共查询到20条相似文献,搜索用时 125 毫秒
1.
Ukegawa F Valls J Vejcik S Velev G Vidal R Vilar R Vologouev I Vucinic D Wagner RG Wagner RL Wahl J Wallace NB Walsh AM Wang C Wang CH Wang MJ Watanabe T Watts T Webb R Wenzel H Wester WC Wicklund AB Wicklund E Williams HH Wilson P Winer BL 《Physical review letters》2000,84(2):232-237
We report a measurement of the fraction of b quarks produced diffractively in &pmacr;p collisions at sqrt[s] = 1.8 TeV. Diffraction is identified by the absence of particles in a forward pseudorapidity region. From events with an electron of transverse momentum 9.5
相似文献
2.
Acosta D Affolder T Akimoto H Albrow MG Ambrose D Amidei D Anikeev K Antos J Apollinari G Arisawa T Artikov A Asakawa T Ashmanskas W Azfar F Azzi-Bacchetta P Bacchetta N Bachacou H Badgett W Bailey S de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Barone M Bauer G Bedeschi F Behari S Belforte S Bell WH Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berryhill J Bhatti A Binkley M Bisello D Bishai M Blair RE Blocker C Bloom K Blumenfeld B Blusk SR Bocci A Bodek A 《Physical review letters》2004,93(14):141601
We report results from a study of events with a double-Pomeron exchange topology produced in p p collisions at sqrt[s]=1800 GeV. The events are characterized by a leading antiproton and a large rapidity gap on the outgoing proton side. We find that the differential production cross section agrees in shape with predictions based on Regge theory and factorization, and that the ratio of double-Pomeron exchange to single diffractive production rates is relatively unsuppressed as compared to the O(10) suppression factor previously measured in single diffractive production. 相似文献
3.
Parity-odd asymmetries in the decay angular distribution of a W boson produced with a hard jet in pp[over ] collisions arise only from QCD rescattering effects. If observed, these asymmetries will provide a first demonstration that perturbative QCD calculation is valid for the absorptive part of scattering amplitudes. We propose a simple observable to measure these asymmetries and perform realistic Monte Carlo simulations at energies reached at the Fermilab Tevatron. It is shown that the Tevatron run II should provide sufficient statistics to test the prediction. 相似文献
4.
Feng Yuan 《Physics letters. [Part B]》2001,510(1-4):155-160
We calculate the heavy quarkonium production in double pomeron exchange processes in perturbative QCD by using two-gluon exchange model. For the P-wave χJ productions, we find χ1 and χ2 production amplitudes which vanish in the forward scattering limit. We also calculate direct J/ψ()+γ production in the same approach, and these direct contributions are much smaller than the feeddown contributions from the P-wave states. 相似文献
5.
Central pseudorapidity gaps in events with a leading antiproton at the fermilab tevatron pp collider
Acosta D Affolder T Akimoto H Albrow MG Ambrose D Amidei D Anikeev K Antos J Apollinari G Arisawa T Artikov A Asakawa T Ashmanskas W Azfar F Azzi-Bacchetta P Bacchetta N Bachacou H Badgett W Bailey S De Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Barone M Bauer G Bedeschi F Behari S Belforte S Bell WH Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berryhill J Bhatti A Binkley M Bisello D Bishai M Blair RE Blocker C Bloom K Blumenfeld B Blusk SR Bocci A Bodek A 《Physical review letters》2003,91(1):011802
We report a measurement of the fraction of events with a large pseudorapidity gap deltaeta within the pseudorapidity region available to the proton dissociation products X in p+p-->p+X. For a final state p of fractional momentum loss xi(p) and 4-momentum transfer squared t(p) within 0.063 is found to be 0.246+/-0.001 (stat)+/-0.042 (syst) [0.184+/-0.001 (stat)+/-0.043 (syst)]. Our results are compared with gap fractions measured in minimum bias pp collisions and with theoretical expectations. 相似文献
6.
L. Clavelli 《Nuclear Physics B》1979,154(1):47-61
By an indirect method we calculate the missing mass discontiniuty of the dual two-loop graph in the double-pomeron region. We confirm the central region scaling and determine the P⊥ dependence. 相似文献
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8.
M. Della Negra D. Drijard H.G. Fischer G. Fontaine H. Frehse P. Frenkiel C. Chesquiere R. Gokieli P. Hanke W. Hofmann W. Isenbeck E.E. Kluge V. Korbel D. Linglin A. Minten A. Norton A. Putzer R. Sosnowski D. Wegener 《Physics letters. [Part B]》1976,65(4):394-396
The reaction pp→ppπ+π? at √s=31GeV was studied at the Split Field Magnet Facility of the CERN-ISR. Selecting events with two leading protons of x>0.9 and a rapidity gap Δy>2 between the protons and both pions a sample of 720 events is obtained representing a cross section of 25±10μb. The mass distribution of the dipion system, x and pT distributions for the protons are presented and analyzed for the presence of double pomeron exchange. 相似文献
9.
Zeitschrift für Physik C Particles and Fields - Rapidity and transverse momentum distributions of heavy quarks produced by double exchange of Donnachie-Landshoff pomeron are presented and... 相似文献
10.
The pionization region of the inclusive single-particle spectrum is accounted for by double pomeron exchange in the absorptive part of a six-point amplitude. In this paper a multiperipheral model for the six-point amplitude with double pomeron exchange is used for continuation by crossing and analyticity to the physical region of the exclusive two particle → four particle production process. The cross section for π? p → π?(π+π?)p in the double-Regge region is then calculated and compared with the experimental analysis of Lipes, Zweig and Robertson which sets an upper bound to the strength of the double pomeron exchange coupling. This upper bound, coupled with the model for continuation to the inclusive cross section, is shown to give too small a magnitude for the double pomeron exchange in the pionization region. Further avenues for investigation are discussed. 相似文献
11.
