Probing signs of new physics at low energies: the neutrino case

Elpe, Altuğ
Neutrinos have a special place in particle physics. They are spin-1/2, electrically neutral, nearly massless, and very weakly interacting particles. Properties of weak interactions can be conveniently studied through neutrinos. They are assumed to be sensitive to new physics effects. Moreover, searching for new physics at low en- ergies has its motivations based on the null results about new physics at high ener- gies coming out of Hadron Colliders’ data. One of the favorite signs of new physics at low energies would be the so-called dark sector, which would show some sizable effects in neutrino scattering experiments. This thesis analyzes Abelian dark sec- tor scenarios embedded into the two-Higgs doublet models through the Coherent Elastic Neutrino-Nucleus Scattering experiment, which was first measured by the COHERENT Collaboration in 2017. The theoretical framework assumes that there is a U(1) gauge group in the dark sector with a non-zero kinetic mixing with the hypercharge field. Moreover, the scalar sector of the Standard Model is extended with a second doublet which, under certain assumptions, makes mass mixing be- tween the dark gauge field and neutral electroweak fields possible. The COHER- ENT data for the CsI and liquid argon (LAr) targets are used to constraint the multi- vdimensional parameter space, spanned by the dark gauge coupling, kinetic mixing parameter, and the dark photon mass, for a total of seven different representative scenarios, which are also compared and contrasted among each other to find out about the most sensitive one to the data.


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The dependence of the rate of proton-proton interactions on the centre-of-mass collision energy, root s, is of fundamental importance for both hadron collider physics and particle astrophysics. The dependence cannot yet be calculated from first principles; therefore, experimental measurements are needed. Here we present the first measurement of the inelastic proton-proton interaction cross-section at a centre-of-mass energy, root s, of 7 TeV using the ATLAS detector at the Large Hadron Collider. Events are ...
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Citation Formats
A. Elpe, “Probing signs of new physics at low energies: the neutrino case,” Ph.D. - Doctoral Program, Middle East Technical University, 2023.