Total cross section of two-photon production of hadrons (original) (raw)
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Inclusive charged hadron production in two-photon collisions at LEP
Physics Letters B, 2003
Inclusive charged hadron production, e + e − → e + e − h ± X, is studied using 414 pb −1 of data collected at LEP with the L3 detector at centre-of-mass energies between 189 and 202 GeV. Single particle inclusive differential cross sections are measured as a function of the particle transverse momentum, p t , and pseudo-rapidity, η. For p t ≤ 1.5 GeV, the data are well described by an exponential, typical of soft hadronic processes. For higher p t , the onset of perturbative QCD processes is observed. The π ± production cross section for p t > 5 GeV is much higher than the NLO QCD predictions.
Hadronic cross-sections in two photon processes at a future linear collider
Journal of High Energy Physics, 2003
In this note we address the issue of measurability of the hadronic crosssections at a future photon collider as well as for the two-photon processes at a future high energy linear e + e − collider. We extend, to higher energy, our previous estimates of the accuracy with which the γγ cross-section needs to be measured, in order to distinguish between different theoretical models of energy dependence of the total cross-sections. We show that the necessary precision to discriminate among these models is indeed possible at future linear colliders in the Photon Collider option. Further we note that even in the e + e − option a measurement of the hadron production cross-section via γγ processes, with an accuracy necessary to allow discrimination between different theoretical models, should be possible. We also comment briefly on the implications of these predictions for hadronic backgrounds at the future TeV energy e + e − collider CLIC.
2012
The differential cross section for production of charged hadrons with high transverse momenta in scattering of 160 GeV/c muons off nucleons at low photon virtualities has been measured at the COMPASS experiment at CERN. The results, which cover transverse momenta from 1.1 GeV/c to 3.6 GeV/c, are compared to a perturbative Quantum Chromodynamics (pQCD) calculation, in order to evaluate the applicability of pQCD to this process in the kinematic domain of the experiment. The shape of the calculated differential cross section as a function of transverse momentum is found to be in good agreement with the experimental data, but the absolute scale is underestimated by next-toleading order (NLO) pQCD. The inclusion of all-order resummation of large logarithmic threshold corrections reduces the discrepancy from a factor of three to four to a factor of two. The dependence of the cross section on the pseudo-rapidity and on virtual photon energy fraction is investigated. Finally the dependence on the charge of the hadrons is discussed.
Measurement of the cross-section for the process gamma*gamma*-- >hadrons at LEP
Clinical and Experimental Hypertension, 1999
Measurements of the two-photon interaction e+e--->e+e-+hadrons at sqrt(s)~=91 GeV and sqrt(s)~=183 GeV are presented. The double-tag events, collected with the L3 detector, correspond to integrated luminosities of 140 pb-1 at 91 GeV and 52 pb-1 at 183 GeV. The cross-section of γ*γ* collisions has been measured at =3.5 GeV2 and =14 GeV2. The data agree well with predictions based on perturbative QCD, while the Quark Parton Model alone is insufficient to describe the data.
Nuclear Physics B, 1996
The next-to-leading-order (NLO) cross section for the production of heavy quarks at large transverse momenta (p±) in 3,3/collisions is calculated with perturbative fragmentation functions (PFFs). This approach allows for a resummation of terms cx as ln(p~/m 2) which arise in NLO from colfinear emission of gluons by heavy quarks at large p± or from almost collinear branching of photons or gluons into heavy-quark pairs. We present single-inclusive distributions in p± and rapidity including direct and resolved photons for yy production of heavy quarks at e+e -colliders and at high-energy yy colliders. The results are compared with the fixed-order calculation for m finite including QCD radiative corrections. The two approaches differ in the definitions and relative contributions of the direct and resolved terms, but essentially agree in their sum. The resummation of the as ln(p2/m e) terms in the PFF approach leads to a softer p± distribution and to a reduced sensitivity to the choice of the renormalization and factorization scales.
Physical Review D, 2005
We present a new measurement of the inclusive and differential production cross sections of J/ψ mesons and b hadrons in proton-antiproton collisions at √(s)=1960 GeV. The data correspond to an integrated luminosity of 39.7 pb-1 collected by the CDF run II detector. We find the integrated cross section for inclusive J/ψ production for all transverse momenta from 0 to 20 GeV/c in the rapidity range |y|<0.6 to be 4.08±0.02(stat)+0.36-0.33(syst) μb. We separate the fraction of J/ψ events from the decay of the long-lived b hadrons using the lifetime distribution in all events with pT(J/ψ)>1.25 GeV/c. We find the total cross section for b hadrons, including both hadrons and antihadrons, decaying to J/ψ with transverse momenta greater than 1.25 GeV/c in the rapidity range |y(J/ψ)|<0.6 is 0.330±0.005(stat)+0.036-0.033(syst) μb. Using a Monte Carlo simulation of the decay kinematics of b hadrons to all final states containing a J/ψ, we extract the first measurement of the total single b-hadron cross section down to zero transverse momentum at √(s)=1960 GeV. We find the total single b-hadron cross section integrated over all transverse momenta for b hadrons in the rapidity range |y|<0.6 to be 17.6±0.4(stat)+2.5-2.3(syst) μb.