Abstract
We study two experimental ways to measure the heavy-quark content of the proton: using the Callan-Gross ratio R(x, Q 2) = F L /F T and/or the azimuthal cos(2φ) asymmetry in DIS. Our approach is based on the following observations. First, the ratio R(x, Q 2) = F L /F T and azimuthal cos(2φ) asymmetry in heavy-quark leptoproduction are stable, both parametrically and perturbatively, within pQCD. Second, both these quantities are sensitive to resummation of the mass logarithms of the type αsln(Q 2/m 2). We conclude that the heavy-quark densities in the nucleon can, in principle, be determined from high-Q 2 data on the Callan-Gross ratio and/or the azimuthal asymmetry. In particular, the charm content of the proton can be measured in future studies at the proposed Large Hadron-Electron (LHeC) and Electron-Ion (EIC) Colliders.
Similar content being viewed by others
References
S. J. Brodsky, P. Hoyer, C. Peterson, and N. Sakai, Phys. Lett., Ser. B 93, 451 (1980).
M. A. G. Aivazis, J. C. Collins, F. I. Olness, and W.-K. Tung, Phys. Rev., Ser. D 50, 3102 (1994); J. C. Collins, Phys. Rev., Ser. D 58, 094002 (1998).
J. Pumplin, D. R. Stump, J. Huston, et al., JHEP 0207, 012 (2002); H.-L. Lai, M. Guzzi, J. Huston, et al., Phys. Rev., Ser. D 82, 074024 (2010).
M. L. Mangano, P. Nason, and G. Ridolfi, Nucl. Phys., Ser. B 373, 295 (1992).
R. Vogt, Eur. Phys. J. ST. 155, 213 (2008).
N. Ya. Ivanov, A. Capella, and A. B. Kaidalov, Nucl. Phys., Ser. B 586, 382 (2000); N. Ya. Ivanov, Nucl. Phys., Ser. B 615, 266 (2001); N. Ya. Ivanov, P. E. Bosted, K. Griffioen, and S. E. Rock, Nucl. Phys., Ser. B 650, 271 (2003).
N. Ya. Ivanov, Nucl. Phys., Ser. B 666, 88 (2003).
L. N. Ananikyan and N. Ya. Ivanov, Phys. Rev., Ser. D 75, 014010 (2007); Nucl. Phys., Ser. B 762, 256 (2007).
N. Ya. Ivanov and B. A. Kniehl, Eur. Phys. J., Ser. C 59, 647 (2009); N. Ya. Ivanov, Nucl. Phys., Ser. B 814, 142 (2009).
L. G. Almeida, G. Sterman, and W. Vogelsang, Phys. Rev., Ser. D 78, 014008 (2008).
W.-K. Tung, S. Kretzer, and C. Schmidt, J. Phys., Ser. G 28, 983 (2002).
M. Buza, Y. Matiounine, J. Smith, et al., Nucl. Phys., Ser. B 472, 611 (1996).
Author information
Authors and Affiliations
Additional information
Talk given at the 20th International Symposium on Spin Physics “Spin 2012”, JINR, Dubna, Russia, September 17–22, 2012.
The article is published in the original.
Rights and permissions
About this article
Cite this article
Ivanov, N.Y. How to measure the charm density in the proton. Phys. Part. Nuclei 45, 19–22 (2014). https://doi.org/10.1134/S1063779614010432
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1063779614010432