عنوان

MeV ölçeğinde ayarlı ve geometrik vektör alanlar

Number

TLpq2522819073

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

MeV ölçeğinde ayarlı ve geometrik vektör alanlar

General Material Designation

[Thesis]

First Statement of Responsibility

Puliçe, Beyhan

Subsequent Statement of Responsibility

Demir, Durmuş Ali

Name of Publisher, Distributor, etc.

Izmir Institute of Technology (Turkey)

Date of Publication, Distribution, etc.

2020

Specific Material Designation and Extent of Item

57

Dissertation or thesis details and type of degree

Ph.D.

Body granting the degree

Izmir Institute of Technology (Turkey)

Text preceding or following the note

2020

Text of Note

In this thesis, we have studied gauged and geometric vector fields at the MeV scale in two main parts. The basic framework of these two parts are given briefly as follows. In the first part (Chapter 2), we have built a family-nonuniversal U(1) model populated by an MeV-scale sector with a minimal new field content which explains the recent anomalous beryllium decays. Excited beryllium has been observed to decay into electron-positron pairs with a 6.8 σ anomaly. The process is properly explained by a 17 MeV proto-phobic vector boson. In this thesis, we consider a family-nonuniversal U(1)' that is populated by the U(1)' gauge boson Z' and a scalar field S. The kinetic mixing of Z' with the hypercharge gauge boson, as we show by a detailed analysis, generates the observed beryllium anomaly. We show that beryllium anomaly can be explained by an MeV-scale sector with a minimal new field content. In the second part (Chapter 3), we have shown how a light vector particle can arise from metric-affine gravity and how this particle fits the current data and constraints on the dark matter. We show that, metric-affine gravity , which involves metric tensor and affine connection as two independent fields, dynamically reduces, in its minimal form, to the usual gravity plus a massive vector field. The vector Yμ is neutral and long-living when its mass range lies in the range 9.4 MeV < MY < 28.4 MeV. Its scattering cross section from nucleons, which is some 60 orders of magnitude below the current bounds, is too small to facilitate direct detection of the dark matter. This property provides an explanation for whys and hows of dark matter searches. We show that due to its geometrical origin the Yμ couples only to fermions. This very feature of the Yμ makes it fundamentally different than all the other vector dark matter candidates in the literature. The geometrical dark matter we present is minimal and self-consistent not only theoretically but also astrophysically in that its feebly interacting nature is all that is needed for its longevity.

Dark matter

Physics

Quantum field theory

Demir, Durmuş Ali

Puliçe, Beyhan

Electronic name

p

[Thesis]

276903

a

Y