《The European Physical Journal C - Particles and Fields》2007,52(4):813-832
The production of dijets in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an
integrated luminosity of 61 pb-1. The dijet cross section has been measured for virtualities of the exchanged virtual photon, 5 < Q2 < 100 GeV2, and γ*p centre-of-mass energies, 100 < W < 250 GeV. The jets, identified using the inclusive kT algorithm in the γ*p frame, were required to have a transverse energy E*
T,jet > 4 GeV and the jet with the highest transverse energy was required to have E*
T,jet > 5 GeV. All jets were required to be in the pseudorapidity range -3.5<η*
jet<0. The differential cross sections are compared to leading-order predictions and next-to-leading-order QCD calculations based
on recent diffractive parton densities extracted from inclusive diffractive deep inelastic scattering data. 相似文献
12.
Dijet cross sections in neutral current deep inelastic ep scattering have been measured in the range with the ZEUS detector at HERA using an integrated luminosity of 38.4 pb. The cross sections, measured in the Breit frame using the jet algorithm, are compared with next-to-leading-order perturbative QCD calculations using proton parton distribution functions.
The uncertainties of the QCD calculations have been studied. The predictions are in reasonable agreement with the measured
cross sections over the entire kinematic range.
Received: 11 September 2001 / Published online: 20 December 2001 相似文献
13.
M. A. Braun 《Zeitschrift fur Physik C Particles and Fields》1992,56(4):643-652
Particle production at very high energies inhh, hA andAB collisions is studied in the framework of the pomeron model with a strong self-interaction proposed by Cardy. It is shown that the interaction between pomerons substancially damps the production rate one nuclei, the multiplicities forhA collisions becomingA-independent. 相似文献
14.
First measurements of inclusive W and Z cross sections from run II of the fermilab tevatron collider
Acosta D Affolder T Akimoto T Albrow MG Ambrose D Amerio S Amidei D Anastassov A Anikeev K Annovi A Antos J Aoki M Apollinari G Arisawa T Arguin JF Artikov A Ashmanskas W Attal A Azfar F Azzi-Bacchetta P Bacchetta N Bachacou H Badgett W Barbaro-Galtieri A Barker GJ Barnes VE Barnett BA Baroiant S Barone M Bauer G Bedeschi F Behari S Belforte S Bellettini G Bellinger J Benjamin D Beretvas A Bhatti A Binkley M Bisello D Bishai M Blair RE Blocker C Bloom K Blumenfeld B Bocci A Bodek A Bolla G 《Physical review letters》2005,94(9):091803
We report the first measurements of inclusive W and Z cross sections times leptonic branching ratios for pp collisions at square root[s]=1.96 TeV, based on their decays to electrons and muons. The data correspond to an integrated luminosity of 72 pb(-1) recorded with the CDF detector at the Fermilab Tevatron. We test e-mu universality in W decays, and we measure the ratio of leptonic W and Z rates from which the leptonic branching fraction B(W-->lnu) can be extracted as well as an indirect value for the total width of the W and the Cabibbo-Kobayashi-Maskawa matrix element, |V(cs)|. 相似文献
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16.
The transverse momentum Q(T) distribution is computed for inclusive Higgs boson production at sqrt[S]=1.96 TeV. We include all-orders resummation of large logarithms associated with emission of soft gluons at small Q(T). We provide results for Higgs boson and Z* masses from M(Z) to 200 GeV. The relatively hard transverse momentum distribution for Higgs boson production suggests possibilities for improvement of the signal to background ratio. 相似文献
17.
We study the double parton interaction process in collisions between highly virtual pairs in the BFKL regime. Explicit expressions for the double parton distributions are obtained both in the case of direct
coupling of the BFKL pomerons to the pair and in the case of triple pomeron interaction.
Received: 9 May 2000 / Revised version: 14 August 2000 / Published online: 23 January 2001 相似文献
18.
Ratios of azimuthal angle correlations between two jets produced at large rapidity separation are studied in the N = 4 maximally supersymmetric Yang-Mills (MSYM) theory. It is shown that these observables, which directly prove the SL(2,C) symmetry present in gauge theories in the Regge limit, exhibit an excellent perturbative convergence. They are compared to those calculated in QCD for different renormalization schemes concluding that the momentum-substraction scheme with the Brodsky-Lepage-Mackenzie scale-fixing procedure captures the bulk of the MSYM results. 相似文献
19.
A.C. Irving 《Nuclear Physics B》1977,121(1):176-188
A model for predicting diffractive production of meson resonances is presented. From a study of the s and t dependence of the available cross section and density matrix data, we deduce that the assumption of f, f′ dominance of the pomeron is violated. Relative to elastic scattering, where f, f′ dominance works well, the pomeron component in these inelastic processes appears to be about one half as strong in amplitude. 相似文献
20.
Abe F Akimoto H Akopian A Albrow MG Amendolia SR Amidei D Antos J Anway-Wiese C Aota S Apollinari G Arisawa T Asakawa T Ashmanskas W Atac M Azfar F Azzi-Bacchetta P Bacchetta N Badgett W Bagdasarov S Bailey MW Bao J de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Barzi E Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Bensinger J Benton D Beretvas A Berge JP Berryhill J Bertolucci S Bevensee B Bhatti A Biery K Binkley M Bisello D Blair RE 《Physical review letters》1996,77(27):5336-5341