scholarly journals High-energy operator product expansion at sub-eikonal level

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Giovanni Antonio Chirilli

Abstract The high energy Operator Product Expansion for the product of two electromagnetic currents is extended to the sub-eikonal level in a rigorous way. I calculate the impact factors for polarized and unpolarized structure functions, define new distribution functions, and derive the evolution equations for unpolarized and polarized structure functions in the flavor singlet and non-singlet case.

Author(s):  
GIOVANNI ANTONIO CHIRILLI

Using the high-energy Operator Product Expansion of the T-product of two electromagnetic currents, we calculate the Photon Impact Factor for Deep Inelastic Scattering at small value of the Bjorken variable x B at the next-to-leading order (NLO) accuracy in αs. We provide for the first time an analytic expression in coordinate space and in Mellin space of the NLO impact factor for the forward unpolarized structure functions.


2012 ◽  
Vol 20 ◽  
pp. 200-207 ◽  
Author(s):  
GIOVANNI ANTONIO CHIRILLI

The high-energy QCD factorization for Deep Inelastic Scattering and for proton-nucleus collisions using Wilson line formalism and factorization in rapidity is discussed. We show that in DIS the factorization in rapidity reduces to the k T -factorization when the 2-gluon approximation is applied, provided that the composite Wilson line operator is used in the high-energy Operator Product Expansion. We then show that the inclusive forward cross-section in proton-nucleus collisions factorizes in parton distribution functions, fragmentation functions and dipole gluon distribution function at one-loop level.


2015 ◽  
Vol 37 ◽  
pp. 1560055
Author(s):  
Giovanni Antonio Chirilli

The analytic NLO cross section of the γ*γ* scattering process at high-energy is calculated. The result is obtained factorizing the scattering amplitude in rapidity space using the high-energy Operator Product Expansion in terms of composite Wilson line operators. The next-to-leading logarithmic resummation is included employing the solution of the NLO BFKL equation which obtained from the linearization of the evolution in rapidity space of the composite Wilson line operators.


2006 ◽  
Vol 24 (4) ◽  
pp. 467-468
Author(s):  
Dieter H.H. Hoffmann

The primary goal of Laser and Particle Beams as part of the Cambridge University Press is the dissemination of knowledge in our research field. How effective we are in this respect is not easy to determine. But the impact factor published annually in June by Thomson ISI® 2005 Journal Citation Reports (JCR), gives at least an indication and a method to compare other journals in the field. In this respect, Laser and Particle Beams is a journal with a very high ranking in the field of applied physics, but it also compares very well to journals in other field of physics. The impact factor of a journal gives an account of how often an average paper in the journal is referred to, in a two year time span after publication. The current impact factor of 2.59 is based on an evaluation conducted in 2005 of Laser and Particle Beams publications of 2003 and 2004. During the evaluation period (2005), Laser and Particle Beams publications were cited about 1000 times. The topics that attracted most attention were Fast Ignition (Deutsch, 2004; Mulser & Schneider, 2004a; Hora, 2004; Mulser & Bauer, 2004b), Inertial Fusion Targets (Borisenko et al., 2003), and Ion and Electron Acceleration in laser plasma and Ultrashort Pulses (Shorokhov & Pukhov, 2004; Osman et al., 2004; Malka & Fritzler, 2004; Limpouch et al., 2004; Pegoraro et al., 2004). However, the editorial boards of Laser and Particle Beams strongly encourage authors to submit their results in High Energy Density Physics, the emerging field of Warm Dense Matter, Pulsed Power and Accelerator Physics and Technology.


2002 ◽  
Vol 17 (23) ◽  
pp. 3220-3238
Author(s):  
UTA STÖSSLEIN

Recent progress in the field of spin physics of high energy particle interactions is reviewed with particular emphasis on the spin structure functions as measured in polarized deep inelastic lepton-nucleon scattering (DIS). New measurements are presented to obtain more direct information on the composition of the nucleon angular momentum, with results from semi-inclusive DIS accessing flavour-separated parton distribution functions (PDF) and with first data from hard exclusive reactions which may be interpreted in terms of recently developed generalizations of parton distribution functions (GPD). Finally, experimental prospects are outlined which will lead to a further development of the virtues of QCD phenomenology of the spin structure of the nucleon.


2010 ◽  
Vol 25 (05) ◽  
pp. 909-949 ◽  
Author(s):  
T. ADAMS ◽  
P. BATRA ◽  
L. BUGEL ◽  
L. CAMILLERI ◽  
J. M. CONRAD ◽  
...  

We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDF's). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parametrized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of "Beyond the Standard Model" physics.


2021 ◽  
Vol 81 (9) ◽  
Author(s):  
G. R. Boroun ◽  
B. Rezaei

AbstractWe present nonlinear corrections (NLCs) to the distribution functions at low values of x and $$Q^{2}$$ Q 2 using the parametrization $$F_{2}(x,Q^{2})$$ F 2 ( x , Q 2 ) and $$F_{L}(x,Q^{2})$$ F L ( x , Q 2 ) . We use a direct method to extract nonlinear corrections to the ratio of structure functions and the reduced cross section in the next-to-next-to-leading order (NNLO) approximation with respect to the parametrization method (PM). Comparisons between the nonlinear results with the bounds in the color dipole model (CDM) and HERA data indicate the consistency of the nonlinear behavior of the gluon distribution function at low x and low $$Q^{2}$$ Q 2 . The nonlinear longitudinal structure functions are comparable with the H1 Collaboration data in a wide range of $$Q^{2}$$ Q 2 values. Consequently, the nonlinear corrections at NNLO approximation to the reduced cross sections at low and moderate $$Q^{2}$$ Q 2 values show good agreement with the HERA combined data. These results at low x and low $$Q^{2}$$ Q 2 can be applied to the LHeC region for analyses of ultra-high-energy processes.


2017 ◽  
Vol 118 (24) ◽  
Author(s):  
A. J. Chambers ◽  
R. Horsley ◽  
Y. Nakamura ◽  
H. Perlt ◽  
P. E. L. Rakow ◽  
...  

1998 ◽  
Vol 57 (7) ◽  
pp. 4069-4079 ◽  
Author(s):  
Vittorio Del Duca ◽  
Carl R. Schmidt

1997 ◽  
Vol 50 (1) ◽  
pp. 139
Author(s):  
Takayuki Shigetani ◽  
Katsuhiko Suzuki ◽  
Hiroshi Toki

We study the structure functions of hadrons with the low energy effective theory of QCD. We try to clarify a link between the low energy effective theory, where non-perturbative dynamics is essential, and the high energy deep inelastic scattering experiment. We calculate the leading twist matrix elements of the structure function at the low energy model scale within the effective theory. Calculated structure functions are taken to the high momentum scale with the help of the perturbative QCD, and compared with the experimental data. Through a comparison of the model calculations with the experiment, we discuss how the non-perturbative dynamics of the effective theory is reflected in the deep inelastic phenomena. We first evaluate the structure functions of the pseudoscalar mesons using the NJL model. The resulting structure functions show reasonable agreement with experiments. We then study the quark distribution functions of the nucleon using a covariant quark–diquark model. We calculate three leading twist distribution functions, the spin-independent f1(x), the longitudinal spin distribution g1(x), and the chiral-odd transversity spin distribution h1(x). The results for f1(x) and g1(x) turn out to be consistent with available experiments because of the strong spin-0 diquark correlation.


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