问题2：γ*p→Δ+(1232)→pπ0跃迁中四极矩强度的依赖性。
Q2 Dependence of quadrupole strength in the gamma*p --> Delta(+)(1232) --> p pi(0) transition.
作者信息
Joo K, Smith L C, Burkert V D, Minehart R, Aznauryan I G, Elouadrhiri L, Stepanyan S, Adams G S, Amaryan M J, Anciant E, Anghinolfi M, Armstrong D S, Asavapibhop B, Audit G, Auger T, Avakian H, Barrow S, Bagdasaryan H, Battaglieri M, Beard K, Bektasoglu M, Bertozzi W, Bianchi N, Biselli A S, Boiarinov S, Bonner B E, Brooks W K, Calarco J R, Capitani G P, Carman D S, Carnahan B, Cole P L, Coleman A, Cords D, Corvisiero P, Crabb D, Crannell H, Cummings J, De Sanctis E, De Vita R, Degtyarenko P V, Demirchyan R A, Denizli H, Dennis L C, Deppman A, Dharmawardane K V, Dhuga K S, Djalali C, Dodge G E, Doughty D, Dragovitsch P, Dugger M, Dytman S, Eckhause M, Efremenko Y V, Egiyan H, Egiyan K S, Farhi L, Feuerbach R J, Ficenec J, Fissum K, Forest T A, Funsten H, Gai M, Gavrilov V B, Gilad S, Gilfoyle G P, Giovanetti K L, Girard P, Griffioen K A, Guidal M, Guillo M, Gyurjyan V, Hancock D, Hardie J, Heddle D, Heisenberg J, Hersman F W, Hicks K, Hicks R S, Holtrop M, Hyde-Wright C E, Ito M M, Jenkins D, Kelley J H, Khandaker M, Kim K Y, Kim W, Klein A, Klein F J, Klusman M, Kossov M, Kuang Y, Kuhn S E, Laget J M, Lawrence D, Longhi A, Loukachine K, Lucas M, Major R W, Manak J J, Marchand C, Matthews S K, McAleer S, McNabb J W C, Mecking B A, Mestayer M D, Meyer C A, Mirazita M, Miskimen R, Muccifora V, Mueller J, Mutchler G S, Napolitano J, Niculescu G, Niczyporuk B, Niyazov R A, Ohandjanyan M S, Opper A, Patois Y, Peterson G A, Philips S, Pivnyuk N, Pocanic D, Pogorelko O, Polli E, Preedom B M, Price J W, Qin L M, Raue B A, Reolon A R, Riccardi G, Ricco G, Ripani M, Ritchie B G, Ronchetti F, Rossi P, Rowntree D, Rubin P D, Salgado C W, Sanzone M, Sapunenko V, Sargsyan M, Schumacher R A, Sharabian Y G, Shaw J, Shuvalov S M, Skabelin A, Smith E S, Smith T, Sober D I, Spraker M, Stoler P, Taiuti M, Taylor S, Tedeschi D, Thompson R, Todor L, Tung T Y, Vineyard M F, Vlassov A, Weller H, Weinstein L B, Welsh R, Weygand D P, Whisnant S, Witkowski M, Wolin E, Yegneswaran A, Yun J, Zhou Z, Zhao J
机构信息
University of Virginia, Department of Physics, Charlottesville, Virginia 22903, USA.
出版信息
Phys Rev Lett. 2002 Mar 25;88(12):122001. doi: 10.1103/PhysRevLett.88.122001. Epub 2002 Mar 6.
Models of baryon structure predict a small quadrupole deformation of the nucleon due to residual tensor forces between quarks or distortions from the pion cloud. Sensitivity to quark versus pion degrees of freedom occurs through the Q2 dependence of the magnetic (M1+), electric (E1+), and scalar (S1+) multipoles in the gamma*p-->Delta(+)-->p pi(0) transition. We report new experimental values for the ratios E(1+)/M(1+) and S(1+)/M(1+) over the range Q2 = 0.4-1.8 GeV2, extracted from precision p(e,e(')p)pi(0) data using a truncated multipole expansion. Results are best described by recent unitary models in which the pion cloud plays a dominant role.
重子结构模型预测，由于夸克之间的残余张量力或π介子云的畸变，核子会有微小的四极形变。在γ*p→Δ(+)→pπ(0)跃迁中，对夸克与π介子自由度的敏感度通过磁（M1+）、电（E1+）和标量（S1+）多极子的Q2依赖性体现。我们报告了在Q2 = 0.4 - 1.8 GeV2范围内E(1+)/M(1+)和S(1+)/M(1+)比值的新实验值，这些值是使用截断多极展开从精确的p(e,e(')p)π(0)数据中提取的。结果最好由π介子云起主导作用的近期幺正模型来描述。
Zotero 插件