No Arabic abstract
In this report we review recent theoretical progress and the latest experimental results in jet substructure from the Tevatron and the LHC. We review the status of and outlook for calculation and simulation tools for studying jet substructure. Following up on the report of the Boost 2010 workshop, we present a new set of benchmark comparisons of substructure techniques, focusing on the set of variables and grooming methods that are collectively known as top taggers. To facilitate further exploration, we have attempted to collect, harmonise, and publish software implementations of these techniques.
It is widely considered that, for Higgs boson searches at the Large Hadron Collider, WH and ZH production where the Higgs boson decays to b anti-b are poor search channels due to large backgrounds. We show that at high transverse momenta, employing state-of-the-art jet reconstruction and decomposition techniques, these processes can be recovered as promising search channels for the standard model Higgs boson around 120 GeV in mass.
These proceedings discuss a possible new search strategy for a light Higgs boson at the LHC, in high-pt WH and ZH production where the Higgs boson decays to a single collimated b-bbar jet. Material is included that is complementary to what was shown in the original article, arXiv:0802.2470.
New strong interactions at the LHC may exhibit a richer structure than expected from simply rescaling QCD to the electroweak scale. In fact, a departure from rescaled QCD is required for compatibility with electroweak constraints. To navigate the space of possible scenarios, we use a simple framework, based on a 5D model with modifications of AdS geometry in the infrared. In the parameter space, we select two points with particularly interesting phenomenology. For these benchmark points, we explore the discovery of triplets of vector and axial resonances at the LHC.
We derive Feynman rules for the interactions of a single gravitino with (s)quarks and gluons/gluinos from an effective supergravity Lagrangian in non-derivative form and use them to calculate the hadroproduction cross sections and decay widths of single gravitinos. We confirm the results obtained previously with a derivative Lagrangian as well as those obtained with the non-derivative Lagrangian in the high-energy limit and elaborate on the connection between gauge independence and the presence of quartic vertices. We perform extensive numerical studies of branching ratios, total cross sections, and transverse-momentum spectra at the Tevatron and the LHC. From the latest CDF monojet cross section limit, we derive a new and robust exclusion contour in the gravitino-squark/gluino mass plane, implying that gravitinos with masses below $2cdot10^{-5}$ to $1cdot10^{-5}$ eV are excluded for squark/gluino-masses below 200 and 500 GeV, respectively. These limits are complementary to the one obtained by the CDF collaboration, $1.1cdot 10^{-5}$ eV, under the assumption of infinitely heavy squarks and gluinos. For the LHC, we conclude that SUSY scenarios with light gravitinos will lead to a striking monojet signal very quickly after its startup.
The present paper is based on the assumption that heavy quarks bound states exist in the Standard Model (SM). Considering New Bound States (NBS) of top-anti-top quarks (named T-balls) we have shown that: 1) there exists the scalar 1S--bound state of $6t+6bar t$; 2) the forces which bind the top-quarks are very strong and almost completely compensate the mass of the twelve top-anti-top-quarks in the scalar NBS; 3) such strong forces are produced by the Higgs-top-quarks interaction with a large value of the top-quark Yukawa coupling constant $g_tsimeq 1$. Theory also predicts the existence of the NBS $6t + 5bar t$, which is a color triplet and a fermion similar to the $t$-quark of the fourth generation. We have also considered the b-quark-replaced NBS, estimated the masses of the lightest fermionic NBS: $M_{NBS}gtrsim 300$ GeV, and discussed the larger masses of T-balls. We have developed a theory of the scalar T-balls condensate and predicted the existence of three SM phases. Searching for heavy quark bound states at the Tevatron and LHC is discussed. We have constructed the possible form-factors of T-balls, and estimated the charge multiplicity coming from the T-balls decays.