THERMAL MASS SHIFTS IN OPEN SUPERSTRING MODELS

1990 ◽  
Vol 05 (01) ◽  
pp. 175-185 ◽  
Author(s):  
L. CLAVELLI ◽  
P. ELMFORS ◽  
B. HARMS ◽  
B.-S. SKAGERSTAM ◽  
A. STERN
Keyword(s):  
Space Time ◽  
Mass Shift ◽  
Tree Level ◽  
Thermal Mass ◽  
Type I ◽  
Zero Temperature ◽  
Loop Correction ◽  
Level Densities ◽  
Scalar Mesons ◽  
Mass Shifts

We investigate some thermodynamical properties of an open type I superstring model in six space-time dimensions. The model is free of tachyons at the tree level but acquires a tachyonic one-loop mass shift at zero-temperature. Even though the space-time supersymmetry is spontaneously broken, the asymptotic form of the fermionic and bosonic level densities are the same, i.e. there is a unique Hagedorn temperature TH. As expected, TH is a limiting temperature, i.e. the energy density of the string gas diverges at T=TH. The finite temperature one-loop correction to the mass of the scalar mesons, which are massless at three level, is calculated and is found to be finite for all temperatures. It is found that thermal corrections do not stabilize the zero-temperature one-loop tachyonic mass shift of the model.

scholarly journals CLASSICAL AND QUANTUM STRINGS IN PLANE WAVES, SHOCK WAVES AND SPACE–TIME SINGULARITIES: SYNTHESIS AND NEW RESULTS

2003 ◽  
Vol 18 (26) ◽  
pp. 4797-4809 ◽  
Author(s):  
NORMA G. SANCHEZ
Keyword(s):  
Shock Waves ◽  
Plane Waves ◽  
Momentum Tensor ◽  
Space Time ◽  
Tree Level ◽  
Time Singularities ◽  
String Spectrum ◽  
Key Issues ◽  
Real Mass ◽  
Singular Wave

Key issues and essential features of classical and quantum strings in gravitational plane waves, shock waves and space–time singularities are synthetically understood. This includes the string mass and mode number excitations, energy–momentum tensor, scattering amplitudes, vacuum polarization and wave-string polarization effect. The role of the real pole singularities characteristic of the tree level string spectrum (real mass resonances) and that of the space–time singularities is clearly exhibited. This throws light on the issue of singularities in string theory which can be thus classified and fully physically characterized in two different sets: strong singularities (poles of order ≥ 2, and black holes) where the string motion is collective and nonoscillating in time, outgoing states and scattering sector do not appear, the string does not cross the singularities; and weak singularities (poles of order < 2, (Dirac δ belongs to this class) and conic/orbifold singularities) where the whole string motion is oscillatory in time, outgoing and scattering states exist, and the string crosses the singularities. Common features of strings in singular wave backgrounds and in inflationary backgrounds are explicitly exhibited. The string dynamics and the scattering/excitation through the singularities (whatever their kind: strong or weak) is fully physically consistent and meaningful.

scholarly journals PROBING FOAMY SPACE–TIME WITH VARIATIONAL METHODS

1999 ◽  
Vol 14 (18) ◽  
pp. 2905-2920 ◽  
Author(s):  
REMO GARATTINI
Keyword(s):  
Black Hole ◽  
Variational Methods ◽  
Momentum Space ◽  
Flat Space ◽  
Casimir Energy ◽  
Space Time ◽  
Pair Creation ◽  
Variational Procedure ◽  
Loop Correction ◽  
Quasilocal Energy

A one-loop correction of the quasilocal energy in the Schwarzschild background, with flat space as a reference metric, is performed by means of a variational procedure in the Hamiltonian framework. We examine the graviton sector in momentum space, in the lowest possible state. An application to the black hole pair creation via the Casimir energy is presented. Implications on the foamlike scenario are discussed.

Fermion masses and mixings in a 3-3-1 model withQ4symmetry

2019 ◽  
Vol 34 (25) ◽  
pp. 1950198
Author(s):  
V. V. Vien ◽  
D. P. Khoi
Keyword(s):  
Neutrino Mass ◽  
Mass Parameter ◽  
Majorana Neutrino ◽  
Tree Level ◽  
Type I ◽  
Inverted Hierarchy ◽  
Quark Masses ◽  
Fermion Masses ◽  
Majorana Neutrino Mass ◽  
Good Agreement

We construct a renormalizable [Formula: see text] model with [Formula: see text] symmetry accommodating the observed pattern of fermion masses and mixings with Dirac CP violation phase. The smallness of the active neutrino masses arises from a combination of type I and type II seesaw mechanisms. Both normal and inverted neutrino mass ordering are viable in our model in which the obtained physical observables of the lepton sector are well consistent with the global fit of neutrino oscillation data [P. F. de Salas et al., Phys. Lett. B 782, 633 (2018)] while the CKM matrix is unity at tree level and the quark masses are in good agreement with the experimental data [Particle Data Group (M. Tanabashi et al.), Phys. Rev. D 98, 030001 (2018)]. Furthermore, the model also predicts an effective Majorana neutrino mass parameter of [Formula: see text] eV for normal hierarchy and [Formula: see text] for inverted hierarchy which are consistent with the constraints given in [P. F. de Salas et al., Phys. Lett. B 782, 633 (2018)].

scholarly journals Two-flavor chiral perturbation theory at nonzero isospin: pion condensation at zero temperature

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Prabal Adhikari ◽  
Jens O. Andersen ◽  
Patrick Kneschke
Keyword(s):  
Perturbation Theory ◽  
Equation Of State ◽  
Condensed Phase ◽  
Chiral Perturbation Theory ◽  
Chemical Potential ◽  
Tree Level ◽  
Zero Temperature ◽  
Leading Order ◽  
Chiral Perturbation ◽  
Pion Condensation

Abstract In this paper, we calculate the equation of state of two-flavor finite isospin chiral perturbation theory at next-to-leading order in the pion-condensed phase at zero temperature. We show that the transition from the vacuum phase to a Bose-condensed phase is of second order. While the tree-level result has been known for some time, surprisingly quantum effects have not yet been incorporated into the equation of state.  We find that the corrections to the quantities we compute, namely the isospin density, pressure, and equation of state, increase with increasing isospin chemical potential. We compare our results to recent lattice simulations of 2 + 1 flavor QCD with physical quark masses. The agreement with the lattice results is generally good and improves somewhat as we go from leading order to next-to-leading order in $$\chi $$χPT.

CONSTRUCTING THE SUPERSTRING SPACE-TIME SUSY ALGEBRA IN THE LIGHT-CONE GAUGE

1988 ◽  
Vol 03 (12) ◽  
pp. 2855-2893 ◽  
Author(s):  
A. RESTUCCIA ◽  
J.G. TAYLOR
Keyword(s):  
Light Cone ◽  
Explicit Construction ◽  
Space Time ◽  
Substantial Part ◽  
Type I ◽  
Type Ii ◽  
Contact Interactions ◽  
Regularization Scheme ◽  
Light Cone Gauge

Closure of the [10] SUSY algebra is attempted for heterotic and type II superstrings by explicit construction of the quartic supersymmetry and Hamiltonian generators. These are shown to possess only contact interactions. Other related nonlinearly realized generators are also constructed at the quartic level, and a substantial part of the [10]-SUSY algebra shown to close with only these generators, for any regularization scheme for the heterotic, and by using phase integration for the type II. Type I superstrings are also considered.

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