Single-inclusive production of large-pT charged particles in hadronic collisions at TeV energies and perturbative QCD predictions

The single inclusive spectrum of charged particles with transverse momenta pT = 3 – 150 GeV/c measured at midrapidity by the CDF experiment in proton-antiproton $\left( {p - \bar{p}} \right)$ collisions at $\sqrt {s} = 1.96{\text{ TeV}}$ is compared to next-to-leading order (NLO) perturbative QCD calculations using the most recent parametrizations of the parton distributions and parton-to-hadron fragmentation functions. Above pT ≈ 20 GeV/c, there is a very sizeable disagreement of the Tevatron data compared to the NLO predictions and to xT-scaling expectations, suggesting a problem in the experimental data. We also present the predictions for the pT-differential charged hadron spectra and the associated theoretical uncertainties for proton-proton (p-p) collisions at LHC energies $\left( {\sqrt {s} = 0.9 - 14{\text{ TeV}}} \right)$. Two procedures to estimate the charged hadron spectra at LHC heavy-ion collision energies $\left(\sqrt {s} = 2.76 \right)$, 5.5 TeV) from p-p measurements are suggested

Determination of fs/fd for 7 TeV pp Collisions and Measurement of the B0→D−K+ Branching Fraction

The relative abundance of the three decay modes B 0 → D − K + , B 0 → D − π + , and B 0 s → D − s π + produced in 7 TeV p p collisions at the LHC is determined from data corresponding to an integrated luminosity of 35     pb − 1 . The branching fraction of B 0 → D − K + is found to be B ( B 0 → D − K + ) = ( 2.01 ± 0.18 stat ± 0.14 syst ) × 10 − 4 . The ratio of fragmentation fractions f s / f d is determined through the relative abundance of B 0 s → D − s π + to B 0 → D − K + and B 0 → D − π + , leading to f s / f d = 0.253 ± 0.017 ± 0.017 ± 0.020 , where the uncertainties are statistical, systematic, and theoretical, respectively

Search for CP violation in D+→K−K+π+ decays

A model-independent search for direct C P violation in the Cabibbo-suppressed decay D + → K − K + π + in a sample of approximately 370 000 decays is carried out. The data were collected by the LHCb experiment in 2010 and correspond to an integrated luminosity of 35     pb − 1 . The normalized Dalitz plot distributions for D + and D − are compared using four different binning schemes that are sensitive to different manifestations of C P violation. No evidence for C P asymmetry is found

Measurement of V 0 production ratios in pp collisions at s √ = 0.9 and 7 TeV

The Λ¯/Λ and Λ¯/K0S production ratios are measured by the LHCb detector from 0.3 nb−1 of pp collisions delivered by the LHC at s√=0.9 TeV and 1.8 nb−1 at s√=7 TeV. Both ratios are presented as a function of transverse momentum, p T, and rapidity, y, in the ranges 0.15 < p T < 2.50 GeV/c and 2.0 < y < 4.5. Results at the two energies are in good agreement as a function of rapidity loss, ∆y = y beam − y, and are consistent with previous measurements. The ratio Λ¯/Λ , measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio Λ¯/K0S , measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected

Measurement of V 0 production ratios in pp collisions at s √ = 0.9 and 7 TeV

The Λ¯/Λ and Λ¯/K0S production ratios are measured by the LHCb detector from 0.3 nb−1 of pp collisions delivered by the LHC at s√=0.9 TeV and 1.8 nb−1 at s√=7 TeV. Both ratios are presented as a function of transverse momentum, p T, and rapidity, y, in the ranges 0.15 < p T < 2.50 GeV/c and 2.0 < y < 4.5. Results at the two energies are in good agreement as a function of rapidity loss, ∆y = y beam − y, and are consistent with previous measurements. The ratio Λ¯/Λ , measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio Λ¯/K0S , measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected

Search for CP violation in D+→K−K+π+ decays

A model-independent search for direct C P violation in the Cabibbo-suppressed decay D + → K − K + π + in a sample of approximately 370 000 decays is carried out. The data were collected by the LHCb experiment in 2010 and correspond to an integrated luminosity of 35     pb − 1 . The normalized Dalitz plot distributions for D + and D − are compared using four different binning schemes that are sensitive to different manifestations of C P violation. No evidence for C P asymmetry is found