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Title: Beam normal spin asymmetry for the ep→eΔ(1232) process

Journal Article · · Physical Review D
 [1];  [2];  [3];  [4]
  1. College of William and Mary, Williamsburg, VA (United States)
  2. Univ. degli Studie di Pavia, Pavia (Italy); INFN Sezione di Pavia, Pavia (Italy)
  3. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  4. Johannes Gutenberg Univ., Mainz (Germany)
+ Show Author Affiliations

Here, we calculate the single spin asymmetry for the $$e p \to e \Delta(1232)$$ process, for an electron beam polarized normal to the scattering plane. Such single spin asymmetries vanish in the one-photon exchange approximation, and are directly proportional to the absorptive part of a two-photon exchange amplitude. As the intermediate state in such two-photon exchange process is on its mass shell, the asymmetry allows one to access for the first time the on-shell $$\Delta \to \Delta$$ as well as $$N^\ast \to \Delta$$ electromagnetic transitions. We present the general formalism to describe the $$e p \to e \Delta$$ beam normal spin asymmetry, and provide a numerical estimate of its value using the nucleon, $$\Delta(1232)$$, $$S_{11}(1535)$$, and $$D_{13}(1520)$$ intermediate states. We compare our results with the first data from the Qweak@JLab experiment and give predictions for the A4@MAMI experiment.

Research Organization:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Nuclear Physics (NP); USDOE
Grant/Contract Number:
PHY-1516509; AC05-06OR23177; FG02-87ER40365
OSTI ID:
1416140
Alternate ID(s):
OSTI ID: 1414850
Report Number(s):
JLAB-THY-17-2630; DOE/OR/23177-4301; arXiv:1708.05316; PRVDAQ; TRN: US1800882
Journal Information:
Physical Review D, Vol. 96, Issue 11; ISSN 2470-0010
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 14 works
Citation information provided by
Web of Science

References (49)

Unitary isobar model --MAID2007 journal October 2007
Electromagnetic form factors of spin-⅓ baryons journal November 1990
Review of Particle Physics journal October 2016
Electron beam single-spin asymmetries in the resonance region with final hadrons observed journal April 2016
Quark transverse charge densities in the from lattice QCD journal June 2009
Magnetic dipole moment of the Δ + ( 1232 ) from the γ p → γ π 0 p reaction journal November 2001
Virtual Compton scattering off the nucleon journal January 1998
Field theory of nucleon to higher-spin baryon transitions journal September 1999
Erratum to “Field-theoretical description of electromagnetic Δ resonance production and determination of the magnetic moment of the Δ+(1232) resonance by the ep→e′N′π′γ′ and γp→N′π′γ′ reaction” journal April 2001
Inelastic photon scattering and the magnetic moment of the Δ (1232) resonance journal July 2000
Beam normal spin asymmetry in elastic lepton–nucleon scattering journal September 2004
Multipole γN-Δ form factors and resonant photo- and electroproduction journal November 1973
Magnetic Moment of the Δ ( 1232 ) Resonance in Chiral Effective-Field Theory journal March 2005
New Measurements of the Beam Normal Spin Asymmetries at Large Backward Angles with Hydrogen and Deuterium Targets journal July 2017
Elastic scattering of electrons from polarized protons and inelastic electron scattering experiments journal December 1971
Measurement of the vector analyzing power in elastic electron-proton scattering as a probe of the double virtual Compton amplitude journal May 2001
Lattice calculation of the magnetic moments of Δ and Ω − baryons with dynamical clover fermions journal March 2009
Quantization of an interacting spin- 3 2 field and the Δ isobar journal September 1998
Radiative π0 photoproduction on protons in the Δ+ (1232) region journal February 2010
Baryon charge radii and quadrupole moments in the 1 / N c expansion: The 3-flavor case journal January 2003
Low-Energy Measurements of the Weak Mixing Angle journal October 2013
Chiral symmetry and the axial nucleon to Δ ( 1232 ) transition form factors journal November 2008
Two-Photon Physics in Hadronic Processes journal November 2007
Chiral symmetry and the delta-nucleon transition form factors journal August 1999
Nucleon and Δ ( 1232 ) form factors at low momentum transfer and small pion masses journal February 2012
Electromagnetic excitation of nucleon resonances journal September 2011
Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering journal August 2007
Δ -baryon electromagnetic form factors in lattice QCD journal January 2009
Baryon magnetic moments in the expansion journal September 1994
New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei journal November 2012
Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasielastic Electron-Deuteron Scattering journal July 2011
Decays of ℓ=1 baryons to Δγ journal November 1998
Chiral effective-field theory in the Δ ( 1232 ) region. II. Radiative pion photoproduction journal January 2008
Complete analysis of baryon magnetic moments in the 1 / N c expansion journal July 2004
The Reaction γ p → π 0 γ ′ p and the Magnetic Dipole Moment of the Δ + ( 1232 ) Resonance journal December 2002
Isobar configurations in nuclei journal February 1978
Studies of Nucleon Resonance Structure in Exclusive Meson Electroproduction journal June 2013
Colloquium : The Shape of Hadrons journal September 2012
Preliminary beam normal single spin asymmetry results from Qweak
  • Waidyawansa, Buddhini P.
  • 11TH CONFERENCE ON THE INTERSECTIONS OF PARTICLE AND NUCLEAR PHYSICS: (CIPANP 2012), AIP Conference Proceedings https://doi.org/10.1063/1.4826847
conference January 2013
New physics and the proton radius problem journal August 2012
Electromagnetic excitation of the Δ(1232)-resonance journal January 2007
Signatures of chiral dynamics in the nucleon to Delta transition⋆ journal April 2006
Field-theoretical description of electromagnetic Δ resonance production and determination of the magnetic moment of the Δ+ (1232) resonance by the ep → e′N′π′γ′ and γp → N′π′γ′ reactions journal February 1999
Measurement of the Target-Normal Single-Spin Asymmetry in Quasielastic Scattering from the Reaction He 3 ↑ ( e , e ′   ) journal October 2015
Contributions from γ Z box diagrams to parity violating elastic e − p scattering journal June 2011
Unitary model for the γ p → γ π 0 p reaction and the magnetic dipole moment of the Δ + ( 1232 ) journal January 2005
Measurement of the Transverse Beam Spin Asymmetry in Elastic Electron-Proton Scattering and the Inelastic Contribution to the Imaginary Part of the Two-Photon Exchange Amplitude journal March 2005
Resonance estimates for single spin asymmetries in elastic electron-nucleon scattering journal October 2004
Large N c , constituent quarks, and N , Δ charge radii journal October 2000

