MATTER FIELDS ON A TWO-SHEETED SPACE-TIME

2005 ◽  
Vol 20 (06) ◽  
pp. 1346-1352
Author(s):  
KAMESHWAR C. WALI

As a prelude to the standard model in curved space time, we present a model of a left- and a right- chiral field living on a two-sheeted space-time. The resulting action functionals include novel interactions due to extended gravity.

2019 ◽  
Author(s):  
Adib Rifqi Setiawan

Put simply, Lisa Randall’s job is to figure out how the universe works, and what it’s made of. Her contributions to theoretical particle physics include two models of space-time that bear her name. The first Randall–Sundrum model addressed a problem with the Standard Model of the universe, and the second concerned the possibility of a warped additional dimension of space. In this work, we caught up with Randall to talk about why she chose a career in physics, where she finds inspiration, and what advice she’d offer budding physicists. This article has been edited for clarity. My favourite quote in this interview is, “Figure out what you enjoy, what your talents are, and what you’re most curious to learn about.” If you insterest in her work, you can contact her on Twitter @lirarandall.


2019 ◽  
Author(s):  
Adib Rifqi Setiawan

Put simply, Lisa Randall’s job is to figure out how the universe works, and what it’s made of. Her contributions to theoretical particle physics include two models of space-time that bear her name. The first Randall–Sundrum model addressed a problem with the Standard Model of the universe, and the second concerned the possibility of a warped additional dimension of space. In this work, we caught up with Randall to talk about why she chose a career in physics, where she finds inspiration, and what advice she’d offer budding physicists. This article has been edited for clarity. My favourite quote in this interview is, “Figure out what you enjoy, what your talents are, and what you’re most curious to learn about.” If you insterest in her work, you can contact her on Twitter @lirarandall.


2020 ◽  
Vol 29 (11) ◽  
pp. 2041012
Author(s):  
Pedro D. Alvarez ◽  
Mauricio Valenzuela ◽  
Jorge Zanelli

General Relativity (GR) and the Standard Model (SM) of particle physics are two enormously successful frameworks for our understanding the fundamental laws of nature. However, these theoretical schemes are widely disconnected, logically independent and unrelated in scope. Yet, GR and SM at some point must intersect, producing claims about phenomena that should be reconciled. Be it as it may, both schemes share a common basic ground: symmetry under local Lorentz transformations. Here, we will focus on the consequences of assuming this feature from the beginning to combine geometry, matter fields and gauge interactions. We give a rough description of how this could be instrumental for the construction of a unified scheme of gravitation and particle physics.


1998 ◽  
Vol 13 (06) ◽  
pp. 465-478 ◽  
Author(s):  
RECAI ERDEM

We find that the local character of field theory requires the parity degree of freedom of the fields to be considered as an additional discrete fifth dimension which is an artifact emerging due to the local description of space–time. Higgs field can be interpreted as the gauge field corresponding to this discrete dimension. Hence the noncommutative geometric derivation of the standard model follows as a manifestation of the local description of the usual space–time.


2015 ◽  
Vol 93 (9) ◽  
pp. 988-994 ◽  
Author(s):  
Pietro Donà ◽  
Astrid Eichhorn ◽  
Roberto Percacci

We discuss the compatibility of quantum gravity with dynamical matter degrees of freedom. Specifically, we present bounds we obtained in Donà et al. (Phys. Rev. D, 89, 084035 (2014) doi:10.1103/PhysRevD.89.084035 ) on the allowed number and type of matter fields within asymptotically safe quantum gravity. As a novel result, we show bounds on the allowed number of spin-3/2 (Rarita–Schwinger) fields (e.g., the gravitino). These bounds, obtained within truncated renormalization group flows, indicate the compatibility of asymptotic safety with the matter fields of the standard model. Further, they suggest that extensions of the matter content of the standard model are severely restricted in asymptotic safety. This means that searches for new particles at colliders could provide experimental tests for this particular approach to quantum gravity.


