Abstract The cross-sections of $$\psi {(2S)}$$ ψ(2S) meson production in proton-proton collisions at $$\sqrt{s} =13\text { TeV} $$ s=13TeV are measured with a data sample collected by the LHCb ...detector corresponding to an integrated luminosity of $$275\text { pb} ^{-1} $$ 275pb-1 . The production cross-sections for prompt $$\psi {(2S)}$$ ψ(2S) mesons and those for $$\psi {(2S)}$$ ψ(2S) mesons from b-hadron decays ($${\psi {(2S)}} \text{-from- }{b} $$ ψ(2S)-from-b ) are determined as functions of the transverse momentum, $$p_{\mathrm {T}}$$ pT , and the rapidity, y, of the $$\psi {(2S)}$$ ψ(2S) meson in the kinematic range $$2<p_{\mathrm {T}} <20\text { GeV/}c $$ 2<pT<20GeV/c and $$2.0<y<4.5$$ 2.0<y<4.5 . The production cross-sections integrated over this kinematic region are $$\begin{aligned} \begin{aligned}&\sigma (\text{ prompt } {\psi {(2S)}},13\text { TeV})\\&\quad =1.430\pm 0.005\text { (stat)} \pm 0.099\text { (syst)} \,\upmu \text {b} ,\\&\sigma ({\psi {(2S)}} \text{-from- }{b},13\text { TeV})\\&\quad =0.426\pm 0.002\text { (stat)} \pm 0.030\text { (syst)} \,\upmu \text {b} . \end{aligned} \end{aligned}$$ σ(promptψ(2S),13TeV)=1.430±0.005(stat)±0.099(syst)μb,σ(ψ(2S)-from-b,13TeV)=0.426±0.002(stat)±0.030(syst)μb. A new measurement of $$\psi {(2S)}$$ ψ(2S) production cross-sections in pp collisions at $$\sqrt{s}=7\text { TeV} $$ s=7TeV is also performed using data collected in 2011, corresponding to an integrated luminosity of $$614\text { pb} ^{-1} $$ 614pb-1 . The integrated production cross-sections in the kinematic range $$3.5<p_{\mathrm {T}} <14\text { GeV/}c $$ 3.5<pT<14GeV/c and $$2.0<y<4.5$$ 2.0<y<4.5 are $$\begin{aligned} \begin{aligned}&\sigma (\text{ prompt } {\psi {(2S)}},7\text { TeV})\\&\quad =0.471\pm 0.001\text { (stat)} \pm 0.025\text { (syst)} \,\upmu \text {b} ,\\&\sigma ({\psi {(2S)}} \text{-from- }{b},7\text { TeV})\\&\quad =0.126\pm 0.001\text { (stat)} \pm 0.008\text { (syst)} \,\upmu \text {b} . \end{aligned} \end{aligned}$$ σ(promptψ(2S),7TeV)=0.471±0.001(stat)±0.025(syst)μb,σ(ψ(2S)-from-b,7TeV)=0.126±0.001(stat)±0.008(syst)μb. All results show reasonable agreement with theoretical calculations.
A search for Formula omitted violation in charmless four-body decays of Formula omitted and Formula omitted baryons with a proton and three charged mesons in the final state is performed. To cancel ...out production and detection charge-asymmetry effects, the search is carried out by measuring the difference between the Formula omitted asymmetries in a charmless decay and in a decay with an intermediate charmed baryon with the same particles in the final state. The data sample used was recorded in 2011 and 2012 with the LHCb detector and corresponds to an integrated luminosity of Formula omitted. A total of 18 Formula omitted asymmetries are considered, either accounting for the full phase space of the decays or exploring specific regions of the decay kinematics. No significant Formula omitted-violation effect is observed in any of the measurements.
Abstract A search for $$C\!P$$ CP violation in charmless four-body decays of $${\varLambda } ^0_{b} $$ Λb0 and $${\varXi } ^0_{b} $$ Ξb0 baryons with a proton and three charged mesons in the final ...state is performed. To cancel out production and detection charge-asymmetry effects, the search is carried out by measuring the difference between the $$C\!P$$ CP asymmetries in a charmless decay and in a decay with an intermediate charmed baryon with the same particles in the final state. The data sample used was recorded in 2011 and 2012 with the LHCb detector and corresponds to an integrated luminosity of $$3 \text { fb} ^{-1} $$ 3fb-1 . A total of 18 $$C\!P$$ CP asymmetries are considered, either accounting for the full phase space of the decays or exploring specific regions of the decay kinematics. No significant $$C\!P$$ CP -violation effect is observed in any of the measurements.
Search for the rare decay [Formula omitted] Aaij, R; Beteta, C. Abellán; Adeva, B ...
