Results 1  10
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182
Strong dynamics and electroweak symmetry breaking
, 2002
"... The breaking of electroweak √ symmetry, and origin of the associated “weak scale, ” vweak = 1 / 2 √ 2GF = 175 GeV, may be due to a new strong interaction. Theoretical developments over the past decade have led to viable models and mechanisms that are consistent with current experimental data. Many o ..."
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Cited by 81 (0 self)
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The breaking of electroweak √ symmetry, and origin of the associated “weak scale, ” vweak = 1 / 2 √ 2GF = 175 GeV, may be due to a new strong interaction. Theoretical developments over the past decade have led to viable models and mechanisms that are consistent with current experimental data. Many of these schemes feature a priveleged role for the top quark, and third generation, and are natural in the context of theories of extra space dimensions at the weak scale. We review various models and their phenomenological implications which will be subject to definitive tests in future collider runs at the Tevatron, and the LHC, and future linear e + e − colliders, as well as sensitive
Spectra of selfadjoint extensions and applications to solvable Schrödinger operators
, 2007
"... ..."
Quantized Gauge Theory on the Fuzzy Sphere as Random
 Matrix Model, Nucl. Phys. B679
, 2004
"... Gauge theories provide the best known description of the fundamental forces in nature. At very short distances however, physics is not known, and it seems unlikely that spacetime is a perfect continuum down to arbitrarily small scales. Indeed, physicists have started to learn in recent years how to ..."
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Cited by 59 (16 self)
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Gauge theories provide the best known description of the fundamental forces in nature. At very short distances however, physics is not known, and it seems unlikely that spacetime is a perfect continuum down to arbitrarily small scales. Indeed, physicists have started to learn in recent years how to formulate field
Renormalization theory and ultraviolet stability for scalar fields via renormalization group methods
 Reviews of Modern Physics
, 1985
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The Cosmological Constant and the String Landscape
"... Theories of the cosmological constant fall into two classes, those in which the vacuum energy is fixed by the fundamental theory and those in which it is adjustable in some way. For each class we discuss key challenges. The string theory landscape is an example of an adjustment mechanism. We discuss ..."
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Cited by 49 (1 self)
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Theories of the cosmological constant fall into two classes, those in which the vacuum energy is fixed by the fundamental theory and those in which it is adjustable in some way. For each class we discuss key challenges. The string theory landscape is an example of an adjustment mechanism. We discuss the status of this idea, and future directions. Rapporteur talk at the 23rd Solvay Conference in Physics, December, 2005. 1 The cosmological constant I would like to start by drawing a parallel to an earlier meeting — not a Solvay conference, but the 1947 Shelter Island conference. In both cases a constant of nature was at the center of discussions. In each case theory gave an unreasonably large or infinite value for the constant, which had therefore been assumed to vanish for reasons not yet understood, but in each case experiment or observation had recently found a nonzero value. At Shelter
The littlest Higgs
 JHEP
, 2002
"... Abstract: We present an economical theory of natural electroweak symmetry breaking, generalizing an approach based on deconstruction. This theory is the smallest extension of the Standard Model to date that stabilizes the electroweak scale with a naturally light Higgs and weakly coupled new physics ..."
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Cited by 39 (4 self)
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Abstract: We present an economical theory of natural electroweak symmetry breaking, generalizing an approach based on deconstruction. This theory is the smallest extension of the Standard Model to date that stabilizes the electroweak scale with a naturally light Higgs and weakly coupled new physics at TeV energies. The Higgs is one of a set of pseudo Goldstone bosons in an SU(5)/SO(5) nonlinear sigma model. The symmetry breaking scale f is around a TeV, with the cutoff Λ< ∼ 4πf ∼ 10 TeV. A single electroweak doublet, the “little Higgs”, is automatically much lighter than the other pseudo Goldstone bosons. The quartic selfcoupling for the little Higgs is generated by the gauge and Yukawa interactions with a natural size O(g 2,λ 2 t), while the top Yukawa coupling generates a negative mass squared triggering electroweak symmetry breaking. Beneath the TeV scale the effective theory is simply the minimal Standard Model. The new particle content at TeV energies consists of one set of spin one bosons with the same quantum numbers as the electroweak gauge bosons, an electroweak singlet quark with charge 2/3, and an electroweak triplet scalar. One loop quadratically divergent corrections to the Higgs mass are cancelled by interactions with these additional particles
Magnetic bion condensation: A new mechanism of confinement and mass gap in four dimensions, arXiv:0709.3269 [hepth
 26 A. Armoni, JHEP
, 2007
"... Abstract: In recent work, we derived the long distance confining dynamics of certain QCDlike gauge theories formulated on small S 1 × R 3 based on symmetries, an index theorem and abelian duality. Here, we give the microscopic derivation. The solution reveals a new mechanism of confinement in QCD(ad ..."
