The LPM effect in sequential bremsstrahlung: dimensional regularization

Journal Article · 19 October 2016 · Journal of High Energy Physics (Online)

DOI: https://doi.org/10.1007/JHEP10(2016)100 · OSTI ID:1425938

Arnold, Peter ^[1]; Chang, Han-Chih ^[1]; Iqbal, Shahin ^[2]

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1. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Physics
2. Quaid-i-Azam Univ., Islamabad (Pakistan). National Centre for Physics

The splitting processes of bremsstrahlung and pair production in a medium are coherent over large distances in the very high energy limit, which leads to a suppression known as the Landau-Pomeranchuk-Migdal (LPM) effect. Of recent interest is the case when the coherence lengths of two consecutive splitting processes overlap (which is important for understanding corrections to standard treatments of the LPM effect in QCD). In previous papers, we have developed methods for computing such corrections without making soft-gluon approximations. However, our methods require consistent treatment of canceling ultraviolet (UV) divergences associated with coincident emission times, even for processes with tree-level amplitudes. In this paper, we show how to use dimensional regularization to properly handle the UV contributions. We also present a simple diagnostic test that any consistent UV regularization method for this problem needs to pass.

• Research Organization: Univ. of Virginia, Charlottesville, VA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: SC0007984
• OSTI ID: 1425938
• Journal Information: Journal of High Energy Physics (Online), Vol. 2016, Issue 10; ISSN 1029-8479
• Publisher: Springer BerlinCopyright Statement
• Country of Publication: United States
• Language: English