Buonocore Luca, Haisch Ulrich, Nason Paolo, Tramontano Francesco, Zanderighi Giulia
Dipartimento di Fisica, Università di Napoli Federico II and INFN, Sezione di Napoli, I-80126 Napoli, Italy.
Physik Institut, Universität Zürich, CH-8057 Zürich, Switzerland.
Phys Rev Lett. 2020 Dec 4;125(23):231804. doi: 10.1103/PhysRevLett.125.231804.
Processes commonly studied at the Large Hadron Collider (LHC) are induced by quarks and gluons inside the protons of the LHC beams. In this Letter, we demonstrate that, since protons also contain leptons, it is possible to target lepton-induced processes at the LHC as well. In particular, by picking a lepton from one beam and a quark from the other beam, we present for the first time a comprehensive analysis of resonant single leptoquark (LQ) production at a hadron collider. In the case of minimal scalar LQs, we derive novel bounds that arise from the LHC Run II considering all possible flavor combinations of an electron or a muon and an up (u), a down (d), a strange, or a charm quark. For the flavor combinations with a u or a d quark, the obtained limits represent the most stringent constraints to date on LQs of this type. The prospects of our method at future LHC runs are also explored. Given the discovery reach of the proposed LQ signature, we argue that dedicated resonance searches in final states featuring a single light lepton and a single light-flavor jet should be added to the exotics search canon of both the ATLAS and the CMS Collaborations.
大型强子对撞机（LHC）中通常研究的过程是由LHC束流质子内部的夸克和胶子引发的。在本论文中，我们证明，由于质子中也含有轻子，因此在LHC中也能够针对轻子引发的过程展开研究。具体而言，通过从一束流中选取一个轻子，从另一束流中选取一个夸克，我们首次对强子对撞机中共振单轻夸克（LQ）产生进行了全面分析。对于最小标量LQ的情况，我们考虑电子或μ子与上夸克（u）、下夸克（d）、奇夸克或粲夸克的所有可能味组合，推导出了来自LHC Run II的新限制。对于与u或d夸克的味组合，所获得的限制是迄今为止对这类LQ最严格的约束。我们还探讨了我们的方法在未来LHC运行中的前景。鉴于所提议的LQ信号的发现范围，我们认为在ATLAS和CMS合作组的奇异粒子搜索标准中，应增加在具有单个轻子和单个轻味喷注的末态中进行专门的共振搜索。
