BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Quark counting rules for the production of cumulative pions with l arge transverse momenta DTSTART;VALUE=DATE-TIME:20241025T061500Z DTEND;VALUE=DATE-TIME:20241025T063000Z DTSTAMP;VALUE=DATE-TIME:20260314T060320Z UID:indico-contribution-4320@cern.ch DESCRIPTION:Speakers: Semyon Yurchenko (Saint Petersburg State University\ , Laboratory of ulta-high energy physics)\nThis work focuses on the calcul ation of quark counting rules for the inclusive production of pions at lar ge transverse momenta in the cumulative region—a kinematic domain forbid den for single nucleon-nucleon interactions. This region\, which cannot be accessed through single nucleon-nucleon interactions\, becomes relevant i n nuclear collisions and can be observed using the MPD and SPD detectors a t the NICA complex. Unlike high-energy colliders like RHIC and LHC\, where this phenomenon cannot be studied due to kinematic limitations\, the inte rmediate energy collisions at NICA provide a distinctive opportunity to in vestigate these cumulative effects in detail.\n\nThe concept of the flucto n\, a cluster of cold\, dense quark-gluon matter with high baryon density\ , plays a central role in this context. From a modern perspective\, flucto ns are seen as temporary\, highly localized concentrations of quarks and g luons within the colliding nuclei\, and their presence enables the product ion of cumulative particles during the collision. If a flucton is present during nucleon collisions\, it can trigger the production of particles tha t exhibit unusual kinematic properties\, including those with large transv erse momenta at mid-rapidities.\n\nBuilding on the earlier work of V. V. V echernin and M. A. Braun [1-4]\, who developed a microscopic quark-parton model for particle production in the fragmentation region of one of the co lliding nuclei\, we extend this framework to the new kinematic region char acterized by high transverse momentum. In this extended region\, we observ e a shift in the proton-to-pion yield ratio when compared to cumulative pa rticle production in the traditional fragmentation region. This is largely due to the different underlying mechanisms of particle formation: while c umulative protons are predominantly formed through the coherent recombinat ion of three quarks from a flucton\, cumulative pions are primarily produc ed via the fragmentation of a single quark [3\, 4\, 9]. We compare the ob tained theoretical results with the results of our preliminary estimates o f particle yields in this region based on a more phenomenological approach [5-7].\n\nMoreover\, our work reveals the potential for studying flucton- flucton interactions—a rare and intriguing process—in the new cumulati ve region at mid-rapidities. Unlike the fragmentation region\, where such interactions are impossible to observe\, this region opens up the possibil ity for detailed experimental investigation. Notably\, this process can be explored in detail using dd (deuteron-deuteron) collisions at the NICA SP D\, where both deuterons may exist as flucton states at the moment of coll ision. In this scenario\, the absence of additional nucleon-nucleon intera ctions reduces background\, simplifying the detection of cumulative partic les in correlation with those originating from flucton fragmentation [8]. The higher collision rate at SPD compared to MPD also enhances the likelih ood of observing rare cumulative events\, making SPD a particularly valuab le tool for these studies.\n\nThe work was supported by the Russian Scienc e Foundation grant 23-12-00042.\n\n1. M.A. Braun\, V.V. Vechernin\, Nucl. Phys. B 427\, 614-640 (1994).\n2. M.A. Braun\, V.V. Vechernin\, Phys. Atom . Nucl. 63\, 1831-1834 (2000).\n3. M.A. Braun\, V.V. Vechernin\, Theor. Ma th. Phys. 139\, 766-786 (2004).\n4. V.V. Vechernin\, AIP Conf. Proc. 1707\ , 060020 (2016).\n5. V.V. Vechernin\, Phys. Part. Nuclei 52\, 604-608 (202 1).\n6. V.I. Zherebchevsky\, V.P. Kondratiev\, V.V. Vechernin\, S.N. Igolk in\,\nNuclear Inst. and Methods in Physics Research A 985\, 164668 (2021). \n7. V.V. Vechernin\, Phys. Part. Nuclei 53\, 433-440 (2022).\n8. V. Veche rnin\, S. Belokurova\, S. Yurchenko\, Symmetry 16\, 79 (2024). \n9. V.V. Vechernin\, Phys. Part. Nuclei 54\, 528-535 (2023).\n\nhttps://indico.part icle.mephi.ru/event/436/contributions/4320/ LOCATION: Moskvorechye 2 URL:https://indico.particle.mephi.ru/event/436/contributions/4320/ END:VEVENT END:VCALENDAR