How strange is pion electroproduction?

详细信息    查看全文

• 作者：Mikhail Gorchtein^a ; ^{gorshtey@kph.uni-mainz.de" class="auth_mail" title="E-mail the corresponding author} ; Hubert Spiesberger^b ; ^c ; ^{spiesber@uni-mainz.de" class="auth_mail" title="E-mail the corresponding author} ; Xilin Zhang^d ; ^{xilinz@uw.edu" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Physics Letters B
• 出版年：2016
• 出版时间：10 January 2016
• 年：2016
• 卷：752
• 期：Complete
• 页码：135-145
• 全文大小：732 K

文摘

We consider pion production in parity-violating electron scattering (PVES) in the presence of nucleon strangeness in the framework of partial wave analysis with unitarity. Using the experimental bounds on the strange form factors obtained in elastic PVES, we study the sensitivity of the parity-violating asymmetry to strange nucleon form factors. For forward kinematics and electron energies above 1 GeV, we observe that this sensitivity may reach about 20% in the threshold region. With parity-violating asymmetries being as large as tens p.p.m., this study suggests that threshold pion production in PVES can be used as a promising way to better constrain strangeness contributions. Using this model for the neutral current pion production, we update the estimate for the dispersive γZ  -box correction to the weak charge of the proton. In the kinematics of the Qweak experiment, our new prediction reads class="mathmlsrc">title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315008862&_mathId=si1.gif&_user=111111111&_pii=S0370269315008862&_rdoc=1&_issn=03702693&md5=7a98950744b1466a02599d3f16b8d6b0">class="imgLazyJSB inlineImage" height="20" width="287" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269315008862-si1.gif">class="mathContainer hidden">class="mathCode">$\mathrm{Re}{\square }_{\gamma Z}^V(E=1.165\text{GeV})=(5.58\pm 1.41)\times {10}^{-3}$, an improvement over the previous uncertainty estimate of class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315008862&_mathId=si2.gif&_user=111111111&_pii=S0370269315008862&_rdoc=1&_issn=03702693&md5=97b816f4579c75f24423040c54fb7695" title="Click to view the MathML source">±2.0×10⁻³class="mathContainer hidden">class="mathCode">$\pm 2.0\times {10}^{-3}$. Our new prediction in the kinematics of the upcoming MESA/P2 experiment reads class="mathmlsrc">title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315008862&_mathId=si3.gif&_user=111111111&_pii=S0370269315008862&_rdoc=1&_issn=03702693&md5=312a401dc431302911ea9cad5aff8c8a">class="imgLazyJSB inlineImage" height="20" width="272" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269315008862-si3.gif">class="mathContainer hidden">class="mathCode">$\mathrm{Re}{\square }_{\gamma Z}^V(E=0.155\text{GeV})=(1.1\pm 0.2)\times {10}^{-3}$.