Deep inelastic scattering and its diffractive component, ep→e′γ∗p→e′XNep→e′γ∗p→e′XN, have been studied at HERA with the ZEUS detector using an integrated luminosity of 4.2 pb−14.2 pb−1. The measurement covers a wide range in the γ∗pγ∗p c.m. energy W (37–245 GeV), photon virtuality Q 2 (2.2–80 GeV2) and mass MXMX (0.28–35 GeV). The diffractive cross section for MX>2 GeVMX>2 GeV rises strongly with W ; the rise is steeper with increasing Q 2. The latter observation excludes the description of diffractive deep inelastic scattering in terms of the exchange of a single pomeron. The ratio of diffractive to total cross section is constant as a function of W , in contradiction to the expectation of Regge phenomenology combined with a naive extension of the optical theorem to γ∗pγ∗p scattering. Above MXMX of 8 GeV, the ratio is flat with Q 2, indicating a leading-twist behaviour of the diffractive cross section. The data are also presented in terms of the diffractive structure function, View the MathML sourceF2D(3)(β,xP,Q2), of the proton. For fixed β , the Q 2 dependence of View the MathML sourcexPF2D(3) changes with xPxP in violation of Regge factorisation. For fixed xPxP, View the MathML sourcexPF2D(3) rises as β→0β→0, the rise accelerating with increasing Q2. These positive scaling violations suggest substantial contributions of perturbative effects in the diffractive DIS cross section.

STUDY OF DEEP INELASTIC INCLUSIVE AND DIFFRACTIVE SCATTERING WITH THE ZEUS FORWARD PLUG CALORIMETER

BASILE, MAURIZIO;CIFARELLI, LUISA;CONTIN, ANDREA;PALMONARI, FEDERICO;RINALDI, LORENZO;SARTORELLI, GABRIELLA;ZICHICHI, ANTONINO;
2005

Abstract

Deep inelastic scattering and its diffractive component, ep→e′γ∗p→e′XNep→e′γ∗p→e′XN, have been studied at HERA with the ZEUS detector using an integrated luminosity of 4.2 pb−14.2 pb−1. The measurement covers a wide range in the γ∗pγ∗p c.m. energy W (37–245 GeV), photon virtuality Q 2 (2.2–80 GeV2) and mass MXMX (0.28–35 GeV). The diffractive cross section for MX>2 GeVMX>2 GeV rises strongly with W ; the rise is steeper with increasing Q 2. The latter observation excludes the description of diffractive deep inelastic scattering in terms of the exchange of a single pomeron. The ratio of diffractive to total cross section is constant as a function of W , in contradiction to the expectation of Regge phenomenology combined with a naive extension of the optical theorem to γ∗pγ∗p scattering. Above MXMX of 8 GeV, the ratio is flat with Q 2, indicating a leading-twist behaviour of the diffractive cross section. The data are also presented in terms of the diffractive structure function, View the MathML sourceF2D(3)(β,xP,Q2), of the proton. For fixed β , the Q 2 dependence of View the MathML sourcexPF2D(3) changes with xPxP in violation of Regge factorisation. For fixed xPxP, View the MathML sourcexPF2D(3) rises as β→0β→0, the rise accelerating with increasing Q2. These positive scaling violations suggest substantial contributions of perturbative effects in the diffractive DIS cross section.
S. Chekanov; M. Derrick; D. Krakauer; J.H. Loizides 1; S. Magill; B. Musgrave; J. Repond; R. Yoshida; M.C.K. Mattingly; P. Antonioli; G. Bari; M. Basile; L. Bellagamba; D. Boscherini; A. Bruni; G. Bruni; G. Cara Romeo; L. Cifarelli; F. Cindolo; A. Contin; M. Corradi; S. De Pasquale; P. Giusti; G. Iacobucci; A. Margotti; A. Montanari; R. Nania; F. Palmonari; A. Pesci; A. Polini; L. Rinaldi; G. Sartorelli; A. Zichichi; G. Aghuzumtsyan; D. Bartsch; I. Brock; S. Goers; H. Hartmann; E. Hilger; P. Irrgang
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/26775
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