The European physical journal. C, Particles and fields,
08/2019, Letnik:
79, Številka:
8
Journal Article
Recenzirano
Odprti dostop
A search for the rare leptonic decay Formula omitted is performed using proton-proton collision data corresponding to an integrated luminosity of Formula omitted collected by the LHCb experiment. The ...search is carried out in the region where the lowest of the two Formula omitted mass combinations is below Formula omitted. The data are consistent with the background-only hypothesis and an upper limit of Formula omitted at 95% confidence level is set on the branching fraction in the stated kinematic region.
Abstract A search for the rare leptonic decay $${{{B} ^+}} \!\rightarrow {\mu ^+} {\mu ^-} {\mu ^+} {{\upnu } _\mu } $$ B+→μ+μ-μ+νμ is performed using proton-proton collision data corresponding to an ...integrated luminosity of $$4.7 \, {\hbox {fb}}^{-1}$$ 4.7fb-1 collected by the LHCb experiment. The search is carried out in the region where the lowest of the two $${\mu ^+\mu ^-} $$ μ+μ- mass combinations is below $$980 {\mathrm {\,MeV\!/}c^2} $$ 980MeV/c2 . The data are consistent with the background-only hypothesis and an upper limit of $$1.6 \times 10^{-8}$$ 1.6×10-8 at 95% confidence level is set on the branching fraction in the stated kinematic region.
A search for CP violation in Λb0→pK− and Λb0→pπ− decays is presented using a sample of pp collisions collected with the LHCb detector and corresponding to an integrated luminosity of 3.0fb−1. The CP ...-violating asymmetries are measured to be ACPpK−=−0.020±0.013±0.019 and ACPpπ−=−0.035±0.017±0.020, and their difference ACPpK−−ACPpπ−=0.014±0.022±0.010, where the first uncertainties are statistical and the second systematic. These are the most precise measurements of such asymmetries to date.
The branching fraction and direct Formula omitted asymmetry of the decay Formula omitted are measured using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of ...7 and 8 TeV, corresponding to a total integrated luminosity of 3 Formula omitted. The following results are obtained: B(B+right arrowJ/psirho+)=(3.81-0.24+0.25±0.35)x10-5,ACP(B+right arrowJ/psirho+)=-0.045-0.057+0.056±0.008,where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.
Abstract The branching fraction and direct $$C\!P$$ CP asymmetry of the decay $${{{B} ^+}} \!\rightarrow {{J /\psi }} {{\rho } ^+} $$ B+→J/ψρ+ are measured using proton-proton collision data ...collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to a total integrated luminosity of 3$$\,\text{ fb }^{-1}$$ fb-1 . The following results are obtained: $$\begin{aligned} \mathcal {B}({{B} ^+} \!\rightarrow {{J /\psi }} {{\rho } ^+} )&= (3.81^{+0.25}_{-0.24} \pm 0.35) \times 10^{-5},\\ \mathcal {A}^{{C\!P}} ({{B} ^+} \!\rightarrow {{J /\psi }} {{\rho } ^+} )&= -0.045^{+0.056}_{-0.057} \pm 0.008, \end{aligned}$$ B(B+→J/ψρ+)=(3.81-0.24+0.25±0.35)×10-5,ACP(B+→J/ψρ+)=-0.045-0.057+0.056±0.008, where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.
A search is made for the highly-suppressed B meson decays B+→K+K+π− and B+→π+π+K− using a data sample corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb experiment in ...proton–proton collisions at centre-of-mass energies of 7 and 8 TeV. No evidence is found for the decays, and upper limits at 90% confidence level are determined to be B(B+→K+K+π−)<1.1×10−8 and B(B+→π+π+K−)<4.6×10−8.
The decay Λb0→Λc+pp‾π− is observed using pp collision data collected with the LHCb detector at centre-of-mass energies of s=7 and 8 Tev, corresponding to an integrated luminosity of 3 fb−1. The ratio ...of branching fractions between Λb0→Λc+pp‾π− and Λb0→Λc+π− decays is measured to beB(Λb0→Λc+pp‾π−)B(Λb0→Λc+π−)=0.0540±0.0023±0.0032. Two resonant structures are observed in the Λc+π− mass spectrum of the Λb0→Λc+pp‾π− decays, corresponding to the Σc(2455)0 and Σc⁎(2520)0 states. The ratios of branching fractions with respect to the decay Λb0→Λc+pp‾π− areB(Λb0→Σc0pp‾)×B(Σc0→Λc+π−)B(Λb0→Λc+pp‾π−)=0.089±0.015±0.006,B(Λb0→Σc⁎0pp‾)×B(Σc⁎0→Λc+π−)B(Λb0→Λc+pp‾π−)=0.119±0.020±0.014. In all of the above results, the first uncertainty is statistical and the second is systematic. The phase space is also examined for the presence of dibaryon resonances. No evidence for such resonances is found.
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