16 research outputs found
The (1+1)-dimensional Massive sine-Gordon Field Theory and the Gaussian Wave-functional Approach
The ground, one- and two-particle states of the (1+1)-dimensional massive
sine-Gordon field theory are investigated within the framework of the Gaussian
wave-functional approach. We demonstrate that for a certain region of the
model-parameter space, the vacuum of the field system is asymmetrical.
Furthermore, it is shown that two-particle bound state can exist upon the
asymmetric vacuum for a part of the aforementioned region. Besides, for the
bosonic equivalent to the massive Schwinger model, the masses of the one boson
and two-boson bound states agree with the recent second-order results of a
fermion-mass perturbation calculation when the fermion mass is small.Comment: Latex, 11 pages, 8 figures (EPS files
The Non-Trivial Effective Potential of the `Trivial' lambda Phi^4 Theory: A Lattice Test
The strong evidence for the `triviality' of (lambda Phi^4)_4 theory is not
incompatible with spontaneous symmetry breaking. Indeed, for a `trivial' theory
the effective potential should be given exactly by the classical potential plus
the free-field zero-point energy of the shifted field; i.e., by the one-loop
effective potential. When this is renormalized in a simple, but nonperturbative
way, one finds, self-consistently, that the shifted field does become
non-interacting in the continuum limit. For a classically scale-invariant (CSI)
lambda Phi^4 theory one finds m_h^2 = 8 pi^2 v^2, predicting a 2.2 TeV Higgs
boson. Here we extend our earlier work in three ways: (i) we discuss the
analogy with the hard-sphere Bose gas; (ii) we extend the analysis from the CSI
case to the general case; and (iii) we propose a test of the predicted shape of
the effective potential that could be tested in a lattice simulation.Comment: 22 pages, LaTeX, DE-FG05-92ER40717-
Restoration and Dynamical Breakdown of the \phi \to -\phi Symmetry in the (1+1)-dimensional Massive sine-Gordon Field Theory
Within the framework of the Gaussian wave-functional approach, we investigate
the influences of quantum and finite-temperature effects on the
Z_2-symmetry(\phi \to -\phi) of the (1+1)-dimensional massive sine-Gordon field
theory. It is explicitly demonstrated that by quantum effects the Z_2-symmetry
can be restored in one region of the parameter space and dynamically
spontaneously broken in another region. Moreover, a finite-temperature effect
can further restore the Z_2-symmetry only.Comment: 12 pages, 14 figures (EPS
Search for gluinos in events with an isolated lepton, jets and missing transverse momentum at âs=13 TeV with the ATLAS detector
The results of a search for gluinos in final states with an isolated electron or muon, multiple jets and large missing transverse momentum using protonâproton collision data at a centre-of-mass energy of âs=13 TeV are presented. The dataset used was recorded in 2015 by the ATLAS experiment at the Large Hadron Collider and corresponds to an integrated luminosity of 3.2 fbâ1. Six signal selections are defined that best exploit the signal characteristics. The data agree with the Standard Model background expectation in all six signal selections, and the largest deviation is a 2.1 standard deviation excess. The results are interpreted in a simplified model where pair-produced gluinos decay via the lightest chargino to the lightest neutralino. In this model, gluinos are excluded up to masses of approximately 1.6 TeV depending on the mass spectrum of the simplified model, thus surpassing the limits of previous searches