共查询到20条相似文献,搜索用时 15 毫秒
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In this work we estimate the heavy quark production in proton-proton and proton-nucleus collisions at LHC energies using the color dipole formalism and the solution of the running coupling Balitsky-Kovchegov equation. Nuclear effects are considered in the computation of the total cross sections and rapidity distributions for scattering on protons and nuclei. 相似文献
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We obtain a relation between the longitudinal structure function F
L(x, Q
2), F
2(x, Q
2) and G(x, Q
2) at small x, using the formalism recently reported by one of the authors [2]. We also obtain a relation between F
L(x, Q
2), F
2(x, Q
2) and its slope (dF
2(x, Q
2))/(dlnQ
2). This provides us with the determination of the longitudinal structure function F
L(x, Q
2) from F
2(x, Q
2) data and hence extract the gluon distribution G(x, Q
2). 相似文献
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B. Badełek J. Kwieciński A. Staśto 《Zeitschrift fur Physik C Particles and Fields》1997,74(2):297-305
A model for the longitudinal structure function FL at low x and low Q2 is presented, which includes the kinematical constraint FL ~ Q4 as Q2 → 0. It is based on the photon-gluon fusion mechanism suitably extrapolated to the region of low Q2. The contribution of quarks having limited transverse momentum is treated phenomenologically assuming that it is described by the soft pomeron exchange mechanism. The ratio R = FL/(F2 ? FL), with the F2 appropriately extrapolated to the region of low Q2, is also discussed. 相似文献
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M. G. Ryskin Yu. M. Shabelski A. G. Shuvaev 《Zeitschrift fur Physik C Particles and Fields》1997,73(1):111-117
We consider the light quark electroproduction cross section. 相似文献
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L. Favart M. Gruwé P. Marage Z. Zhang 《Zeitschrift fur Physik C Particles and Fields》1996,72(3):425-428
It is shown that a significant measurement of the longitudinal structure functionF L (x, Q 2) can be performed at HERA, forQ 2=2 GeV2 andQ 2=5 GeV2 and forx around 10?4, using radiative events with hard photon emission collinear to the incident lepton beam, under the present running conditions and with an integrated luminosity of 10 pb?1. The influence of experimental conditions is discussed. 相似文献
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N.G. Antoniou C. Chiou-Lahanas S.D.P. Vlassopulos E. Zevgolatakos 《Physics letters. [Part B]》1980,93(4):472-476
A particular j-plane singularity, leading to long-range effects in hadron scattering, is attributed to hard constituent quark interactions. A definite prediction for the nucleon structure function, including scaling violations consistent with QCD. is obtained, which is confronted with the available data. 相似文献
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R. Kirschner L. Mankiewicz A. Schäfer L. Szymanowski 《Zeitschrift fur Physik C Particles and Fields》1997,74(3):501-508
The small x behaviour of the structure function h 1 (x, Q 2) is studied within the leading logarithmic approximation of perturbative QCD. There are two contributions relevant at small x. The leading one behaves like (1/x)0 i.e. it is just a constant in this limit. The second contribution, suppressed by one power of x, includes the terms summed by the GLAP equation. Thus for h 1 (x, Q 2) the GLAP asymptotics and Regge asymptotics are completely different, making h 1(x, Q 2) quite an interesting quantity for the study of small x physics. 相似文献
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《Nuclear Physics B》1995,439(3):471-502
A measurement of the proton structure function F2(x, Q2) is reported for momentum transfers squared Q2 between 4.5 GeV2 and 1600 GeV2 and for Bjorken x between 1.8 × 10−14 and 0.13 using data collected by the HERA experiment H1 in 1993. It is observed that F2 increases significantly with decreasing x, confirming our previous measurement made with one tenth of the data available in this analysis. The Q2 dependence is approximately logarithmic over the full kinematic range covered. The subsample of deep inelastic events with a large pseudo-rapidity gap in the hadronic energy flow close to the proton remnant is used to measure the “diffractive” contribution to F2. 相似文献
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B. Badełek J. Kwiecinski B. Ziaja 《The European Physical Journal C - Particles and Fields》2002,26(1):45-49
Theoretical predictions for the polarized nucleon structure function g
1
(x, Q
2
) at low Q2 are obtained in the framework of the generalized vector meson dominance model. Contributions from both light and heavy vector
mesons are evaluated. In the photoproduction limit the first moment of g1 is related to the static properties of the nucleon via the Drell-Hearn-Gerasimov-Hosoda-Yamamoto sum rule. This property
is employed to fix the magnitude of the light vector meson contribution to g1, using the recent measurements in the region of baryonic resonances. The results are compared to the data on g
1
(x, Q
2
). Finally, the DHGHY moment function I(Q
2
) is calculated, and our theoretical predictions are confronted with the recent preliminary data obtained at the Jefferson
Laboratory.
