arXiv subjects

Bartosz Fornal

Publications and source records attributed to Bartosz Fornal.

52 records · Page 3Linked to original sources

arXiv2015

MSSM with gauged baryon and lepton numbers

A simple extension of the minimal supersymmetric standard model in which baryon and lepton numbers are local gauge symmetries spontaneously broken at the supersymmetry scale is reported. This theory provides a natural explanation for proton stability. Despite violating R-parity, it contains a dark matter candidate carrying baryon number that can be searched for in direct detection experiments. The model accommodates a light active neutrino spectrum and predicts one heavy and two light sterile neutrinos. It also allows for lepton number violating processes testable at the Large Hadron Collider.

hep-ph↗

arXiv2015

Baryon Number as the Fourth Color

We propose an extension of the Standard Model in which baryon number is promoted to be part of a non-Abelian gauge symmetry at high energies. Specifically, we consider the gauge group SU(4) x SU(2)_L x U(1)_X, where the SU(4) unifies baryon number and color. This symmetry is spontaneously broken down to the Standard Model gauge group at a scale which can be as low as a few TeV. The SU(4) structure implies that each SM quark comes along with an uncolored quark partner, the lightest of which is stabilized by the generalized baryon number symmetry and can play the role of dark matter. We explore circumstances under which one can realize a model of asymmetric dark matter whose relic abundance is connected to the observed baryon asymmetry, and discuss unique signatures that can be searched for at the LHC.

hep-ph↗

arXiv2013

B and L at the SUSY Scale, Dark Matter and R-parity Violation

We present a simple theory where baryon and lepton numbers are spontaneously broken at the supersymmetry scale. In this context R-parity must be spontaneously broken but the theory still contains a stable field which can play the role of the cold dark matter of the Universe. We discuss the spectrum of the theory, the properties of the dark matter candidate and the predictions for direct detection experiments. This theory provides a concrete example of exotic supersymmetric signatures associated with having the simultaneous presence of R-parity violating and missing energy signals at the Large Hadron Collider.

hep-ph↗

arXiv2013

Phenomenology of scalar leptoquarks

We study the simplest renormalizable scalar leptoquark models where the standard model is augmented only by one additional scalar representation of SU(3) x SU(2) x U(1). The requirement that there be no proton decay from renormalizable interactions singles out two such models, one of which exhibits an unusual top mass enhancement of the mu -> e gamma decay rate. We analyze the phenomenology of the model with the unusual top mass enhancement of loop level chirality changing charged lepton processes in the light of existing and upcoming experiments. Both of the models that do not allow proton decay from renormalizable interactions have dimension five operators that, even if suppressed by the Planck scale, can give rise to an unacceptably high level of baryon number violation. We discuss symmetries that can forbid these dimension five operators.

hep-ph↗

arXiv2012

Simplified models with baryon number violation but no proton decay

We enumerate the simplest models that have baryon number violation at the classical level but do not give rise to proton decay. These models have scalar fields in two representations of SU(3) x SU(2) x U(1) and violate baryon number by two units. Some of the models give rise to neutron-antineutron oscillations, while some also violate lepton number by two units. We discuss the range of scalar masses for which neutron-antineutron oscillations are measurable in the next generation of experiments. We give a brief overview of the phenomenology of these models and then focus on one of them for a more quantitative discussion of neutron-antineutron oscillations, the generation of the cosmological baryon number, the electric dipole moment of the neutron, and neutral kaon mixing.

hep-ph↗

arXiv2012

Supersymmetric Dark Matter Sectors

We investigate the properties of a dark matter sector where supersymmetry is a good symmetry. In this context we find that the stability of the dark matter candidate is possible even when R-parity is broken in the visible sector. In order to illustrate the idea we investigate a simple scenario where the dark matter candidate is the lightest scalar field in the dark sector which annihilates mainly into two sfermions when these channels are available. We study the relic density constraints and the predictions for the dark matter detection experiments.

hep-ph↗

arXiv2012

Particle creation in a toroidal universe

We calculate the particle production rate in an expanding universe with a three-torus topology. We discuss also the complete evolution of the size of such a universe. The energy density of particles created through the nonzero modes is computed for selected masses. The unique contribution of the zero mode and its properties are also analyzed.

hep-th↗

arXiv2012

On Higgs Decays, Baryon Number Violation, and SUSY at the LHC

Baryon number violating interactions could modify the signatures of supersymmetric models at the Large Hadron Collider. In this article we investigate the predictions for the Higgs mass and the Higgs decays in a simple extension of the minimal supersymmetric standard model where the local baryon and lepton numbers are spontaneously broken at the TeV scale. This theory predicts baryon number violation at the low scale which can change the current LHC bounds on the supersymmetric spectrum. Using the ATLAS and CMS bounds on the Higgs mass we show the constraints on the sfermion masses, and show the subsequent predictions for the radiative Higgs decays. We found that the Higgs decay into two photons is suppressed due to the existence of new light leptons. In this theory the stops can be very light in agreement with all experimental bounds and we make a brief discussion of the possible signals at the LHC.