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Cited by 35 (8 self)
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Abstract: In recent work, we derived the long distance confining dynamics of certain QCDlike gauge theories formulated on small S 1 × R 3 based on symmetries, an index theorem and abelian duality. Here, we give the microscopic derivation. The solution reveals a new mechanism of confinement in QCD(adj) in the regime where we have control over both perturbative and nonperturbative aspects. In particular, consider SU(2) QCD(adj) theory with 1 ≤ nf ≤ 4 Majorana fermions, a theory which undergoes gauge symmetry breaking at small S 1. If the magnetic charge of the BPS monopole is normalized to unity, we show that confinement occurs due to condensation of objects with magnetic charge 2, not 1. Due to index theorems, we know that such an object cannot be a two identical monopole configuration. Its net topological charge must vanish, and hence it must be topologically indistinguishable from the perturbative vacuum. We construct such objects, the magnetically charged, topologically null molecules of a BPS monopole and KK antimonopole, which we refer as magnetic bions. An immediate puzzle with this proposal is the apparent Coulomb repulsion between BPSKK pair. An attraction which overcomes the Coulomb repulsion between the two is induced by 2nffermion exchange. Bion condensation is also the mechanism of confinement in N = 1 SYM on the same fourmanifold. The SU(N) generalization hints a possible hidden integrability behind nonsupersymmetric QCD of affine Toda type, and allows us to analytically compute the string tensions and thicknesses. We currently do not know the extension to R 4.
MetaStable Supersymmetry Breaking in a Cooling Universe,” hepth/0611018
"... Preprint typeset in JHEP style HYPER VERSION hepth/0611018 ..."
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Preprint typeset in JHEP style HYPER VERSION hepth/0611018
Perturbative gauge theory and closed string tachyons
 JHEP
, 2005
"... We find an interesting connection between perturbative large N gauge theory and closed superstrings. The gauge theory in question is found on N D3branes placed at the tip of the cone R 6 /Γ. In our previous work we showed that, when the orbifold group Γ breaks all supersymmetry, then typically the ..."
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We find an interesting connection between perturbative large N gauge theory and closed superstrings. The gauge theory in question is found on N D3branes placed at the tip of the cone R 6 /Γ. In our previous work we showed that, when the orbifold group Γ breaks all supersymmetry, then typically the gauge theory is not conformal because of doubletrace couplings whose oneloop beta functions do not possess real zeros. In this paper we observe a precise correspondence between the instabilities caused by the flow of these doubletrace couplings and the presence of tachyons in the twisted sectors of type IIB theory on orbifolds R 3,1 × R 6 /Γ. For each twisted sectors that does not contain tachyons, we show that the corresponding doubletrace coupling flows to a fixed point and does not cause an instability. However, whenever a twisted sector is tachyonic, we find that the corresponding oneloop beta function does not have a real zero, hence an instability is likely to exist in the gauge theory. We demonstrate explicitly the onetoone correspondence between the regions of stability/instability in the space of charges under Γ that arise in the perturbative gauge theory and in the free string theory. Possible implications of this remarkably simple gauge/string correspondence are discussed. 2005 1
Closed Strings as Imaginary Dbranes
, 2004
"... Sen has recently drawn attention to an exact timedependent Boundary Conformal Field Theory with the spacetime interpretation of brane creation and annihilation. An interesting limit of this BCFT is formally equivalent to an array of Dbranes located in imaginary time. This raises the question: wha ..."
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Cited by 26 (1 self)
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Sen has recently drawn attention to an exact timedependent Boundary Conformal Field Theory with the spacetime interpretation of brane creation and annihilation. An interesting limit of this BCFT is formally equivalent to an array of Dbranes located in imaginary time. This raises the question: what is the meaning of Dbranes in imaginary time? The answer we propose is that Dbranes in imaginary time define purely closed string backgrounds. In particular we prove that the disk scattering amplitude of m closed strings off an arbitrary configuration of imaginary branes is equivalent to a sphere amplitude with m + 1 closed string insertions. The extra puncture is a specific closed string state, generically normalizable, that depends on the details of the brane configuration. We study in some detail the special case of the array of imaginary Dbranes related to Sen’s BCFT and comment on its spacetime interpretation. We point out that a certain limit of our setup allows to study classical black hole creation and suggests a relation between Choptuik’s critical behavior and a phasetransition à la GregoryLaflamme. We speculate