment designed for precision measurements of CP violation and rare decays beauty charm hadrons. In this paper performance various sub-detectors trigger system are described, using data taken from 2010 to 2012. It shown that design criteria have been met. excellent has allowed collaboration publish wide range physics results, demonstrating LHCb's unique role, both as heavy flavour general purpose in region.
A narrow pentaquark state, P_{c}(4312)^{+}, decaying to J/ψp, is discovered with a statistical significance of 7.3σ in data sample Λ_{b}^{0}→J/ψpK^{-} decays, which an order magnitude larger than that previously analyzed by the LHCb Collaboration. The P_{c}(4450)^{+} structure formerly reported confirmed and observed consist two overlapping peaks, P_{c}(4440)^{+} P_{c}(4457)^{+}, where this two-peak interpretation 5.4σ. proximity Σ_{c}^{+}D[over ¯]^{0} ¯]^{*0} thresholds peaks suggests they...
We report the observation of two narrow structures in mass spectra pi+-Y(nS) (n=1,2,3) and pi+-hb(mP)(m$ (m=1,2) pairs that are produced association with a single charged pion Y(5S) decays. The measured masses widths averaged over five final states M_1=(10607.2+-2.0) MeV/c2, Gamma_1=(18.4+-2.4) MeV M_2=(10652.2+-1.5) Gamma_2=(11.5+-2.2) MeV. results obtained 121.4 1/fb data sample collected Belle detector vicinity resonance at KEKB asymmetric-energy e+e- collider.
We present a measurement of form-factor-independent angular observables in the decay ${B}^{0}\ensuremath{\rightarrow}{K}^{*}(892{)}^{0}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. The analysis is based on data sample corresponding to an integrated luminosity $1.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, collected by LHCb experiment $pp$ collisions at center-of-mass energy 7 TeV. Four are measured six bins dimuon invariant mass squared ${q}^{2}$ range...
A test of lepton universality, performed by measuring the ratio branching fractions $B^{0} \rightarrow K^{*0}\mu^{+}\mu^{-}$ and K^{*0}e^{+}e^{-}$ decays, $R_{K^{*0}}$, is presented. The $K^{*0}$ meson reconstructed in final state $K^{+}\pi^{-}$, which required to have an invariant mass within 100$\mathrm{\,MeV}c^2$ known $K^{*}(892)^{0}$ mass. analysis using proton-proton collision data, corresponding integrated luminosity about 3$\mathrm{\,fb}^{-1}$, collected LHCb experiment at...
A highly significant structure is observed in the $\Lambda_c^+K^-\pi^+\pi^+$ mass spectrum, where $\Lambda_c^+$ baryon reconstructed decay mode $pK^-\pi^+$. The consistent with originating from a weakly decaying particle, identified as doubly charmed $\Xi_{cc}^{++}$. difference between masses of $\Xi_{cc}^{++}$ and states measured to be $1334.94 \pm 0.72 (\mathrm{stat}) 0.27 (\mathrm{syst}~\mathrm{MeV}/c^2$, then determined $3621.40 (\mathrm{syst} 0.14 \, (\Lambda_c^+)~\mathrm{MeV}/c^2$,...
A measurement of the ratio branching fractions decays B^{+}→K^{+}μ^{+}μ^{-} and B^{+}→K^{+}e^{+}e^{-} is presented. The proton-proton collision data used correspond to an integrated luminosity 5.0 fb^{-1} recorded with LHCb experiment at center-of-mass energies 7, 8, 13 TeV. For dilepton mass-squared range 1.1<q^{2}<6.0 GeV^{2}/c^{4} measured be R_{K}=0.846_{-0.054}^{+0.060}_{-0.014}^{+0.016}, where first uncertainty statistical second systematic. This most precise R_{K} date compatible...
Resonant structures in B^{0}→ψ^{'}π^{-}K^{+} decays are analyzed by performing a four-dimensional fit of the decay amplitude, using pp collision data corresponding to 3 fb^{-1} collected with LHCb detector. The cannot be described K^{+}π^{-} resonances alone, which is confirmed model-independent approach. A highly significant Z(4430)^{-}→ψ^{'}π^{-} component required, thus confirming existence this state. observed evolution Z(4430)^{-} amplitude ψ^{'}π^{-} mass establishes resonant nature...
A search for the rare decays ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ is performed with data collected in 2011 2012 LHCb experiment at Large Hadron Collider. The samples comprise $1.1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of proton-proton collisions $\sqrt{s}=8\text{ }\mathrm{TeV}$ $1.0\text{ $\sqrt{s}=7\text{ }\mathrm{TeV}$. We...
The quantum numbers of the X(3872) meson are determined to be JPC = 1++ based on angular correlations in B+ K+ decays, where pi+pi- J/psi and \mu+\mu-. data correspond 1.0 fb-1 pp collisions collected by LHCb detector. only alternative assignment allowed previous measurements, JPC=2-+, is rejected with a confidence level equivalent more than eight Gaussian standard deviations using likelihood-ratio test full phase space. This result favors exotic explanations state.
Abstract The standard model of particle physics currently provides our best description fundamental particles and their interactions. theory predicts that the different charged leptons, electron, muon tau, have identical electroweak interaction strengths. Previous measurements shown a wide range decays are consistent with this principle lepton universality. This article presents evidence for breaking universality in beauty-quark decays, significance 3.1 deviations, based on proton–proton...
