Measurement of electron capture from electron-positron pair production in relativistic heavy ion collisions

Belkacem, A.; Gould, Harvey; Feinberg, B.; Bossingham, R.; Meyerhof, W. E.

doi:10.1103/physrevlett.71.1514

Cited by 79 publications

(37 citation statements)

References 19 publications

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“…It is therefore vital to test our quantitative understanding of the features of the BFPP process in order to ensure safe operation of the LHC, uninterrupted by lengthy quenchrecovery procedures. BFPP has been measured in fixed target experiments [9][10][11] at lower energy but not, until now, in a collider. An opportunity arose during 63 Cu 29 operation of RHIC at Brookhaven National Laboratory.…”

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confidence: 99%

Observations of Beam Losses Due to Bound-Free Pair Production in a Heavy-Ion Collider

et al. 2007

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We report the first observations of beam losses due to bound-free pair production at the interaction point of a heavy-ion collider. This process is expected to be a major luminosity limit for the CERN Large Hadron Collider when it operates with 208 Pb 82 ions because the localized energy deposition by the lost ions may quench superconducting magnet coils. Measurements were performed at the BNL Relativistic Heavy Ion Collider (RHIC) during operation with 100 GeV=nucleon 63 Cu 29 ions. At RHIC, the rate, energy and magnetic field are low enough so that magnet quenching is not an issue. The hadronic showers produced when the single-electron ions struck the RHIC beam pipe were observed using an array of photodiodes. The measurement confirms the order of magnitude of the theoretical cross section previously calculated by others. DOI: 10.1103/PhysRevLett.99.144801 PACS numbers: 29.20.Dh, 25.75.ÿq When fully-stripped heavy ions of atomic numbers Z 1 , Z 2 are brought into collision at the interaction point (IP) of a collider, a number of electromagnetic interactions are induced by the intense fields generated by the coherent action of all the Z 1;2 charges in either nucleus (for a review, see Ref.[1]). Some of these ''ultraperipheral'' interactions have much higher cross sections than the hadronic nuclear interactions that are the main object of study. Among them, the bound-free pair production (BFPP), sometimes known as electron capture from pair production, occurs when the virtual photon exchanged by the ions converts into a pair, and the electron is created in an atomic shell of one of the ions:The resulting one-electron atoms have a slightly larger magnetic rigidity than the original bare nucleus.(Magnetic rigidity is defined as p= Qe B for a particle with momentum p and charge Qe that would have bending radius in a magnetic field B). Since the transverse recoil is very small, this ''secondary beam'' will emerge at a very small angle to the main beam. However, it will be bent and focused less by the guiding magnetic elements and may be lost somewhere in the collider ring.It has long been known that this process, together with electromagnetic dissociation of the nuclei, could be a major contribution to the intensity and luminosity decay of ion colliders [2,3]. It was realized more recently [4,5] that, in certain conditions, the BFPP beam will be lost in a well-defined spot, initiating hadronic showers in the vacuum envelope of the beam. The resulting localized heat deposition could induce quenches of superconducting magnets. Detailed calculations have been given elsewhere for 2:76 TeV=nucleon 208 Pb 82 operation of the LHC at CERN [5][6][7][8]. The consequent luminosity limit is expected to occur at a level close to the design performance. It is therefore vital to test our quantitative understanding of the features of the BFPP process in order to ensure safe operation of the LHC, uninterrupted by lengthy quenchrecovery procedures. BFPP has been measured in fixed target experiments [9-11] at lower energy but not,...

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Observations of Beam Losses Due to Bound-Free Pair Production in a Heavy-Ion Collider

et al. 2007

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“…In the worst scenario, there might be enough energy in this separated beam to quench the LHC magnets as it was first pointed out by Bruce et al [1] but was investigated in further detail in Refs. [2,3,4]. A first computation on the bound-free pair production cross sections were performed by Baltz, Rhoades-Brown and Weneser [5] in the mid 1990ies.…”

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confidence: 99%

Bound-free electron-positron pair production in relativistic heavy-ion collisions

Şengül¹,

Güçlü²,

Fritzsche³

2009

Phys. Rev. A

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The bound-free electron-positron pair production is considered for relativistic heavy ion collisions. In particular, cross sections are calculated for the pair production with the simultaneous capture of the electron into the 1s ground state of one of the ions and for energies that are relevant for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Colliders (LHC). In the framework of perturbation theory, we applied Monte-Carlo integration techniques to compute the lowest-order Feynman diagrams amplitudes by using Darwin wave functions for the bound states of the electrons and Sommerfeld-Maue wave functions for the continuum states of the positrons. Calculations were performed especially for the collision of Au + Au at 100 GeV/nucleon and P b + P b at 3400 GeV/nucleon.

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“…In this process, the charge of the ion decreases and it is depleted out of the beam. For this reason, calculation of the exact bound-free electron-positron pair production cross section is important for deciding the stability of the beam [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Bound-free pair production with a correction term in relativistic heavy-ion collisions

Şengül¹

2017

Turk J Phys

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Abstract:In our previous work, we calculated bound-free electron-positron pair production cross section without a correction term. In this work, bound-free electron-positron pair production with a correction term is considered to calculate the cross section for peripheral relativistic heavy ion collisions. The Dirac wave functions have been used for the leptons and first order corrections are included. It is seen that the results for the production cross sections are considerably smaller than those of the previous calculations. We applied the same method for the calculations of the antihydrogen production cross sections as well.

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Measurement of electron capture from electron-positron pair production in relativistic heavy ion collisions

Cited by 79 publications

References 19 publications

Observations of Beam Losses Due to Bound-Free Pair Production in a Heavy-Ion Collider

Observations of Beam Losses Due to Bound-Free Pair Production in a Heavy-Ion Collider

Bound-free electron-positron pair production in relativistic heavy-ion collisions

Bound-free pair production with a correction term in relativistic heavy-ion collisions

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