arXiv subjects

P. d'Argent

Publications and source records attributed to P. d'Argent.

219 records · Page 13Linked to original sources

arXiv2015

Observation of $J/ψp$ resonances consistent with pentaquark states in ${Λ_b^0\to J/ψK^-p}$ decays

Observations of exotic structures in the $J/ψp$ channel, that we refer to as pentaquark-charmonium states, in $Λ_b^0\to J/ψK^- p$ 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 $4380\pm 8\pm 29$ MeV and a width of $205\pm 18\pm 86$ MeV, while the second is narrower, with a mass of $4449.8\pm 1.7\pm 2.5$ MeV and a width of $39\pm 5\pm 19$ MeV. The preferred $J^P$ assignments are of opposite parity, with one state having spin 3/2 and the other 5/2.

hep-ex↗

arXiv2015

Identification of beauty and charm quark jets at LHCb

Identification of jets originating from beauty and charm quarks is important for measuring Standard Model processes and for searching for new physics. The performance of algorithms developed to select $b$- and $c$-quark jets is measured using data recorded by LHCb from proton-proton collisions at $\sqrt{s}=7$ TeV in 2011 and at $\sqrt{s}=8$ TeV in 2012. The efficiency for identifying a $b(c)$ jet is about 65%(25%) with a probability for misidentifying a light-parton jet of 0.3% for jets with transverse momentum $p_{\rm T} > 20$ GeV and pseudorapidity $2.2 < η< 4.2$. The dependence of the performance on the $p_{\rm T}$ and $η$ of the jet is also measured.

hep-ex↗

arXiv2015

A study of $CP$ violation in $B^\mp \rightarrow Dh^\mp$ ($h=K,π$) with the modes $D \rightarrow K^\mp π^\pm π^0$, $D \rightarrow π^+π^-π^0$ and $D \rightarrow K^+K^-π^0$

An analysis of the decays of $B^\mp \rightarrow D K^\mp$ and $B^\mp \rightarrow D π^\mp $ is presented in which the $D$ meson is reconstructed in the three-body final states $K^\mp π^\pm π^0$, $π^+ π^- π^0$ and $K^+ K^- π^0$. 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 ADS decay $B^\mp \rightarrow [π^\mp K^\pm π^0]_D π^\mp$ and the quasi-GLW decay $B^\mp \rightarrow [K^+ K^- π^0]_D π^\mp$. The results are interpreted in the context of the unitarity triangle angle $γ$ and related parameters.

hep-ex↗