The production of leading neutrons, where the neutron carries a large fraction x_L of the incoming proton's longitudinal momentum, is studied in deep-inelastic positron-proton scattering at HERA. The data were taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of 122 pb^{-1}. The semi-inclusive cross section is measured in the phase space defined by the photon virtuality 6 < Q^2 < 100 GeV^2, Bjorken scaling variable 1.5x10^{-4} < x < 3x10^{-2}, longitudinal momentum fraction 0.32 < x_L < 0.95 and neutron transverse momentum p_T < 0.2 GeV. The leading neutron structure function, F_2^{LN(3)}(Q^2,x,x_L), and the fraction of deep-inelastic scattering events containing a leading neutron are studied as a function of Q^2, x and x_L. Assuming that the pion exchange mechanism dominates leading neutron production, the data provide constraints on the shape of the pion structure function.
Differential cross section of leading neutron production.
The semi-inclusive leading neutron structure function for Q**2.
The semi-inclusive leading neutron structure function for Q**2.
The inclusive cross section for the photoproduction of neutral pions has been measured as a function of the transverse momentum, rapidity, and Feynman x of the pizero mesons at an average photon--proton centre-of-mass energy of 208 GeV and for photon virtualities below Q^2=0.01 GeV^2. The pizero measurement extends the range covered by previous charged particle measurements at HERA by two units of rapidity in the photon direction down to a value of -5.5 in the gamma p centre-of-mass frame. The pizero transverse momentum distribution is well described over the whole measured range by a power law ansatz, while an exponential fit falls below the data at transverse momentum values above 1.5 GeV/c. Good agreement with the predictions of the Monte Carlo models PYTHIA and PHOJET is found. In the context of the PYTHIA model the data are inconsistent with large intrinsic transverse momentum values in the photon.
The inclusive PI0 photoproduction cross section in bias of rapidity and PT.Bin centre corrections have been applied and the errors are the quadratic sum o f the statistics and systematics (which dominate).
The inclusive PI0 photoproduction cross section as a function of PT for therapidity range -3.5 to -1.5. Bin centres are given in addition to limits. Error s are the quadratic sum of statistics and systematics.
The inclusive PI0 photoproduction cross section as a function of XL (the Feyman X variable) for the rapidity range -3.5 to -1.5. Bin centres are given as well as limits. Errors are the quadratic sum of statistics and systematics.
None
THE BETTER FIT FOR PI- AND BARIONBAR IS THE SUM OF TWO EXPONENT: A*EXP(-B1*PT**2)+D*EXP(-B2*PT**2).FOR PI- B1=30+-4 AND B2=6.3+-.3 .FOR BARIONBAR B1=46+-18 AND B2=3.9+-.5.
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
Results are presented on inclusive production of resonant and non-resonant particle systems produced inK+p interactions at 32 GeV/c. We compareK*+(892),\(\bar \Sigma ^{ *- } \)(1385), Σ*±(1385), and ϱ0 inclusivex-spectra with the ones of non-resonantKs0π±,\(\bar \Lambda \pi ^ -\), Λπ± and π+π− pairs at the same effective mass. Resonance-particle pairsK*+π±, Σ*+π−, and\(\bar \Sigma ^{ *- } \pi ^ -\) are also studied together with non-resonant tripletsKs0π±, Λπ+π−,\(\bar \Lambda \pi ^ -\pi ^ -\). The invariantx-spectra of resonant particle pairs decrease less rapidly withx then the corresponding non-resonant pairs. Comparison with quark-recombination predictions indicates that the particles, resonances and multiparticle systems are probably created off a single valence quark or diquark instead of carrying all possible valence-quarks.
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
The inclusive production of Ξ + and Ξ − hyperons is investigated in K + p interactions at 32 GeV/ c . The production cross sections, 36.4±9 μ b for the Ξ + and 6.5±3 μ b for the Ξ − , are rising strongly with energy similarly to Λ and Λ production in K + p interactions. The Ξ + are produced preferentially in the forward direction in the c.m.s., while the Ξ − are produced dominantly backwards. The average transverse momenta 〈p T 〉 Ξ + =0.73±0.09 GeV /c and 〈 p T 〉 Ξ − =0.58±0.09 GeV/ c .
No description provided.
No description provided.
No description provided.
None
No description provided.
No description provided.
No description provided.
Forum