Cited By (2)

Lepton mass effects for beam-normal single-spin asymmetry in elastic muon-proton scattering journal November 2019
Lepton mass effects for beam-normal single-spin asymmetry in elastic muon-proton scattering text January 2019

Figures / Tables (9)

Figure-1(p. 3)figure Figure-1
Figure 2(p. 5)figure Figure 2
Δ process. The upper panel shows the phase-space regions for different c.m. angles θ cm as indicated on the ellipses for E e = 0.855     GeV ( s=2.485  GeV2 ), and for W = 0.9383     GeV (i.e. for a nucleon intermediate state). The lower panel shows the allowed values of the photon virtualities for different intermediate states for θ cm = 30 ° . We show three cases corresponding with the contribution of N , Δ(1232) and S 11 (1535) excitations. The accessible regions correspond with the interior of the ellipses. The intersection with the axes corresponds with quasi-VCS, whereas the situation at W= s − m e where all ellipses shrink to the point Q 1 2 = Q 2 2 ≃0 corresponds with quasi-RCS." data-ostiid="1416140">
Figure 3(p. 6)figure Figure 3
Figure-4(p. 13)figure Figure-4
Δ intermediate state contribution for E e =0.855  GeV . The upper and lower panels show the distribution for θ cm =30 deg and θ cm =150 deg, respectively. The integrand takes zero value along the dashed curve. Larger negative (positive) values of I correspond with stronger shades of blue (red). The distance between the contours corresponds with 0.5×10 − 7 for the upper panel and 0.5×10 − 6 for the bottom panel." data-ostiid="1416140">
Figure-5(p. 14)figure Figure-5
Δ+ process as a function of the lab scattering angle for a beam energy E e =1.165  GeV . The curves denote the contributions from different intermediate states: nucleon (dashed-dotted red curve), Δ(1232) (dashed blue curve), S 11 (1535)+ D 13 (1520) (dotted violet curve), and N+Δ+ S 11 (1535)+ D 13 (1520) (solid black curve). The data point is from the Qweak Collaboration [38]." data-ostiid="1416140">
Figure-6(p. 14)figure Figure-6
Δ+ process as function of the lab scattering angle for a beam energy E e =0.855  GeV where data have been taken by the A4@MAMI experiment [32, 33]. The curves denote the contributions from different intermediate states: nucleon (dashed-dotted red curve), Δ(1232) (dashed blue curve), S 11 (1535)+ D 13 (1520) (dotted violet curve), and N+Δ+ S 11 (1535)+ D 13 (1520) (solid black curve)." data-ostiid="1416140">
Figure-7(p. 15)figure Figure-7
Δ+ process as a function of the lab scattering angle, for beam energies in the Δ -resonance region where data have been taken by the A4@MAMI experiment [32, 33]. Upper panel: E e =0.420  GeV ; lower panel: E e =0.570  GeV . The curves denote the contributions from different intermediate states: nucleon (dashed-dotted red curves), Δ(1232) (dashed blue curves), and N+Δ (solid black curves)." data-ostiid="1416140">
Figure-8(p. 15)figure Figure-8
Δ+ process at E e =0.570  GeV on the Δ+ magnetic dipole moment. The curves denote the contributions from N+Δ intermediate states for different values of μ Δ [in units of e/(2 M Δ ) ]: μ Δ =1.5 (blue dashed curve), μ Δ =3.0 (black solid curve), and μ Δ =4.5 (red dashed-dotted curve)." data-ostiid="1416140">
Figure-9(p. 16)figure Figure-9

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