Longitudinal and transverse spin transfer to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="normal">Λ</mml:mi></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mover accent="true"><mml:mi mathvariant="normal">Λ</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover></mml:math> hyperons in polarized <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mo>+</mml:mo><mml:mi>p</mml:mi></mml:math> collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>200</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>GeV</mml:mi></mml:math>
M. I. Abdulhamid, B. E. Aboona, J. Adam, L. Adamczyk, J. R. Adams, Y. Hu, M. M. Aggarwal, Z. Ahammed, D. M. Anderson, E. C. Aschenauer, Saba Aslam, J. Atchison, V. Bairathi, W. Baker, J. Ball, K. N. Barish, R. Bellwied, P. Bhagat, A. Bhasin, S. Bhatta, J. Bielčík, J. Bielčíková, J. D. Brandenburg, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, J. Ceska, I. Chakaberia, P. Chaloupka, B. K. Chan, Z. Chang, A. Chatterjee, D. Chen, J. Chen, J. H. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, G. Dale-Gau, Arkaprava Das, M. Daugherity, I. M. Deppner, A. Dhamija, L. Di Carlo, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, C. Feng, Y. Feng, E. Finch, Y. Fisyak, F. Flor, Changbo Fu, C. A. Gagliardi, T. Galatyuk, Tong Gao, F. J. M. Geurts, N. Ghimire, S. M. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, W. Guryn, A. Hamed, Y. Han, S. Harabasz, M. D. Harasty, J. W. Harris, H. Harrison-Smith, W. He, X. H. He, Y. He, N. Herrmann, L. Holub, C. Hu, Q. Hu, Y. Hu, H. Z. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang
Abstract
The longitudinal and transverse spin transfers to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi mathvariant="normal">Λ</a:mi></a:math> (<d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mover accent="true"><d:mi mathvariant="normal">Λ</d:mi><d:mo stretchy="false">¯</d:mo></d:mover></d:math>) hyperons in polarized proton-proton collisions are expected to be sensitive to the helicity and transversity distributions, respectively, of (anti)strange quarks in the proton, and to the corresponding polarized fragmentation functions. We report improved measurements of the longitudinal spin transfer coefficient, <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"><i:msub><i:mi>D</i:mi><i:mrow><i:mi>L</i:mi><i:mi>L</i:mi></i:mrow></i:msub></i:math>, and the transverse spin transfer coefficient, <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"><k:msub><k:mi>D</k:mi><k:mrow><k:mi>T</k:mi><k:mi>T</k:mi></k:mrow></k:msub></k:math>, to <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"><m:mi mathvariant="normal">Λ</m:mi></m:math> and <p:math xmlns:p="http://www.w3.org/1998/Math/MathML" display="inline"><p:mover accent="true"><p:mi mathvariant="normal">Λ</p:mi><p:mo stretchy="false">¯</p:mo></p:mover></p:math> in polarized proton-proton collisions at <u:math xmlns:u="http://www.w3.org/1998/Math/MathML" display="inline"><u:msqrt><u:mi>s</u:mi></u:msqrt><u:mo>=</u:mo><u:mn>200</u:mn><u:mtext> </u:mtext><u:mtext> </u:mtext><u:mi>GeV</u:mi></u:math> by the STAR experiment at RHIC. The dataset includes longitudinally polarized proton-proton collisions with an integrated luminosity of <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"><w:mrow><w:mn>52</w:mn><w:mtext> </w:mtext><w:mtext> </w:mtext><w:msup><w:mrow><w:mi>pb</w:mi></w:mrow><w:mrow><w:mo>−</w:mo><w:mn>1</w:mn></w:mrow></w:msup></w:mrow></w:math>, and transversely polarized proton-proton collisions with a similar integrated luminosity. Both datasets have about twice the statistics of previous results and cover a kinematic range of <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"><y:mo stretchy="false">|</y:mo><y:msub><y:mi>η</y:mi><y:mrow><y:mi mathvariant="normal">Λ</y:mi><y:mo stretchy="false">(</y:mo><y:mover accent="true"><y:mi mathvariant="normal">Λ</y:mi><y:mo stretchy="false">¯</y:mo></y:mover><y:mo stretchy="false">)</y:mo></y:mrow></y:msub><y:mo stretchy="false">|</y:mo><y:mo><</y:mo><y:mn>1.2</y:mn></y:math> and transverse momentum <ib:math xmlns:ib="http://www.w3.org/1998/Math/MathML" display="inline"><ib:msub><ib:mi>p</ib:mi><ib:mrow><ib:mi>T</ib:mi><ib:mo>,</ib:mo><ib:mrow><ib:mi mathvariant="normal">Λ</ib:mi><ib:mo stretchy="false">(</ib:mo><ib:mover accent="true"><ib:mi mathvariant="normal">Λ</ib:mi><ib:mo stretchy="false">¯</ib:mo></ib:mover><ib:mo stretchy="false">)</ib:mo></ib:mrow></ib:mrow></ib:msub></ib:math> up to <qb:math xmlns:qb="http://www.w3.org/1998/Math/MathML" display="inline"><qb:mrow><qb:mn>8</qb:mn><qb:mtext> </qb:mtext><qb:mtext> </qb:mtext><qb:mi>GeV</qb:mi><qb:mo>/</qb:mo><qb:mi>c</qb:mi></qb:mrow></qb:math>. We also report the first measurements of the hyperon spin transfer coefficients <sb:math xmlns:sb="http://www.w3.org/1998/Math/MathML" display="inline"><sb:msub><sb:mi>D</sb:mi><sb:mrow><sb:mi>L</sb:mi><sb:mi>L</sb:mi></sb:mrow></sb:msub></sb:math> and <ub:math xmlns:ub="http://www.w3.org/1998/Math/MathML" display="inline"><ub:msub><ub:mi>D</ub:mi><ub:mrow><ub:mi>T</ub:mi><ub:mi>T</ub:mi></ub:mrow></ub:msub></ub:math> as a function of the fractional jet momentum <wb:math xmlns:wb="http://www.w3.org/1998/Math/MathML" display="inline"><wb:mi>z</wb:mi></wb:math> carried by the hyperon, which can provide more direct constraints on the polarized fragmentation functions. Published by the American Physical Society 2024