Abstract: While the third run of the Large Hadron Collider (LHC) is ongoing, the underlying theory that extends the Standard Model remains so far unknown. Left-Right Models (LRMs) introduce a new gauge sector, and can restore parity symmetry at high enough energies. If LRMs are indeed realized in nature, the mediators of the new weak force can be searched for in colliders via their direct production. We recast existing experimental limits from the LHC Run 2 and derive generic bounds on the masses of the heavy LRM gauge bosons. As a novelty, we discuss the dependence of the WR and ZR total width on the LRM scalar content, obtaining model-independent bounds within the specific realizations of the LRM scalar sectors analysed here. These bounds avoid the need to detail the spectrum of the scalar sector, and apply in the general case where no discrete symmetry is enforced. Moreover, we emphasize the impact on the WR production at LHC of general textures of the right-handed quark mixing matrix without manifest left-right symmetry. We find that the WR and ZR masses are constrained to lie above 2 TeV and 4 TeV, respectively.

Abstract: While the hunt for new states beyond the standardmodel (SM) goes on for various well motivated theories, the leptoquarks are among the most appealing scenarios at recent times due to a series of tensions observed in B-meson decays. We consider SU(2) singlet and triplet scalar leptoquarks separately, which contribute to charged and neutral current B-meson decays. Focusing on the single production of these two scalar leptoquarks, we perform a PYTHIA-based simulation considering all the dominant SM backgrounds at the current and future setups of the Large Hadron Collider (LHC). The mono-b-jet + p(T) finalstate gives the strongest signal for the singlet leptoquark at the 30 TeV LHC or Future Circular Collider (FCC), with a possibility of 5 sigma signal significance with greater than or similar to 1000 fb(-1) of integrated luminosity, for the chosen benchmark scenarios. The finalstate consisting of a c-jet and two tau-jets provides highest reach for the singlet leptoquark, probing an O(10(-1)) value of the Yukawa-type couplings for up to 3.0 TeV leptoquark mass. For the triplet leptoquark, 1 – jet + 2 μ+ p(T) topology is the most optimistic signature at the LHC, probing leptoquark couplings to fermions at O(10(-1)) value for the leptoquark mass range up to 4.0 TeV. The invariant mass edge distribution is found to be instrumental in determination of the leptoquarkmass scale at the LHC. We also perform the analysis at the proposed multiTeV muon collider, where an O(10(-1)) leptoquark Yukawa coupling can be probed for a 5.0 TeV leptoquark mass.

Abstract: When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning(1); this phenomenon has been a mystery in nuclear physics for over 40 years(2,3). The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum(4-12). Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the gamma-ray heating problem in nuclear reactors(13,14), for the study of the structure of neutron-rich isotopes(15,16), and for the synthesis and stability of super-heavy elements(17,18). gamma-ray spectroscopy experiments on the origin of spin in the products of nuclear fission of spin-zero nuclei suggest that the fission fragments acquire their spin after scission, rather than before.