The production of J/psi mesons in proton-proton collisions at sqrt(s)=7 TeV is studied with the LHCb detector LHC. differential cross-section for prompt measured as a function transverse momentum pT and rapidity y fiducial region 0<pT<14 GeV/c 2.0<y<4.5. fraction from b-hadron decays are also same ranges. analysis based on data sample corresponding to an integrated luminosity 5.2pb-1. cross-sections over 10.52 +/- 0.04 1.40 +1.64/-2.20 mub 1.14 0.01 0.16 decays, where first uncertainty...
The ratio of branching fractions R(D*−)≡B(B0→D*−τ+ντ)/B(B0→D*−μ+νμ) is measured using a data sample proton-proton collisions collected with the LHCb detector at center-of-mass energies 7 and 8 TeV, corresponding to an integrated luminosity 3 fb−1. For first time, R(D*−) determined τ-lepton decays three charged pions in final state. B0→D*−τ+ντ yield normalized that B0→D*−π+π−π+ mode, providing measurement B(B0→D*−τ+ντ)/B(B0→D*−π+π−π+)=1.97±0.13±0.18, where uncertainty statistical second...
Using proton-proton collision data at centre-of-mass energies of $\sqrt{s} = 7$, $8$ and $13\mathrm{\,TeV}$ recorded by the LHCb experiment Large Hadron Collider, corresponding to an integrated luminosity $9\mathrm{\,fb}^{-1}$, invariant mass spectrum $J/ψ$ pairs is studied. A narrow structure around $6.9\mathrm{\,GeV/}c^2$ matching lineshape a resonance broad just above twice are observed. The deviation from nonresonant $J/ψ$-pair production five standard deviations in region between $6.2$...
The ratio of branching fractions ${\cal{R}}(D^{*-})\equiv {\cal{B}}(B^0 \to D^{*-} τ^+ ν_τ)/{\cal{B}}(B^0 μ^+ν_μ)$ is measured using a data sample proton-proton collisions collected with the LHCb detector at center-of-mass energies 7 and 8 TeV, corresponding to an integrated luminosity 3$~$fb$^{-1}$. $τ$ lepton reconstructed three charged pions in final state. A novel method used that exploits different vertex topologies signal backgrounds isolate samples semitauonic decays $b$ hadrons high...
A search for the rare decays ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ and ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$ is performed at LHCb experiment. The data analyzed correspond to an integrated luminosity of $1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ $pp$ collisions a center-of-mass energy 7 TeV $2\text{ 8 TeV. An excess signal candidates with respect background expectation seen...
The $\Xi_c^+ K^-$ mass spectrum is studied with a sample of $pp$ collision data corresponding to an integrated luminosity 3.3 fb$^{-1}$, collected by the LHCb experiment. $\Xi_c^+$ reconstructed in decay mode $p K^- \pi^+$. Five new, narrow excited $\Omega_c^0$ states are observed: $\Omega_c(3000)^0$, $\Omega_c(3050)^0$, $\Omega_c(3066)^0$, $\Omega_c(3090)^0$, and $\Omega_c(3119)^0$. Measurements their masses widths reported.
Abstract Conventional, hadronic matter consists of baryons and mesons made three quarks a quark–antiquark pair, respectively 1,2 . Here, we report the observation state containing four in Large Hadron Collider beauty experiment. This so-called tetraquark contains two charm quarks, $$\overline{{{{{u}}}}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mrow> <mml:mi>u</mml:mi> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> </mml:math> $$\overline{{{{{d}}}}}$$...
A search for the rare decays B_{s}^{0}→μ^{+}μ^{-} and B^{0}→μ^{+}μ^{-} is performed at LHCb experiment using data collected in pp collisions corresponding to a total integrated luminosity of 4.4 fb^{-1}. An excess observed with significance 7.8 standard deviations, representing first observation this decay single experiment. The branching fraction measured be B(B_{s}^{0}→μ^{+}μ^{-})=(3.0±0.6_{-0.2}^{+0.3})×10^{-9}, where uncertainty statistical second systematic. measurement effective...
The LHCb Upgrade II will fully exploit the flavour-physics opportunities of HL-LHC, and study additional physics topics that take advantage forward acceptance spectrometer. I begin operation in 2020. Consolidation occur, modest enhancements detector be installed, Long Shutdown 3 LHC (2025) these are discussed here. main installed long shutdown 4 (2030) build on strengths current experiment I. It operate at a luminosity up to $ 2 \times 10^{34} \rm cm^{-2}s^{-1}$, ten times detector. New...
A measurement is reported of the ratio branching fractions R(J/ψ)=B(B_{c}^{+}→J/ψτ^{+}ν_{τ})/B(B_{c}^{+}→J/ψμ^{+}ν_{μ}), where τ^{+} lepton identified in decay mode τ^{+}→μ^{+}ν_{μ}ν[over ¯]_{τ}. This analysis uses a sample proton-proton collision data corresponding to 3.0 fb^{-1} integrated luminosity recorded with LHCb experiment at center-of-mass energies 7 and 8 TeV. signal found for B_{c}^{+}→J/ψτ^{+}ν_{τ} significance 3 standard deviations corrected systematic uncertainty, measured be...
An angular analysis of the $B^{0}\rightarrow K^{*0}(\to K^{+}\pi^{-})\mu^{+}\mu^{-}$ decay is presented using a data set corresponding to an integrated luminosity 4.7 fb$^{-1}$ $pp$ collision collected with LHCb experiment. The full $C\!P$-averaged observables are determined in bins invariant mass squared dimuon system. Contamination from decays $K^{+}\pi^{-}$ system S-wave configuration taken into account. tension seen between previous results and Standard Model predictions persists new...