First measurement of the strange axial coupling constant using neutral-current quasielastic interactions of atmospheric neutrinos at KamLAND

• DOI: 10.48550/arxiv.2211.13911
• Publication Date: 2022-01-01
• Authors: KamLAND Collabora...; S. Abe; S. Asami; M. Eizuka; S. Futagi; A. Gando; Y. Gando; T. Gima; A. Goto; T. Hachiya; K. Hata; K. Ichimura; S. Ieki; H. Ikeda; K. Inoue; K. Ishidoshiro; Y. Kamei; N. Kawada; Y. Kishimoto; M. Koga; M. Kurasawa; T. Mitsui; H. Miyake; T. Nakahata; K. Nakamura; R. Nakamura; H. Ozaki; T. Sakai; I. Shimizu; J. Shirai; K. Shiraishi; A. Suzuki; Y. Suzuki; A. Takeuchi; K. Tamae; H. Watanabe; Y. Yoshida; S. Obara; A. K. Ichikawa; S. Yoshida; S. Umehara; K. Fushimi; K. Kotera; Y. Urano; B. E. Berger; B. K. Fujikawa; J. G. Learned; J. Maricic; S. N. Axani; Z. Fu; J. Smolsky; L. A. Winslow; Y. Efremenko; H. J. Karwowski; D. M. Markoff; W. Tornow; J. A. Detwiler; S. Enomoto; M. P. Decowski; C. Grant; A. Li; H. Song; S. Dell'Oro; T. O'Donnell
• Keywords: Coupling constant; Neutral current; Multiplicity (mathematics); Weak interaction

We report a measurement of the strange axial coupling constant $g_A^s$ using atmospheric neutrino data at KamLAND. This is component form factor neutral-current quasielastic (NCQE) interaction. The value significantly changes ratio proton and neutron NCQE cross sections. KamLAND suitable for measuring interactions as it can detect nucleon recoils with low-energy thresholds measure multiplicity high efficiency. data, including information on associated interactions, makes possible to suppressed dependence mass $M_A$, which has not yet been determined. For comprehensive prediction emission we establish simulation particle via nuclear deexcitation $^{12}$C, process considered in existing Monte Carlo event generators. Energy spectrum fitting each gives $g_A^s =-0.14^{+0.25}_{-0.26}$, most stringent limit obtained without $M_A$ constraints. two-body current contribution this analysis relies theoretically effective model electron scattering experiments requires future verification by direct measurements improvement.