Grand Unified Theories (GUTs) based on groups like $SO(10)$ and $SU(5)$ unify Standard Model (SM) fermions into irreducible representations (irreps), and predict additional scalar fields beyond the SM Higgs. In $SO(10)$ GUTs, the scalar fields can arise from irreps contributing to the Yukawa sector at the renormalisable level, such as $10_{\mathrm{H}}$, $120_{\mathrm{H}}$, and $\overline{126}_{\mathrm{H}}$, or from $16_{\mathrm{H}}$ in non-renormalisable interactions. The direct implications of these scalars include the violation of baryon and lepton number, enabling processes such as nucleon decays, neutron-antineutron oscillation, and potentially accounting for the observed baryon asymmetry of the universe. We systematically analyse their couplings to SM fermions, identifying diquark and leptoquark interactions vertices involving all scalars residing in $10_{\mathrm{H}}$, $120_{\mathrm{H}}$, $\overline{126}_{\mathrm{H}}$, and $16_{\mathrm{H}}$ and comprehensively assess their contributions to nucleon decay, neutron-antineutron oscillation, quark flavour violation, and baryogenesis. Constraints on the masses of these scalars, derived from experimental bounds on the aforementioned processes, are also estimated. Conventional GUTs rely on multiple scalar irreps to avoid unrealistic fermion mass relations; for example, minimal $SU(5)$ with $5_{\mathrm{H}}$ predicts degenerate down-quark and charged-lepton masses. We demonstrate that quantum corrections from heavy scalars in a minimally extended $SU(5)$ model can lift this degeneracy, thereby reducing the arbitrariness in the scalar sector, which has been called as indirect impact. This thesis provides a comprehensive examination of the scalar sector's role in GUTs, establishing connections between UV-complete models and observable phenomena.
Sezen Sekmen, Gokhan Unel, Harrison B. Prosper
et al.
Data analysis at the LHC has a very steep learning curve, which erects a formidable barrier between data and anyone who wishes to analyze data, either to study an idea or to simply understand how data analysis is performed. To make analysis more accessible, we designed the so-called Analysis Description Language (ADL), a domain specific language capable of describing the contents of an LHC analysis in a standard and unambiguous way, independent of any computing frameworks. ADL has an English-like highly human-readable syntax and directly employs concepts relevant to HEP. Therefore it eliminates the need to learn complex analysis frameworks written based on general purpose languages such as C++ or Python, and shifts the focus directly to physics. Analyses written in ADL can be run on data using a runtime interpreter called CutLang, without the necessity of programming. ADL and CutLang are designed for use by anyone with an interest in, and/or knowledge of LHC physics, ranging from experimentalists and phenomenologists to non-professional enthusiasts. ADL/CutLang are originally designed for research, but are also equally intended for education and public use. This approach has already been employed to train undergraduate students with no programming experience in LHC analysis in two dedicated schools in Turkey and Vietnam, and is being adapted for use with LHC Open Data. Moreover, work is in progress towards piloting an educational module in particle physics data analysis for high school students and teachers. Here, we introduce ADL and CutLang and present the educational activities based on these practical tools.
Obtaining the values of the coupling constants of the low energy effective theory corresponding to QCD, compatible with experimental data, even in the (vector) mesonic sector from (the ${\cal M}$-theory uplift of) a UV-complete string theory dual, has thus far been missing in the literature. We take the first step in this direction by obtaining the values of the coupling constants of the ${\cal O}(p^4)$ $χ$PT Lagrangian in the chiral limit involving the NGBs and $ρ$ meson (and its flavor partners) from the ${\cal M}$-theory /type IIA dual of large-$N$ thermal QCD, inclusive of the ${\cal O}(R^4)$ corrections. We observe that ensuring compatibility with phenomenological/lattice results (the values ) as given in arXiv:1510.01634[hep-ph], requires a relationship relating the ${\cal O}(R^4)$ corrections and large-$N$ suppression. In other words, QCD demands that the higher derivative corrections and the large-$N$ suppressed corrections in its M/string theory dual are related. As a bonus, we explicitly show that the ${\cal O}(R^4)$ corrections in the UV to the ${\cal M}$-theory uplift of the type IIB dual of large-$N$ thermal QCD, can be consistently set to be vanishingly small.
Recently we have proved NRQCD color octet factorization of S-wave and P-wave heavy quarkonia production at all orders in coupling constant in QCD in vacuum at high energy colliders in Eur. Phys. J. C76 (2016) 448 and in arXiv:1807.04722 [hep-ph] respectively. In this paper we extend this to prove NRQCD color octet factorization of P-wave heavy quarkonium production in non-equilibrium QCD at RHIC and LHC at all orders in coupling constant. This proof is necessary to study the quark-gluon plasma at RHIC and LHC.
A. N. Ivanov, R. Höllwieser, N. I. Troitskaya
et al.
As we have pointed out in (arXiv:1806.10107 [hep-ph]), the existence of neutron dark matter decay modes "n -> chi + anything", where "chi" is a dark matter fermion, for the solution of the neutron lifetime problem changes priorities and demands to describe the neutron lifetime "tau_n = 888.0(2.0)s", measured in beam experiments and defined by the decay modes "n -> p + anything", in the Standard Model (SM). The latter requires the axial coupling constant "lambda" to be equal to "lambda = - 1.2690" (arXiv:1806.10107 [hep-ph]). Since such an axial coupling constant is excluded by experimental data reported by the PERKEO II and UCNA Collaborations, the neutron lifetime "tau_n = 888.0(2.0)s" can be explained only by virtue of interactions beyond the SM, namely, by the Fierz interference term of order "b ~ - 10^{-2}" dependent on scalar and tensor coupling constants. We give a complete analysis of all correlation coefficients of the neutron beta decays with polarized neutron, taking into account the contributions of scalar and tensor interactions beyond the SM with the Fierz interference term "b ~ - 10^{-2}". We show that the obtained results agree well with the contemporary experimental data that does not prevent the neutron with the rate of the decay modes "n -> p + anything", measured in beam experiments, to have dark matter decay modes "n -> chi + anything".