1
|
Chen YY, He PL, Shaisultanov R, Hatsagortsyan KZ, Keitel CH. Polarized Positron Beams via Intense Two-Color Laser Pulses. PHYSICAL REVIEW LETTERS 2019; 123:174801. [PMID: 31702272 DOI: 10.1103/physrevlett.123.174801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/12/2019] [Indexed: 06/10/2023]
Abstract
The generation of ultrarelativistic polarized positrons during the interaction of an ultrarelativistic electron beam with a counterpropagating two-color petawatt laser pulse is investigated theoretically. Our Monte Carlo simulation, based on a semiclassical model, incorporates photon emissions and pair productions, using spin-resolved quantum probabilities in the local constant field approximation, and describes the polarization of electrons and positrons for the pair production and photon emission processes, as well as the classical spin precession in between. The main reason for the polarization is shown to be the spin asymmetry of the pair production process in strong external fields, combined with the asymmetry of the two-color laser field. Employing a feasible scenario, we show that highly polarized positron beams, with a polarization degree of ζ≈60%, can be produced in a femtosecond timescale, with a small angular divergence, ∼74 mrad, and high density, ∼10^{14} cm^{-3}. The laser-driven polarized positron source raises hope for providing an alternative for high-energy physics studies.
Collapse
Affiliation(s)
- Yue-Yue Chen
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Pei-Lun He
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
- Key Laboratory for Laser Plasmas, Ministry of Education, and School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rashid Shaisultanov
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | | | - Christoph H Keitel
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| |
Collapse
|
2
|
Bandiera L, Bagli E, Guidi V, Mazzolari A, Berra A, Lietti D, Prest M, Vallazza E, De Salvador D, Tikhomirov V. Broad and intense radiation accompanying multiple volume reflection of ultrarelativistic electrons in a bent crystal. PHYSICAL REVIEW LETTERS 2013; 111:255502. [PMID: 24483748 DOI: 10.1103/physrevlett.111.255502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Indexed: 06/03/2023]
Abstract
The radiation emitted by 120 GeV/c electrons traversing a single bent crystal under multiple volume reflection orientation is investigated. Multiple volume reflection in one crystal occurs as a charged particle impacts on a bent crystal at several axial channeling angles with respect to a crystal axis. The resulting energy-loss spectrum of electrons was very intense over the full energy range up to the nominal energy of the beam. As compared to the radiation emission by an individual volume reflection, the energy-loss spectrum is more intense and peaks at an energy 3 times greater. Experimental results are compared to a theoretical approach based on the direct integration of the quasiclassical Baier and Katkov formula. In this way, it is possible to determine the mean number of photons emitted by each electron and, thus, to extract the single-photon spectrum, which is broad and intense. The soft part of the radiation spectrum is due to the contribution of coherent interaction between electrons and several reflecting planes intersecting the same crystal axis, whereas the hard part is mainly connected to coherent bremsstrahlung induced by correlated scattering of electrons by atomic strings (string of strings scattering and radiation). The radiation generation by multiple volume reflection takes place over a broad angular range of the incident beam with respect to coherent bremsstrahlung and channeling radiation in straight crystals. Therefore, this type of radiation can be exploited for applications, such as beam dump and collimation devices for future linear colliders.
Collapse
Affiliation(s)
- L Bandiera
- INFN Sezione di Ferrara, Dipartimento di Fisica, Università di Ferrara, Via Saragat 1, 44122 Ferrara, Italy
| | - E Bagli
- INFN Sezione di Ferrara, Dipartimento di Fisica, Università di Ferrara, Via Saragat 1, 44122 Ferrara, Italy
| | - V Guidi
- INFN Sezione di Ferrara, Dipartimento di Fisica, Università di Ferrara, Via Saragat 1, 44122 Ferrara, Italy
| | - A Mazzolari
- INFN Sezione di Ferrara, Dipartimento di Fisica, Università di Ferrara, Via Saragat 1, 44122 Ferrara, Italy
| | - A Berra
- Università dell'Insubria, Via Valleggio 11, 22100 Como, Italy, and INFN Sezione di Milano Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
| | - D Lietti
- Università dell'Insubria, Via Valleggio 11, 22100 Como, Italy, and INFN Sezione di Milano Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
| | - M Prest
- Università dell'Insubria, Via Valleggio 11, 22100 Como, Italy, and INFN Sezione di Milano Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
| | - E Vallazza
- INFN Sezione di Trieste, Via Valerio 2, 34127 Trieste, Italy
| | - D De Salvador
- INFN Laboratori Nazionali di Legnaro, Viale dell'Università 2, 35020 Legnaro, Italy, and Dipartimento di Fisica, Università Di Padova, Via Marzolo 8, 35131 Padova, Italy
| | - V Tikhomirov
- Research Institute for Nuclear Problems, Belarusian State University, Minsk, Belarus
| |
Collapse
|