hep-ph↗

arXiv2011

Color octet scalars and high pT four-jet events at LHC

We study the effect of color octet scalars on the high transverse momenta four-jet cross section at the LHC. We consider both weak singlet and doublet scalars, concentrating on the case of small couplings to quarks. We find that a relatively early discovery at the LHC is possible for a range of scalar masses.

hep-ph↗

arXiv2011

Standard model with compactified spatial dimensions

We analyze the structure of the standard model coupled to gravity with spatial dimensions compactified on a three-torus. We find that there are no stable one-dimensional vacua at zero temperature, although there does exist an unstable vacuum for a particular set of Dirac neutrino masses.

hep-th↗

arXiv2011

Finite Temperature Structure of the Compactified Standard Model

We analyze the finite temperature structure of the standard model coupled to gravity with one and two dimensions compactified (on a circle and a torus). We find that finite temperature effects wash out any vacua which exist at zero temperature. We also discuss the possibility of transitions between the four-dimensional universe and the lower-dimensional spacetimes.

hep-th↗

arXiv2011

Standard Model Vacua for Two-dimensional Compactifications

We examine the structure of lower-dimensional standard model vacua for two-dimensional compactifications (on a 2D torus and on a 2D sphere). In the case of the torus we find a new standard model vacuum for a large range of neutrino masses consistent with experiment. Quantum effects play a crucial role in the existence of this vacuum. For the compactification on a sphere the classical terms dominate the effective potential for large radii and a stable vacuum is achieved only by introducing a large magnetic flux. We argue that there are no two-dimensional standard model vacua for compactifications on a surface of genus greater than one.

hep-th↗

arXiv2010

Prospects and Constraints for Vector-like MFV Matter at LHC

We examine the prospects for LHC discovery of SU(2)_L singlet vector-like quarks that obey Minimal Flavour Violation (MFV) and are consistent with lower energy phenomenology. We study models where the vector-like quarks have the same quantum numbers as u_R or d_R, allowing mixing, which generally leads to significant low energy constraints. We find that there are two naturally phenomenologically viable MFV models of this type when the Weyl spinor components of the vector-like quarks are flavour triplets. We examine direct production bounds, flavour and electroweak precision data constraints for these models and determine the cross section for allowed values of the model parameters at LHC. For the models we identify as naturally phenomenologically viable, large amounts of parameter space afford a significant early discovery reach at LHC while being consistent with lower energy phenomenology.

hep-ph↗

arXiv2010

High pT Production of b\bar{b} at LHC and New SU(3) Bosons

We discuss the potential of measurements of σ(p p -> b\bar{b}) to constrain new bosonic degrees of freedom at the LHC when pT > \sqrt{s}/11 TeV for a pseudorapidity cut |η| < 2.4. By suppressing the NLO QCD production of b\bar{b} pairs through simple kinematic constraints we show how to more efficiently exploit CMS's reach out to 1.5 TeV in pT for B mesons in searches for new physics. Using this technique we investigate the potential for discovery of new massive spin one and spin zero SU_c(3) octet bosons by analyzing their effect on the dσ(p p -> b\bar{b})/d pT^2 distribution. In some cases, the tree level contributions are small and the largest effect of new physics on the pT tail of the distribution is due to one-loop resonant s-channel production or interference effects with the LO standard model production mechanisms q\bar{q}, g g -> b\bar{b}. We explore this possibility in some detail when the standard model is extended with an (8,2)_{1/2} scalar motivated by Minimal Flavor Violation.

hep-ph↗

arXiv2009

Lee-Wick Theories at High Temperature

An extension of the standard model, the Lee-Wick standard model, based on ideas of Lee and Wick was recently introduced. It does not contain quadratic divergences in the Higgs mass and hence solves the hierarchy puzzle. The Lee-Wick standard model contains new heavy Lee-Wick resonances at the TeV scale that decay to ordinary particles. In this paper we examine the behavior of Lee-Wick resonances at high temperature. We argue that they contribute negatively to the energy density rho and pressure p and at temperatures much greater than their mass M their O(T^4) contributions to rho and p cancel against those of the ordinary (light) particles. The remaining O(M^2*T^2) contributions are positive and result in an equation of state that approaches w=1 from below as T goes to infinity.

hep-th↗

arXiv2006

A Survey of Open Clusters in the u'g'r'i'z' Filter System: III. Results for the Cluster NGC 188

We continue our series of papers describing the results of a photometric survey of open star clusters, primarily in the southern hemisphere, taken in the u'g'r'i'z' filter system. The entire observed sample covered more than 100 clusters, but here we present data only on NGC 188, which is one of the oldest open clusters known in the Milky Way. We fit the Padova theoretical isochrones to our data. Assuming a solar metallicity for NGC 188, we find a distance of 1700+/-100 pc, an age of 7.5+/-0.7 Gyr, and a reddening E(B-V) of 0.025+/-0.005. This yields a distance modulus of 11.23+/-0.14.

astro-ph↗