Abstract
We point out that the equivalent-photon approximation (EPA) for processes with massive spin-1 particles in the final state would have validity in a more restricted kinematic domain than for processes where it is commonly applied, viz., those with spin-1/2 or spin-0 particles in the final state. We obtain the criterion for the validity ofEPA for the two-photon production of a pair of charged, massive, point-like spin-1 particlesV ±, each of massM and with a standard magnetic moment (κ=1). In a process in which one of the photons is real and the other virtual with four-momentumq, the condition for the validity ofEPA is |q 2|≪M 2, in addition to the usual condition |q 2|≪W 2,W being theV + V − invariant mass. In a process in which both photons are virtual (with four-momentaq andq′), our condition is |q 2||q′2|W 4 ≪ 16M 8, in addition to |q 2| ≪M 2, |q′2| ≪M 2 and |q 2| ≪W 2, |q′2| ≪W 2. Even when these extra conditions permitting the use ofEPA are not fulfilled, convenient approximate expressions may still be obtained assuming merely |q 2| ≪W 2 and |q′2| ≪W 2.
We also discuss how the extra conditions are altered when the vector bosons are incorporated in a spontaneously broken gauge theory. Examples ofW boson production in Weinberg-Salam model are considered for which the condition |q 2||q′2|W 4 ≪ 16M 8 is shown to be removed.
Similar content being viewed by others
References
Berman S M and Tsai Y S 1963Phys. Rev. Lett. 11 224
Bohr N 1913Philos. Mag. 25 10
Bohr N 1915Philos. Mag. 30 581
Brodsky S J, Kinoshita T and Terazawa H 1971Phys. Rev. D4 1532
Budnev V M 1975Phys. Rep. C15 181
Carimalo C, Kessler P and Parisi J 1979Phys. Rev. D20 1057
Cho K H, Han S K and Kim J K 1983Phys. Rev. D27 684
Fermi E 1924Z. Phys. 29 315
Godbole R M, Pati J C, Rindani S D, Jayaraman T and Rajasekaran G 1984Phys. Lett. B142 91
Jayaraman T, Rajasekaran G and Rindani S D 1982Phys. Lett. B119 215
Jayaraman T 1983 Ph.D. Thesis, University of Madras (unpublished)
Jayaraman T, Rajasekaran G and Rindani S D 1983Do the PETRA two-photon jet experiments rule out integrally charged quarks? Contributed paper, International Conf. High Energy Physics, Brighton.
Jayaraman T, Rajasekaran G and Rindani S D 1985 (to be published)
Kamal A N, Ng J N and Lee H C 1981Phys. Rev. D24 2842
Katuya M 1983Phys. Lett. B124 421
Kessler P 1970Nucl. Phys. B15 253
Kessler P 1975Acta Phys. Austriaca 41 141
Kim K J and Tsai Y S 1972Phys. Lett. B40 665
Kim K J and Tsai Y S 1973Phys. Rev. D8 3109
Lee T D and Yang C N 1962Phys. Rev. 128 885
Mikaelian K O, Samuel M A and Sahdev D 1979Phys. Rev. Lett. 43 746
Renard F M 1979Z. Phys. C2 17
Salam A 1968 inElementary particle theory: Relativistic groups and analyticity (Nobel Symposium No. 8) (ed.) N. Svartholm (Stockholm: Almqvist and Wiksell)
Terazawa H 1973Rev. Mod. Phys. 45 615
Vainshtein A I and Khriplovich I B 1971Sov. J. Nucl. Phys. 13 114
Weinberg S 1967Phys. Rev. Lett. 19 1264
Weizsäcker C F von 1934Z. Phys. 88 612
Williams E J 1933Proc. R. Soc. (London) A139 163
Williams E J 1934Phys. Rev. 45 729
Williams E J 1935Mat. Fys. Medd. 13 4
Williamson W and Salzmann G 1963Phys. Rev. Lett. 11 483
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Jayaraman, T., Rajasekaran, G. & Rindani, S.D. Validity of the equivalent-photon approximation for the production of massive spin-1 particles. Pramana - J. Phys. 26, 21–41 (1986). https://doi.org/10.1007/BF02847564
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02847564
Keywords
- Equivalent-photon approximation
- massive spin-1 particles
- gauge theories
- electron-positron annihilation
- W+W− production