Separated response function ratios in exclusive, forward π(±) electroproduction.

Autor: Huber GM; University of Regina, Regina, Saskatchewan S4S 0A2, Canada., Blok HP; VU university, NL-1081 HV Amsterdam, The Netherlands and NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, The Netherlands., Butuceanu C; University of Regina, Regina, Saskatchewan S4S 0A2, Canada., Gaskell D; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Horn T; Catholic University of America, Washington, DC 20064, USA., Mack DJ; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Abbott D; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Aniol K; California State University Los Angeles, Los Angeles, California 90032, USA., Anklin H; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Florida International University, Miami, Florida 33119, USA., Armstrong C; College of William and Mary, Williamsburg, Virginia 23187, USA., Arrington J; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Assamagan K; Hampton University, Hampton, Virginia 23668, USA., Avery S; Hampton University, Hampton, Virginia 23668, USA., Baker OK; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA., Barrett B; Saint Mary's University, Halifax, Nova Scotia B3H 3C3 Canada., Beise EJ; University of Maryland, College Park, Maryland 20742, USA., Bochna C; University of Illinois, Champaign, Illinois 61801, USA., Boeglin W; Florida International University, Miami, Florida 33119, USA., Brash EJ; University of Regina, Regina, Saskatchewan S4S 0A2, Canada., Breuer H; University of Maryland, College Park, Maryland 20742, USA., Chang CC; University of Maryland, College Park, Maryland 20742, USA., Chant N; University of Maryland, College Park, Maryland 20742, USA., Christy ME; Hampton University, Hampton, Virginia 23668, USA., Dunne J; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Eden T; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Norfolk State University, Norfolk, Virginia 23504, USA., Ent R; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Fenker H; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Gibson EF; California State University, Sacramento, California 95819, USA., Gilman R; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA., Gustafsson K; University of Maryland, College Park, Maryland 20742, USA., Hinton W; Hampton University, Hampton, Virginia 23668, USA., Holt RJ; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Jackson H; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Jin S; Kyungpook National University, Daegu 702-701, Republic of Korea., Jones MK; College of William and Mary, Williamsburg, Virginia 23187, USA., Keppel CE; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA., Kim PH; Kyungpook National University, Daegu 702-701, Republic of Korea., Kim W; Kyungpook National University, Daegu 702-701, Republic of Korea., King PM; University of Maryland, College Park, Maryland 20742, USA., Klein A; Old Dominion University, Norfolk, Virginia 23529, USA., Koltenuk D; University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA., Kovaltchouk V; University of Regina, Regina, Saskatchewan S4S 0A2, Canada., Liang M; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Liu J; University of Maryland, College Park, Maryland 20742, USA., Lolos GJ; University of Regina, Regina, Saskatchewan S4S 0A2, Canada., Lung A; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Margaziotis DJ; California State University Los Angeles, Los Angeles, California 90032, USA., Markowitz P; Florida International University, Miami, Florida 33119, USA., Matsumura A; Tohoku University, Sendai, Japan., McKee D; New Mexico State University, Las Cruces, New Mexico 88003-8001, USA., Meekins D; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Mitchell J; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Miyoshi T; Tohoku University, Sendai, Japan., Mkrtchyan H; A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia., Mueller B; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Niculescu G; James Madison University, Harrisonburg, Virginia 22807, USA., Niculescu I; James Madison University, Harrisonburg, Virginia 22807, USA., Okayasu Y; Tohoku University, Sendai, Japan., Pentchev L; College of William and Mary, Williamsburg, Virginia 23187, USA., Perdrisat C; College of William and Mary, Williamsburg, Virginia 23187, USA., Pitz D; DAPNIA/SPhN, CEA/Saclay, F-91191 Gif-sur-Yvette, France., Potterveld D; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Punjabi V; Norfolk State University, Norfolk, Virginia 23504, USA., Qin LM; Old Dominion University, Norfolk, Virginia 23529, USA., Reimer PE; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Reinhold J; Florida International University, Miami, Florida 33119, USA., Roche J; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Roos PG; University of Maryland, College Park, Maryland 20742, USA., Sarty A; Saint Mary's University, Halifax, Nova Scotia B3H 3C3 Canada., Shin IK; Kyungpook National University, Daegu 702-701, Republic of Korea., Smith GR; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Stepanyan S; A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia., Tang LG; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and Hampton University, Hampton, Virginia 23668, USA., Tadevosyan V; A.I. Alikhanyan National Science Laboratory, Yerevan 0036, Armenia., Tvaskis V; VU university, NL-1081 HV Amsterdam, The Netherlands and NIKHEF, Postbus 41882, NL-1009 DB Amsterdam, The Netherlands., van der Meer RL; University of Regina, Regina, Saskatchewan S4S 0A2, Canada., Vansyoc K; Old Dominion University, Norfolk, Virginia 23529, USA., Van Westrum D; University of Colorado, Boulder, Colorado 80309, USA., Vidakovic S; University of Regina, Regina, Saskatchewan S4S 0A2, Canada., Volmer J; VU university, NL-1081 HV Amsterdam, The Netherlands and DESY, Hamburg, Germany., Vulcan W; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Warren G; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Wood SA; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Xu C; University of Regina, Regina, Saskatchewan S4S 0A2, Canada., Yan C; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA., Zhao WX; Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA., Zheng X; Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA., Zihlmann B; Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA and University of Virginia, Charlottesville, Virginia 22901, USA.
Jazyk: angličtina
Zdroj: Physical review letters [Phys Rev Lett] 2014 May 09; Vol. 112 (18), pp. 182501. Date of Electronic Publication: 2014 May 05.
DOI: 10.1103/PhysRevLett.112.182501
Abstrakt: The study of exclusive π(±) electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio RL=σL(π-)/σL(π+) is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of RT=σT(π-)/σT(π+) from unity at small -t, to 1/4 at large -t, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier approach to perturbative QCD than the individual cross sections. We have performed the first complete separation of the four unpolarized electromagnetic structure functions above the dominant resonances in forward, exclusive π(±) electroproduction on the deuteron at central Q(2) values of 0.6, 1.0, 1.6  GeV(2) at W=1.95  GeV, and Q(2)=2.45  GeV(2) at W=2.22  GeV. Here, we present the L and T cross sections, with emphasis on RL and RT, and compare them with theoretical calculations. Results for the separated ratio RL indicate dominance of the pion-pole diagram at low -t, while results for RT are consistent with a transition between pion knockout and quark knockout mechanisms.
Databáze: MEDLINE