Thermal mass shifts in a four-dimensional open-string model

1990 ◽  
Vol 42 (6) ◽  
pp. 2153-2155 ◽  
Author(s):  
L. Clavelli ◽  
B. Harms
Keyword(s):  
String Model ◽  
Open String ◽  
Thermal Mass ◽  
Mass Shifts

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 GAUGE SYMMETRY BREAKING IN ORBIFOLD MODEL BUILDING

2006 ◽  
Vol 21 (30) ◽  
pp. 2251-2267 ◽  
Author(s):  
MICHELE TRAPLETTI
Keyword(s):  
Gauge Symmetry ◽  
Symmetry Breaking ◽  
Extra Dimensions ◽  
Model Building ◽  
String Model ◽  
Open String ◽  
Internal Space ◽  
Four Dimensions ◽  
String Compactifications ◽  
Breaking Mechanism

We review the gauge symmetry breaking mechanism due to orbifold projections in orbifold model building. We explicitly show the existence of a scale of breaking if such a symmetry breaking is due to freely-acting orbifold operators only, i.e. in case the breaking is realized nonlocally in the internal space. We show that such a scale is related to the compactification moduli only, and that there are no extra continuous parameters, at least in semirealistic models with [Formula: see text] SUSY in four dimensions. In this sense, the mechanism is peculiarly different from the standard Higgs (or Hosotani) symmetry breaking mechanism. We show that the mechanism also differs from that present in standard orbifold models where, even in the presence of discrete Wilson lines, a scale of breaking is generically missing, since the breaking is localized in specific points in the internal space. We review a set of background geometries where the described nonlocal breaking is realized, both in the case of two and six extra dimensions. In the latter case, relevant in string model building, we consider both heterotic and open string compactifications.

Open string model building

1989 ◽  
Vol 318 (1) ◽  
pp. 239-280 ◽  
Author(s):  
Nobuyuki Ishibashi ◽  
Tetsuya Onogi
Keyword(s):  
Model Building ◽  
String Model ◽  
Open String

scholarly journals Open string instantons and superpotentials

2000 ◽  
Vol 62 (2) ◽  
Author(s):  
Shamit Kachru ◽  
Sheldon Katz ◽  
Albion Lawrence ◽  
John McGreevy
Keyword(s):  
Open String
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