Some Aspects of Chirality: fermion masses and chiral pforms
Research output: Thesis › Doctoral Thesis (compilation)
Abstract
This thesis deals with different types of chiral fields.
The properties of fermion masses are investigated from different poits of view, both within the Standard Model and in extensions of the model. It is shown how mass matrix invariants are used to define the measurables of the quark mixing matrix as invariant functions of the mass matrices.
One model is presented where the family pattern is suggested to originate from a kind of mass scaling. A Lagrangian density is defined for an entire charge sector, such that the existence of a Dirac field with a certain mass implies the existence of other Dirac fields, where the corresponding quanta have masses which are obtained from the initial mass by a discrete scale transformation. This suggests a certain type of democratic fermion mass matrices.
Also extensions of the minimal Standard Model are investigated, obtained by including righthanded neutrions in the model. The Standard Model extended by two righthanded neutrinos gives rise to a mass spectrum with two massive and three massless (at tree level) neutrinos. No assumptions such as the seesaw assumption of a large mass scale are necessary, provided the neutrino mass matrix assumes a certain form. The phenomenological consequences of this model are discussed. The neutrino mass matrix in such a scheme has what is defined as a democratic texture. The democratic family mixing matrix, with only unit entries, is found to act as a projection matrix in the sense that multiplying any 3x3 matrix with the democratic matrix is the same as multiplying an appropriate diagonal 3x3 matrix with the democratic matrix. Neutrino mass matrices with a democratic texture are studied for the cases with two and three righthanded neutrinos, respectively.
The chiral fields that we find in the Standard Model have certain similarities with selfdual fields. Among other things, both chiral and selfdual fields suffer species doubling on the lattice. Chiral pforms are selfdual fields that appear in twiceodd dimensions. Chiral pforms violet manifest covariance, in the same sense that manifest covariance is violated by noncovariant gauges in electrodynamics. It is shown that a covariant action can nevertheless be formulated for chiral pforms, by introducing an infinite set of gauge fields in a carefully controlled way.
The properties of fermion masses are investigated from different poits of view, both within the Standard Model and in extensions of the model. It is shown how mass matrix invariants are used to define the measurables of the quark mixing matrix as invariant functions of the mass matrices.
One model is presented where the family pattern is suggested to originate from a kind of mass scaling. A Lagrangian density is defined for an entire charge sector, such that the existence of a Dirac field with a certain mass implies the existence of other Dirac fields, where the corresponding quanta have masses which are obtained from the initial mass by a discrete scale transformation. This suggests a certain type of democratic fermion mass matrices.
Also extensions of the minimal Standard Model are investigated, obtained by including righthanded neutrions in the model. The Standard Model extended by two righthanded neutrinos gives rise to a mass spectrum with two massive and three massless (at tree level) neutrinos. No assumptions such as the seesaw assumption of a large mass scale are necessary, provided the neutrino mass matrix assumes a certain form. The phenomenological consequences of this model are discussed. The neutrino mass matrix in such a scheme has what is defined as a democratic texture. The democratic family mixing matrix, with only unit entries, is found to act as a projection matrix in the sense that multiplying any 3x3 matrix with the democratic matrix is the same as multiplying an appropriate diagonal 3x3 matrix with the democratic matrix. Neutrino mass matrices with a democratic texture are studied for the cases with two and three righthanded neutrinos, respectively.
The chiral fields that we find in the Standard Model have certain similarities with selfdual fields. Among other things, both chiral and selfdual fields suffer species doubling on the lattice. Chiral pforms are selfdual fields that appear in twiceodd dimensions. Chiral pforms violet manifest covariance, in the same sense that manifest covariance is violated by noncovariant gauges in electrodynamics. It is shown that a covariant action can nevertheless be formulated for chiral pforms, by introducing an infinite set of gauge fields in a carefully controlled way.
Details
Authors  

Organisations  
Research areas and keywords  Subject classification (UKÄ) – MANDATORY
Keywords

Original language  English 

Qualification  Doctor 
Awarding Institution  
Supervisors/Assistant supervisor 

Award date  1997 May 30 
Publisher 

Print ISBNs  9162825771 
Publication status  Published  1997 
Publication category  Research 
Bibliographic note
Defence details
Date: 19970530
Time: 13:15
Place: May 30 1997 at 13.15, in Kårhusets Hörsal LTH
External reviewer(s)
Name: Osland, Per
Title: [unknown]
Affiliation: Bergen University

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Mathematical Physics (Faculty of Technology) (011040002)