High precision measurement of the proton charge radius: The PRad experiment

Meziane, Mehdi; PRad Collaboration
November 2013
AIP Conference Proceedings;Nov2013, Vol. 1563 Issue 1, p183
Academic Journal
The recent high precision measurements of the proton charge radius performed at PSI from muonic hydrogen Lamb shift puzzled the hadronic physics community. A value of 0.8418 ± 0.0007 fm was extracted which is 7σ smaller than the previous determinations obtained from electron-proton scattering experiments and based on precision spectroscopy of electronic hydrogen. An additional extraction of the proton charge radius from electron scattering at Mainz is also in good agreement with these "electronic" determinations. An independent measurement of the proton charge radius from unpolarized elastic ep scattering using a magnetic spectrometer free method was proposed and fully approved at Jefferson Laboratory in June 2012. This novel technique uses the high precision calorimeter HyCal and a windowless hydrogen gas target which makes possible the extraction of the charge radius at very forward angles and thus very low momentum transfer Q2 up to 10-4 (GeV/c)2 with an unprecedented sub-percent precision for this type of experiment. In this paper, after a review of the recent progress on the proton charge radius extraction and the new high precision experiment PRad will be presented.


Related Articles

  • NEW DEVELOPMENTS IN PHOKHARA MONTE CARLO GENERATOR. Czyż, Henryk; Grzelińska, Agnieszka; Wapienik, Agnieszka // Acta Physica Polonica B;2007, Vol. 38 Issue 11, p3491 

    The present status of the physics program which led to the development of the Monte Carlo event generator PHOKHARA is described. The possibility of using the radiative return method in various aspects of hadronic physics, from the measurement of the hadronic cross section to detailed...

  • Charm Form Factors at the B-Factories. Oyanguren, Arantza // AIP Conference Proceedings;12/17/2009, Vol. 1182 Issue 1, p386 

    In this talk recent results on charm form factors describing the hadronic contribution in semileptonic decays at the B-factories Belle and BaBar are reviewed.

  • Hadronic light-by-light scattering in the muon g - 2: impact of proposed measurements of the Ï€0 → γγ decay width and the γ*γ → Ï€0 transition form factor with the KLOE-2 experiment. Nyffeler, Andreas // EPJ Web of Conferences;2012, Issue 37, p05002-p.1 

    We discuss, how planned measurements at KLOE-2 of the π0 → γ γ decay width and the γ*γ → π0 transition form factor can improve estimates for the numerically dominant pion-exchange contribution to hadronic light-by-light scattering in the muon g - 2 and what are...

  • Measurement of Muon Capture on the Proton. Clayton, Steven M. // AIP Conference Proceedings;2006, Vol. 870 Issue 1, p478 

    The goal of the μCap experiment is a 1% precision measurement of the muon capture rate on the free proton, which will determine the weak pseudoscalar form factor gP to 7%. At the end of 2004, the μCap detector was completed and commissioned and first physics data were taken. The analysis...

  • Elastic form factors and charge densities of medium and heavy nuclei and the proton occupancies of shell states. Gulkarov, Ilia S.; Nigam, Bishan P. // AIP Conference Proceedings;2000, Vol. 549 Issue 1, p495 

    Abstract. The charge density distributions (CDD) and form factors of the medium and heavy nuclei were calculated using the radial wave functions of the harmonic oscillator assuming that the occupation numbers of shell states differem from 0 or 1. The occupation numbers of shell states were found...

  • Zeros in the Electromagnetic and Hadronic Form Factors. Martini, A. F.; Menon, M. J.; Montanha, J. // AIP Conference Proceedings;2004, Vol. 739 Issue 1, p578 

    We discuss the evidences for the existence of zeros in the electric and in the hadronic form factors of the proton. We show that the shapes of both form factors are similar, but there is indication that the hadronic form factors can depend on the energy. © 2004 American Institute of Physics

  • High Precision Measurement of the Proton Elastic Form Factor Ratio at Low Q2. Xiaohui Zhan // AIP Conference Proceedings;12/17/2009, Vol. 1182 Issue 1, p929 

    A high precision measurement of the proton elastic form factor ratio μpGEp/GMp in the range Q2 = 0.3–0.7 GeV2/c2 was performed using recoil polarimetry in Jefferson Lab Hall A. In this low Q2 range, previous data from LEDEX [5] along with many fits and calculations [2, 3, 4] indicate...

  • Determination of the most appropriate form factor equation for Cupresus sempervirence L. var horizentalis in the north of Iran. Kalantari, Hassan; Fallah, Asghar; Hodjati, Seyed Mohammad; Parsakhoo, Aidin // Advances in Applied Science Research;Apr2012, Vol. 3 Issue 2, p644 

    To determine the best form factor equation for Cupresus semervirence afforestation in Abbas Abad of Behshahr, numbers of 40 trees were selected in terms of their diameter classes, from 8 to 16 cm in 2 cm diameter classes. Then diameter at breast height (1.3 m), diameter at 0.65 m and diameter at...

  • On the Neutrino Vector and Axial Vector Charge Radius. Nardi, Enrico // AIP Conference Proceedings;2003, Vol. 670 Issue 1, p118 

    A Majorana neutrino is characterized by just one flavor diagonal electromagnetic form factor: the anapole moment, that in the static limit corresponds to the axial vector charge radius 〈r[SUP2,SUBA]〉. As is the case for the vector charge radius of a Dirac neutrino, proving that this...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics