12010699
Top quark mass predictions from gauge Yukawa unification
Gauge-Yukawa Unification (GYU) is a renormalization group invariant functional relation among gauge and Yukawa couplings which holds beyond the unification point in Grand Unified Theories (GUTs). Here, GYU is obtained by requiring finiteness and reduction of couplings to all orders in perturbation theory. We examine the consequences of GYU in various supersymmetric GUTs and in particular the predictions for the top quark mass. These predictions are such that they distinguish already GYU from ordinary GUTs. Moreover, when more accurate measurements of the top quark mass are available, it is expected that it will be possible to discriminate among the various GYUs.
121936366
Finite unified theories and the top quark mass
We present results of a study of two phenomenologically interesting SU (5) supersymmetric Grand Unified models, which are finite to all-loops before spontaneous symmetry breaking. The finiteness conditions provide us with relationships among the Yukawa and gauge couplings at the unification point, which in turn predict a heavy top quark mass (∼ 175 – 190 GeV).
118733088
Infrared Attractiveness in Extra Dimensions
We study the renormalization group flow and infrared structure of higher dimensional GUTs. In higher dimensional theories the couplings approach much faster the infrared fixed points, compared to the four‐dimensional case, due to their power law running behaviour. Therefore, tighter restrictions can be imposed to the couplings at the infrared region, enhancing thus the predictivity of the theories. We take a model with SU(5) as gauge group as a concrete example and show the running behaviour of the coupling constants. We also describe the predictions of low‐energy parameters, e.g. masses of the top quark and superparticles that result from the fixed point structure of the RGEs.
125202226
Finite unification at all-loops
16878005
Axial couplings on the world-line
Abstract We construct a world-line representation for the fermionic one-loop effective action with axial and also vector, scalar, and pseudo-scalar couplings. We use this expression to compute a few selected scattering amplitudes. These allow us to verify that our method yields the same results as standard field theory. In particular, we are able to reproduce the chiral anomaly. Our starting point is the second order formulation for the Dirac fermion. We translate the second order expressions into a world-line action.
182210475
Finiteness and GUTs
8753620
Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set.
We present a search for the standard model Higgs boson produced in association with a W boson in sqrt[s]=1.96  TeV pp collision data collected with the CDF II detector at the Tevatron corresponding to an integrated luminosity of 9.45  fb(-1). In events consistent with the decay of the Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a neutrino, we set 95% credibility level upper limits on the WH production cross section times the H→bb branching ratio as a function of Higgs boson mass. At a Higgs boson mass of 125  GeV/c(2), we observe (expect) a limit of 4.9 (2.8) times the standard model value.
14644401
Measurement of the top quark mass in the all-hadronic mode at CDF
Abstract A measurement of the top quark mass ( M top ) in the all-hadronic decay channel is presented. It uses 5.8 fb−1 of p p ¯ data collected with the CDF II detector at the Fermilab Tevatron Collider. Events with six to eight jets are selected by a neural network algorithm and by the requirement that at least one of the jets is tagged as a b-quark jet. The measurement is performed with a likelihood fit technique, which simultaneously determines M top and the jet energy scale (JES) calibration. The fit yields a value of M top = 172.5 ± 1.4 ( stat ) ± 1.0 ( JES ) ± 1.1 ( syst ) GeV / c 2 .
123048219
Measurement of the top quark mass in the dilepton channel using m(T2) at CDF
We present measurements of the top quark mass using m(T2), a variable related to the transverse mass in events with two missing particles. We use the template method applied to t (t) over bar dilepton events produced in p (p) over bar collisions at Fermilab's Tevatron Collider and collected by the CDF detector. From a data sample corresponding to an integrated luminosity of 3.4 fb(-1), we select 236 t (t) over bar candidate events. Using the m(T2) distribution, we measure the top quark mass to be M-top = 168.0(-4.0)(4.8)(stat) +/- 2.9(syst) GeV/c(2). By combining m(T2) with the reconstructed top quark mass distributions based on a neutrino weighting method, we measure M-top = 169.3 +/- 2.7(stat) +/- 3.2(syst) GeV/c(2). This is the first application of the m(T2) variable in a mass measurement at a hadron collider.
5768130
Search for supersymmetry with gauge-mediated breaking in diphoton events with missing transverse energy at CDF II.
We present the results of a search for supersymmetry with gauge-mediated breaking and chi(1)(0) --> gammaG in the gammagamma + missing transverse energy final state. In 2.6+/-0.2 fb(-1) of pp collisions at square root(s) = 1.96 TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4+/-0.4 events. We set limits on the cross section at the 95% C.L. and place the world's best limit of 149 GeV/c2 on the chi(1)(0) mass at tau(chi(1)(0)) << 1 ns. We also exclude regions in the chi(1)(0) mass-lifetime plane for tau(chi(1)(0)) approximately < 2 ns.
18284543
Measurement of the top pair production cross section in the lepton+jets channel using a jet flavor discriminant
We present a new method to measure the top quark pair production cross section and the background rates with data corresponding to an integrated luminosity of 2.7  fb-1 from pp collisions at √s=1.96  TeV collected with the CDF II Detector. We select events with a single electron or muon candidate, missing transverse energy, and at least one b-tagged jet. We perform a simultaneous fit to a jet flavor discriminant across nine samples defined by the number of jets and b tags. An advantage of this approach is that many systematic uncertainties are measured in situ and inversely scale with integrated luminosity. We measure a top cross section of σtt =7.64±0.57(stat+syst)±0.45(luminosity)  pb.