A5106443479- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Advanced Data Storage Technologies
- Cosmology and Gravitation Theories
- Particle Accelerators and Free-Electron Lasers
University of Oxford
2017-2023
Centro Brasileiro de Pesquisas Físicas
2017
University of Copenhagen
2016
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...
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...
An improved measurement of the decay B0s→μ+μ− and searches for decays B0→μ+μ− B0s→μ+μ−γ are performed at LHCb experiment using data collected in proton-proton collisions √s=7, 8 13 TeV, corresponding to integrated luminosities 1, 2 6 fb−1, respectively. The branching fraction effective lifetime measured be B(B0s→μ+μ−)=(3.09+0.46+0.15−0.43−0.11)×10−9 τ(B0s→μ+μ−)=(2.07±0.29±0.03) ps, respectively, where uncertainties include both statistical systematic contributions. No significant signal is...
An amplitude analysis of flavor-untagged B_{s}^{0}→J/ψpp[over ¯] decays is performed using a sample 797±31 reconstructed with the LHCb detector. The data, collected in proton-proton collisions between 2011 and 2018, correspond to an integrated luminosity 9 fb^{-1}. Evidence for new structure J/ψp J/ψp[over systems mass 4337_{-4}^{+7} _{-2}^{+2} MeV width 29_{-12}^{+26} _{-14}^{+14} found, where first uncertainty statistical second systematic, significance range 3.1 3.7σ, depending on...
The first measurement of heavy-flavor production by the LHCb experiment in its fixed-target mode is presented. J/ψ and D^{0} mesons studied with beams protons different energies colliding gaseous targets helium argon nucleon-nucleon center-of-mass sqrt[s_{NN}]=86.6 110.4 GeV, respectively. cross sections pHe collisions rapidity range [2, 4.6] are found to be σ_{J/ψ}=652±33(stat)±42(syst) nb/nucleon σ_{D^{0}}=80.8±2.4(stat)±6.3(syst) μb/nucleon, where uncertainty statistical second...
We calculate the double pole contribution to two four fermion scattering through W ± currents at tree level in Standard Model Effective Field Theory (SMEFT). assume all fermions be massless, U(3)5 flavour and CP symmetry. Using this result, we update global constraint picture on SMEFT parameters including LEPII data these charged current processes, also modifications our fit procedure motivated by a companion paper focused mass extractions. The reported is now 177 observables emphasises need...
A bstract The decay-time-dependent CP asymmetry in B 0 → D ∗± ∓ decays is mea- sured using a data set corresponding to an integrated luminosity of 9 fb − 1 recorded by the LHCb detector proton-proton collisions at centre-of-mass energies 7, 8 and 13 TeV. parameters are measured as $$ {\displaystyle \begin{array}{c}{S}_{D\ast D}=-0.861\pm 0.077\left(\mathrm{stat}\right)\pm 0.019\left(\mathrm{syst}\right),\\ {}\varDelta {S}_{D\ast D}=0.019\pm 0.075\left(\mathrm{stat}\right)\pm...
A measurement of mixing and CP violation in neutral charm mesons is performed using data reconstructed proton-proton collisions collected by the LHCb experiment from 2016 to 2018, corresponding an integrated luminosity 5.4 fb^{-1}. total 30.6 million D^{0}→K_{S}^{0}π^{+}π^{-} decays are analyzed a method optimized for mass difference between charm-meson eigenstates. Allowing interference decay, decay-width differences measured be x_{CP}=[3.97±0.46(stat)±0.29(syst)]×10^{-3}...
Results are reported from a search for the rare decays ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\mu}}^{\ensuremath{\mp}}$ and ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\mu}}^{\ensuremath{\mp}}$, where $\ensuremath{\tau}$ lepton is reconstructed in channel...
A bstract An angular analysis of the B 0 → K* e + − decay is performed using a data sample corresponding to an integrated luminosity 9 fb 1 pp collisions collected with LHCb experiment. The conducted in very low dielectron mass squared ( q 2 ) interval between . 0008 and 257 GeV , where rate dominated by K * γ transition virtual photon. fraction longitudinal polarisation meson, F L measured be = (4 4 ± 6 4)%, first uncertainty statistical second systematic. $$ {A}_{\mathrm{T}}^{\mathrm{Re}}...
We report a measurement of the lifetime $\Omega_c^0$ baryon using proton-proton collision data at center-of-mass energies 7 and 8~TeV, corresponding to an integrated luminosity 3.0 fb$^{-1}$ collected by LHCb experiment. The sample consists about 1000 $\Omega_b^-\to\Omega_c^0\mu^-\bar{\nu}_{\mu} X$ signal decays, where is detected in $pK^-K^-\pi^+$ final state $X$ represents possible additional undetected particles decay. measured be $\tau_{\Omega_c^0} = 268\pm24\pm10\pm2$ fs, uncertainties...
Measurements of the $W^\pm$ mass ($m_W$) provide an important consistency check Standard Model (SM) and constrain possibility physics beyond SM. Precision measurements $m_W$ at hadron colliders are inferred from kinematic distributions transverse variables. We examine how this inference is modified when considering presence SM expressed in terms local contact operators. show that Tevatron using variables transparent applicable as consistent constraints Effective Field Theory (SMEFT) with...