Received: 9 July 2002 / Published online: 7 October 2002
RID="a"
ID="a" e-mail: badelek@fuw.edu.pl
RID="b"
ID="b" e-mail: jan.kwiecinski@ifj.edu.pl
RID="c"
ID="c" e-mail: ziaja@tsl.uu.se 相似文献
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We study the periodic cosmic transit behavior of the accelerated universe in the framework of symmetric teleparallelism. The exact solution of field equations is obtained by employing a well-known deceleration parameter (DP) called periodic varying DP, $q=m\cos {kt}-1$. The viability and physical reliability of the DP are studied by using observational constraints. The dynamics of periodicity and singularity are addressed in detail with respect to time and redshift parameter. Several energy conditions are discussed in this setting. 相似文献
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W. Vogelsang 《Zeitschrift fur Physik C Particles and Fields》1991,50(2):275-283
We present a careful analysis of the polarized photon-gluon fusion process. Discussing various regularization schemes it is demonstrated that one can safely extract a hard gluonic contribution to the proton's spin dependent structure functiong 1 P . The value of the first moment of the gluonic Wilson coefficient is shown to be in agreement with the anomaly result. Furthermore, we examine the question whether the gluonic contribution alone can account for existing experimental data forg 1 P (x,Q 2) (x≧0.01, <Q 2>?Q 0 2 =10 GeV2) and find a positive answer. 相似文献
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At lowx, an analytic solution of the DGLAP equation for gluon in the next-to-leading order (NLO) is obtained by applying the method
of characteristics. Its compatibility with double leading logarithmic approximation (DLLA) asymptotics is discussed and comparison
with the exact ones like GRV98NLO is made. The solution is then utilized to calculate the derivatives∂F
2 (x,Q
2)/∂ lnQ
2
and ∂ lnF
2(x,Q
2)/∂ ln (1/x) and compared with the recent HERA data. Our solution is found to reproduce most of the essential features of the data on
the derivatives. 相似文献
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Fatemi R Skabelin AV Burkert VD Crabb D De Vita R Kuhn SE Minehart R Adams G Anciant E Anghinolfi M Asavapibhop B Audit G Auger T Avakian H Bagdasaryan H Ball JP Barrow S Battaglieri M Beard K Bektasoglu M Bellis M Bertozzi W Bianchi N Biselli AS Boiarinov S Bonner BE Bosted PE Bouchigny S Bradford R Branford D Brooks WK Butuceanu C Calarco JR Carman DS Carnahan B Cetina C Ciciani L Clark R Cole PL Coleman A Connelly J Cords D Corvisiero P Crannell H Cummings JP De Sanctis E Degtyarenko PV 《Physical review letters》2003,91(22):222002
Double-polarization asymmetries for inclusive ep scattering were measured at Jefferson Lab using 2.6 and 4.3 GeV longitudinally polarized electrons incident on a longitudinally polarized NH3 target in the CLAS detector. The polarized structure function g(1)(x,Q2) was extracted throughout the nucleon resonance region and into the deep inelastic regime, for Q(2)=0.15-1.64 GeV2. The contributions to the first moment Gamma(1)(Q2)= integral g(1)(x,Q2) dx were determined up to Q(2)=1.2 GeV2. Using a parametrization for g(1) in the unmeasured low x regions, the complete first moment was estimated over this Q2 region. A rapid change in Gamma(1) is observed for Q2<1 GeV2, with a sign change near Q(2)=0.3 GeV2, indicating dominant contributions from the resonance region. At Q(2)=1.2 GeV2 our data are below the perturbative QCD evolved scaling value. 相似文献