We present a measurement of the inline image production cross section inline image in inline image collisions at inline image using 5.4 fb-1 of integrated luminosity collected with the D0 detector. ...We consider final states with at least two jets and two leptons (ee, eI14, I14I14), and events with one jet for the eI14 final state as well. The measured cross section is inline image. This result combined with the cross section measurement in the lepton + jets final state yields inline image, which agrees with the standard model expectation. The relative precision of 8% of this measurement is comparable to the precision of the latest theoretical calculations.
We present evidence for diffractive exclusive dijet production with an invariant dijet mass greater than 100 GeV in data collected with the D0 experiment at the Fermilab Tevatron Collider. A ...discriminant based on calorimeter information is used to measure a significant number of events with little energy (typically less than 10 GeV) outside the dijet system, consistent with the diffractive exclusive dijet production topology. The probability for these events to be explained by other dijet production processes is 2x super(10-6, corresponding to a 4.7 standard deviation significance.)
An analysis of the experimental data on one-pion and two-pion production in the
p
(
α, α
′)
X
reaction studied in a semi-exclusive experiment at an energy of
E
α
= 4.2 GeV has been performed. The ...obtained results demonstrate that the inelastic
α
-particle scattering on the proton at the energy of the experiment proceeds either through excitation and decay of the Δ resonance in the projectile
α
particle, or through excitation in the target proton of the Roper resonance, which decays into a nucleon and a pion, or a nucleon and a
σ
meson—a system of two pions in the isospin
I
= 0,
S
-wave state.
The cross-section for inclusive phi meson production in pp collisions at a centre-of-mass energy of inline image has been measured with the LHCb detector at the Large Hadron Collider. The ...differential cross-section is measured as a function of the phi transverse momentum p sub(T and rapidity y in the region 0.6p) sub(T)5.0 GeV/c and 2.44y4.06. The cross-section for inclusive phi production in this kinematic range is inline image, where the first systematic uncertainty depends on the p sub(T and y region and the second is related to the overall scale. Predictions based on the Pythia 6.4 generator underestimate the cross-section.)
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A study of ... meson production at LHCb is performed on proton-proton collision data, corresponding to 3.0...of integrated ...luminosity collected at centre-of-mass energies ... = 7 and 8 ... The fraction of ... mesons originating from ... decays is measured as a function of the ... transverse momentum in the rapidity range ... The radiative transition of the ... meson to ... is observed for the first time. The ... mass is determined to be ... ...where the first uncertainty is statistical and the second is systematic.
In order to clear up the sensitivity of the nucleus--nucleus reaction cross sections \(\sigma_R\) to the nuclear matter distributions in exotic halo nuclei, we have calculated the values of ...\(\sigma_R\) for scattering of \(^6\)He, \(^{11}\)Li, and \(^{19}\)C nuclei on several nuclear targets at the energy of 0.8 GeV/nucleon. The calculations were performed in the "rigid target" approximation to the Glauber theory, different shapes of the nuclear density distributions in \(^6\)He, \(^{11}\)Li, and \(^{19}\)C being assumed.
Invariant mass distributions of B+pi- and B0pi+ combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0 fb-1 of pp collision ...data, recorded by the LHCb detector at centre-of-mass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B_1(5721)^(0,+) and B_2*(5747)^(0,+) states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 5850--6000 MeV in both B+pi- and B0pi+ combinations. The structures are consistent with the presence of four excited B mesons, labelled B_J(5840)^(0,+) and B_J(5960)^(0,+), whose masses and widths are obtained under different hypotheses for their quantum numbers.
PDF
