Related papers: Speculations on ALEPH's Dijet Enhancement
We investigate a possibility for explaining the recently announced 750\,GeV diphoton excess by the ATLAS and the CMS experiments at the CERN LHC in a model with multiple doubly charged particles, which was originally suggested for…
We discuss production of four jets $pp \rightarrow j j j j X$ with at least two jets with large rapidity separation in proton-proton collisions at the LHC through the mechanism of double-parton scattering (DPS). The cross section is…
A general search for the pair production of resonances, each decaying to two quarks, is reported. The search is conducted separately for heavier resonances (masses above 400 GeV), where each of the four final-state quarks generates a…
The impact of virtual leptoquark or R-parity breaking squark exchange as well as generic contact interactions on the production of quark-antiquark pairs in $e^+e^-$ annihilation, in particular at LEP2, is summarized. An exciting possibility…
We study the enhanced production of charmed baryons relative to charmed mesons in proton--proton collisions at LHC energies. Utilizing PYTHIA 8 simulations with enhanced color-reconnection we propose methods based on the comparative use of…
In a recent work from the ALICE collaboration an excess of relatively soft dilepton pairs was reported in p+p collisions at $13$ TeV. In the report no satisfactory explanation was found via standard bremsstrahlung computations. In this…
Given the hints of lepton-flavour non-universality in semi-leptonic $B$ decays, leptoquark (LQ) models with sizeable couplings to heavy-quark flavours are enjoying a renaissance. While such models are subject to stringent constraints from…
I discuss event cuts in DIS which improve the similarity between the current Breit hemisphere and hemispheres in $e^+e^-$ annihilation. I also present a method to study the scale evolution in quark hemispheres using data from fixed energy…
Heavy quark production in five jet events at $e^+e^-$ colliders is studied at tree level using helicity amplitudes. Total production rates for $2b3j$ and $4bj$ are given and compared with the corresponding results for massless quarks. The…
A search is performed for top quark pairs with early data of ATLAS pp collision taken at {\surd}s = 7 TeV. Several candidate events are observed, in both lepton plus jets and dilepton channels. The properties of these events are described,…
Superposition of jets of different flavors as well as superposition of jets of different topologies describe well observed structures (shoulder, H_q oscillations) in e+e- annihilation. The analysis of similar effects seen in experimental…
We present a theoretical study of the medium modifications of the $p_T$ balance ($x_J$) of dijets in Xe+Xe collisions at $\sqrt{s_{NN}}=5.44$ TeV. The initial production of dijets was carried out using the POWHEG+PYTHIA8 prescription, which…
I will review the measurements of the $b$-quark mass performed by ALEPH and DELPHI. A large set of observables has been used together with detailed studies on jet algorithms. Very clear effects due to the $b$-quark mass running are…
A resonance in the diphoton channel with invariant mass $m_{\gamma \gamma} = 750$ GeV was claimed by the ATLAS and CMS collaborations at the run-2 LHC with $\sqrt{s}=13$ TeV. In this paper, we explain this diphoton excess as a pseudo-scalar…
As a result of the helicity suppression effect, within the Standard Model the rare decay channel $B_s \to e^+ e^-$ has a decay probability which is five orders of magnitude below current experimental limits. Thus, any observation of this…
Using a recently-developed perturbative-QCD approach for jet evolution in a dense quark-gluon plasma, we study the nuclear modification factor for the jet fragmentation function. The qualitative behaviour that we find is in agreement with…
An azimuthal angle correlation between the two hardest jets is studied in the ttbar production process at the 14 TeV LHC. The event samples are generated by merging the tree level matrix elements for the ttbar plus up to 2 or 3 partons with…
Energetic jets that traverse the quark-gluon plasma created in heavy-ion collisions serve as excellent probes to study this new state of deconfined QCD matter. Presently, however, our ability to achieve a crisp theoretical interpretation of…
A search is presented for the electroweak production of a top quark pair in association with a $W$ boson and at least one additional jet, known as the ${t\bar{t}W\kern-0.2em j_{\mathrm{EW}}}$ process. This process has embedded within it a…
Top quark studies at future $e^+e^-$ colliders are considered. Two issues are discussed: {a --}Some results are presented on the decays of top quarks. Energy distributions of charged leptons and neutrinos in $t\to bW\to be^+\nu$ and jets in…