A bstract The $$ {\varXi}_{cc}^{++}\to {\varXi}_c^{\prime +}{\pi}^{+} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>Ξ</mml:mi> <mml:mi>cc</mml:mi> <mml:mrow> <mml:mo>+</mml:mo> </mml:mrow> </mml:msubsup> <mml:mo>→</mml:mo> <mml:mi>c</mml:mi> <mml:mo>′</mml:mo> <mml:msup> <mml:mi>π</mml:mi> </mml:msup> </mml:math> decay is observed using proton-proton collisions collected by the LHCb experiment at a centre-of-mass energy of 13 TeV, corresponding to an...
The production rate of B_{s}^{0} mesons relative to B^{0} is measured by the LHCb experiment in pp collisions at a center-of-mass energy sqrt[s]=13 TeV over forward rapidity interval 2<y<4.5 as function charged particle multiplicity event. Evidence 3.4σ level found for an increase ratio cross sections with transverse momenta below 6 GeV/c, no significant dependence higher momentum. Comparison data from e^{+}e^{-} implies that density hadronic medium may affect rates B mesons. This...
Measurements of $CP$ observables in $B^\pm \rightarrow D^{(*)} K^\pm$ and \pi^\pm$ decays are presented, where $D^{(*)}$ indicates a neutral $D$ or $D^*$ meson that is an admixture $D^{(*)0}$ $\bar{D}^{(*)0}$ states. Decays the to $D\pi^0$ $D\gamma$ final states partially reconstructed without inclusion pion photon, resulting distinctive shapes $B$ candidate invariant mass distribution. fully $K^\pm \pi^\mp$, $K^+ K^-$ $\pi^+ \pi^-$ The analysis uses sample charged mesons produced $pp$...
A bstract search for the decay $$ {B}_S^0\to {\overline{K}}^{\ast 0}{\mu}^{+}{\mu}^{-} <mml:math...
The first measurement of the production rate ${\mathrm{\ensuremath{\Xi}}}_{b}^{\ensuremath{-}}$ baryons in $pp$ collisions relative to that ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}$ is reported, using data samples collected by LHCb experiment, and corresponding integrated luminosities 1, 2 $1.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ at $\sqrt{s}=7$, 8 13 TeV, respectively. In kinematic region $2<\ensuremath{\eta}<6$ ${p}_{\mathrm{T}}<20\text{ }\mathrm{GeV}/c$, we measure...
A bstract The decays $$ {\mathrm{B}}_{\mathrm{s}}^0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup></mml:math> → J / ψπ + π − K are studied using a data set corresponding to an integrated luminosity of 9 fb 1 , collected with the LHCb detector in proton-proton collisions at centre-of-mass energies 7, 8 and 13 TeV. \mathrm{J}/{\uppsi \mathrm{K}}^{\ast 0}{\overline{\mathrm{K}}}^{\ast 0}...
A four-body amplitude analysis of the ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}^{*+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay is performed, where fractions and relative phases various resonances contributing to are measured. Several quasi-model-independent analyses performed aimed at searching for presence new states establishing quantum numbers previously observed charmed meson resonances. In particular resonance parameters determined...
A bstract Forward top quark pair production is studied in pp collisions the μeb final state using a data sample corresponding to an integrated luminosity of 1.93 fb −1 collected with LHCb experiment at centre-of-mass energy 13 TeV. The cross-section measured fiducial region where both leptons have transverse momentum greater than 20 GeV and pseudorapidity between 2.0 4.5. quadrature sum azimuthal separation difference pseudorapidities, denoted Δ R , two must be larger 0.1. b -jet axis...
A time-dependent analysis of the B_{s}^{0}→ϕγ decay rate is performed to determine CP -violating observables S_{ϕγ} and C_{ϕγ} mixing-induced observable A_{ϕγ}^{Δ}. The measurement based on a sample pp collision data recorded with LHCb detector, corresponding an integrated luminosity 3 fb^{-1} at center-of-mass energies 7 8 TeV. measured values are S_{ϕγ}=0.43±0.30±0.11, C_{ϕγ}=0.11±0.29±0.11, A_{ϕγ}^{Δ}=-0.67_{-0.41}^{+0.37}±0.17, where first uncertainty statistical second systematic. This...
A measurement of the charm-mixing parameter y_{CP} using D^{0}→K^{+}K^{-}, D^{0}→π^{+}π^{-}, and D^{0}→K^{-}π^{+} decays is reported. The D^{0} mesons are required to originate from semimuonic B^{-} B[over ¯]^{0} mesons. These partially reconstructed in a data set proton-proton collisions at center-of-mass energies 7 8 TeV collected with LHCb experiment corresponding an integrated luminosity 3 fb^{-1}. measured be (0.57±0.13(stat)±0.09(syst))%, agreement with, as precise as, current...
A search for $CP$ violation in the ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ decay is performed using LHCb data corresponding to an integrated luminosity of $6.6\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ collected $pp$ collisions at center-of-mass energies 7, 8 and 13 TeV. The analysis uses both triple product asymmetries unbinned energy test method. highest...
A bstract Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb − 1 collected with the LHCb detector, seven decay modes $$ {\mathrm{B}}_{\mathrm{c}}^{+} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>c</mml:mi><mml:mo>+</mml:mo></mml:msubsup></mml:math> meson into a J / ψ or ψ(2S) and three charged hadrons, kaons pions, are studied. The decays → (ψ(2S) ψπ + π )π , ψ(2S)π ψK K observed for first time, evidence...
A bstract Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb −1 , collected with the LHCb detector between 2011 and 2018, a new narrow charmonium state, X(3842) resonance, is observed in decay modes $$ \mathrm{X}(3842)\to {D}^0{\overline{D}}^0 <mml:math...