2021 ◽  
Author(s):  
Tejinder P. Singh

Abstract We have recently proposed a pre-quantum, pre-space-time theory as a matrix-valued La-grangian dynamics on an octonionic space-time. This pre-theory offers the prospect of unifying the internal symmetries of the standard model with gravity. It can also predict the values of free parameters of the standard model, because these parameters arising in the Lagrangian are related to the algebra of the octonions which define the underlying non-commutative space-time on which the dynamical degrees of freedom evolve. These free parameters are related to the algebra J3 (O) [exceptional Jordan algebra] which in turn is related to the three fermion generations. The exceptional Jordan algebra [also known as the Albert algebra] is the finite dimensional algebra of 3x3 Hermitean matrices with octonionic entries. Its automorphism group is the exceptional Lie group F4. These matrices admit a cubic characteristic equation whose eigenvalues are real and depend on the invariant trace, determinant, and an inner product made from the Jordan matrix. Also, there is some evidence in the literature that the groups F4 and E6 could play a role in the unification of the standard model symmetries, including the Lorentz symmetry. The octonion algebra is known to correctly yield the electric charge values (0, 1/3, 2/3, 1) for standard model fermions, via the eigenvalues of a U (1) number operator, identified with U (1)em. In the present article, we use the same octonionic representation of the fermions to compute the eigenvalues of the characteristic equation of the Albert algebra, and compare the resulting eigenvalues with the known mass ratios for quarks and leptons. We find that the ratios of the eigenvalues correctly reproduce the [square root of the] known mass ratios for quarks and charged leptons. We also propose a diagrammatic representation of the standard model bosons, Higgs and three fermion generations, in terms of the octonions, exhibiting an F4 and E6 symmetry. In conjunction with the trace dynamics Lagrangian, the Jordan eigenvalues also provide a first principles theoretical derivation of the low energy value of the fine structure constant, yielding the value 1/137.04006. The Karolyhazy correction to this value gives an exact match with the measured value of the constant, after assuming a specific value for the electro-weak symmetry breaking energy scale.


Author(s):  
Tejinder Pal Singh

We have recently proposed a pre-quantum, pre-space-time theory as a matrix-valued Lagrangian dynamics on an octonionic space-time. This pre-theory offers the prospect of unifying the internal symmetries of the standard model with gravity. It can also predict the values of free parameters of the standard model, because these parameters arising in the Lagrangian are related to the algebra of the octonions which define the underlying non-commutative space-time on which the dynamical degrees of freedom evolve. These free parameters are related to the algebra $J_3(\mathbb O)$ [exceptional Jordan algebra] which in turn is related to the three fermion generations. The exceptional Jordan algebra [also known as the Albert algebra] is the finite dimensional algebra of 3x3 Hermitean matrices with octonionic entries. Its automorphism group is the exceptional Lie group $F_4$. These matrices admit a cubic characteristic equation whose eigenvalues are real and depend on the invariant trace, determinant, and an inner product made from the Jordan matrix. Also, there is some evidence in the literature that the group $F_4$ could play a role in the unification of the standard model symmetries, including the Lorentz symmetry. The octonion algebra is known to correctly yield the electric charge values (0, 1/3, 2/3, 1) for standard model fermions, via the eigenvalues of a $U(1)$ number operator, identified with $U(1)_{em}$. In the present article, we use the same octonionic representation of the fermions to compute the eigenvalues of the characteristic equation of the Albert algebra, and compare the resulting eigenvalues with the known mass ratios for quarks and leptons. We find that the ratios of the eigenvalues correctly reproduce the [square root of the] known mass ratios for up, charm and top quark. We also propose a diagrammatic representation of the standard model bosons, Higgs and three fermion generations, in terms of the octonions, exhibiting an $F_4$ symmetry. We motivate from our Lagrangian as to why the eigenvalues computed in this work could bear a relation with mass ratios of quarks and leptons. In conjunction with the trace dynamics Lagrangian, the Jordan eigenvalues also provide a first principles theoretical derivation of the low energy value of the fine structure constant, yielding the value $1/137.04006$. The Karolyhazy correction to this value gives an exact match with the measured value of the constant, after assuming a specific value for the electro-weak symmetry breaking energy scale.


2013 ◽  
Vol 28 (11) ◽  
pp. 1330007 ◽  
Author(s):  
A. S. CORNELL ◽  
ALDO DEANDREA ◽  
LU-XIN LIU ◽  
AHMAD TARHINI

We review the renormalization group evolution of quark and lepton masses, mixing angles and phases both in the UED extension of the Standard Model (SM) and of the Minimal Supersymmetric Standard Model (MSSM). We consider two typical scenarios: all matter fields propagating in the bulk and matter fields constrained to the brane. The resulting renormalization group evolution equations in these scenarios are compared with the existing results in the literature, together with their implications.


2002 ◽  
Vol 23 (2) ◽  
pp. 363-376 ◽  
Author(s):  
X. Calmet ◽  
B. Jurčo ◽  
P. Schupp ◽  
J. Wess ◽  
M. Wohlgenannt

2019 ◽  
Vol 97 (10) ◽  
pp. 1096-1103 ◽  
Author(s):  
Khiem Hong Phan

In this paper, we derive hypergeometric function representation of one-loop contributing to Higgs decay to two photons in the standard model and its extensions. The calculations are performed at general space–time dimension d. For the first time, analytic results are published for form factors that are valid in arbitrary space–time dimension. Moreover, we confirm against analytic results in previous computations that have been available in space–time dimension d = 4 – 2ϵ at ϵ0 expansions.


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