Related papers: A Scenario for Contact Interactions at HERA
In the framework of the minimal supersymmetric standard model (MSSM) with $R-$parity violation, the high--$Q^2$ HERA events can be interpreted as the $s-$channel production of a single stop of $M_{\tilde{t}_1} \approx 200$ GeV, whose…
At HERA, the large flux of almost real photons accompanying the electron beam leads to the copious photoproduction of jets. Regions of small momentum fractions $x$ of the incoming particles are explored, where the density of partons is…
Attempts to understand the recent observation of an excess of events in the neutral and charged current channels at high$-Q^2$ at HERA has provided an excellent example of how experiments at both low and high energies can be used to…
Quark-quark and quark-lepton searches for compositenss at the Fermilab Tevatron are summarized. These are of the contact-interaction variety where sqrt(s-hat) < the hypothesized mass scales, Lambda. Tevatron experiments limit a variety of…
A search for first generation scalar and vector leptoquarks produced in ep collisions is performed by the H1 experiment at HERA. The full H1 data sample is used in the analysis, corresponding to an integrated luminosity of 446 pb^-1. No…
We consider the $L$-$R$ symmetric composite model for quarks and leptons where constituent preons possessing some local $SU(N)_{MF}$ metaflavor symmetry are bound by the chiral $SO(n)_{L}\times SO(n)_{R}$ gauge metacolor forces. The…
We present a summary of results for searches for new particles and interactions at the Fermilab Tevatron collider by the CDF and the D0 experiments. These include results from Run I as well as Run II for the time period up to July 2014. We…
Four fermion interactions appear in many models of Beyond Standard Model physics. In Technicolour and composite Higgs models Standard Model fermion masses can be generated by four fermion terms. They are also expected to modify the dynamics…
Given the eventuality of neutrino and muon factories in the foreseeable future, all possible 2-to-2 processes involving two neutrinos, whether Dirac or Majorana ones, and two charged fermions are considered on the basis of the most general…
Recent results on spectroscopy with special focus on searches for pentaquarks are presented from the H1 and ZEUS collaborations. Cross sections of observed states and upper limits on the production cross section of unobserved states are…
Quarks, leptons and heavy vector bosons are suggested to be composed of stable spin-1/2 preons, existing in three flavours, combined according to simple rules. Straightforward consequences of an SU(3) preon-flavour symmetry are the…
The search for events containing isolated leptons (electrons or muons) and missing transverse momentum produced in $e^{\pm}p$ collisions is performed with the H1 detector at HERA in the period 1994--2005. The analysed data sample…
It is shown that quarks and leptons can couple intrinsically to pure supergravity, preserving for this context the degeneracy of globally supersymmetric vacua, and specifically preserving the vacuum that is characterized by SU(4)XU(1). A…
Measurements of Deep-Inelastic Neutral and Charged current interactions are presented in lepton proton scattering at HERA. The measurements are obtained from taken during 1996 to 1999 and consists of $30 \rm{pb^{-1}}$ of $e^+p$ and $16…
Motivated by the recent HERA events which are consistent with a possible leptoquark interpretation, we discuss the prospects for including additional light colour triplets and anti-triplets in the spectrum of supersymmetric unified…
A search for leptoquarks at HERA was performed in H1 using 1994 $e^+ p$ data corresponding to an integrated luminosity of about $3 \pb^{-1}$. Single leptoquarks were searched for in direct positron-quark fusion processes taking into account…
The direct charmonium and bottomonium production rate observed at high-pt in pp-bar collisions at the Tevatron is factors of ten larger than predictions based on conventional perturbative QCD. We show that this excess can be accounted for…
Mixing between bosons that transform differently under the standard model gauge group, but identically under its unbroken subgroup, can induce interactions that violate the total lepton number. We discuss four-fermion operators that mediate…
The role of Sinister Heavy Fermions in recent Glashow's SU(3)*SU(2)*SU(2)'*U(1) model is to offer in a unique frame relic Helium-like products (an ingenious candidate to the dark matter puzzle), a solution to the See-Saw mechanism for light…
A search for second and third generation scalar and vector leptoquarks produced in ep collisions via the lepton flavour violating processes ep -> mu X and ep -> tau X is performed by the H1 experiment at HERA. The full H1 ep data sample…