Probing compositeness with Higgs Boson decays at the LHC

We study how massive ghost-free gravity \(f(R)\) -modified theories, MGFTs, can be encoded into generic off-diagonal Einstein spaces. Using “auxiliary” connections completely defined by the metric fields and adapted to nonholonomic frames with associated nonlinear connection structure, we decouple and integrate in certain general forms the field equations in MGFT. Imposing additional nonholonomic constraints, we can generate Levi-Civita, LC, configurations and mimic MGFT effects via off-diagonal interactions of effective Einstein and/or Einstein–Cartan gravity with nonholonomically induced torsion. We show that imposing nonholonomic constraints it is possible reproduce very specific models of massive \(f(R)\) gravity studied in Cai et al. (arXiv:1307.7150, 2013), Klusoňet al. (Phys Lett B 726:918, 2013), Nojiri and Odintov (Phys Lett B 716:377, 2012) and Nojiri et al. (JCAP 1305:020, 2013). The cosmological evolution of ghost-free off-diagonal Einstein spaces is investigated. Certain compatibility of MGFT cosmology to small off-diagonal deformations of \(\Lambda \) CDM models is established.     

Background and signal estimation for a low mass Higgs boson at the LHC

The discovery of the Higgs boson(s) is the major goal of the LHC which will start taking data in 2008. In this work a data driven extraction of the background and statistical signal significance in the H→ZZ→4ℓ decay channel is presented. The background for Higgs masses as low as 130 GeV can be extracted with an error of 20%, using a sideband measurement from a single 30 fb^-1 experiment. The predicted background distribution is best described by a double asymmetric Gaussian. An analytic formula is introduced which provides an accurate p-value that a Higgs discovery claim is consistent with a background fluctuation. The formula can be used in a single real measurement at LHC using as input the measured background and the profile likelihood asymmetric errors of this measurement. The method presented here can be applied to the general case of extrapolating from a signal-free data region to a candidate signal region. This is the case of supersymmetry searches at the LHC. PACS  14.80.Bn; 06.20.Dk     

Lambda spectra in 11.6A GeV/c Au-Au collisions

E896 has measured Lambda production in 11.6A GeV/c Au-Au collisions over virtually the whole rapidity phase space. The midrapidity p(t) distributions have been measured for the first time at this energy and appear to indicate that the Lambda hyperons have different freeze-out conditions than protons. A comparison with the relativistic quantum molecular dynamics model shows that while there is good shape agreement at high rapidity the model predicts significantly different slopes of the m(t) spectra at midrapidity. The data, where overlap occurs, are consistent with previously reported measurements.     

A 2D fit with background measurement constraints to boost the Higgs →ZZ<Superscript>(∗)</Superscript>→4<Emphasis Type="Italic">ℓ</Emphasis> discovery potential at the LHC

A data-driven method for simultaneously extracting a potential Higgs → ZZ^(∗) → 4e, 4μ, 2e2μ signal and its dominant backgrounds, is presented. The method relies on a combined fit of the 2-lepton, Z^(∗), and 4-lepton invariant masses. The fit is assisted by normalization of the Z+X backgrounds in data control regions. The Higgs discovery potential for the next few years of LHC running is presented. The demonstrated high sensitivity of the method makes it ideal for the search performed by the ATLAS and CMS experiments.