Related papers: A possible evidence of pion condensation
Collisions between nuclei at ultrarelativistic energies produce a color-deconfined plasma that expands explosively and rapidly reverts to the color-confined (hadronic) state. In non-central collisions, the zone of hot matter is transversely…
Soft-pion theorems are used to show how chiral symmetry constrains the contributions of low-momentum pions to the quark condensate, the pion decay constant and hadron masses, all of which have been proposed as signals of partial restoration…
Collisions of cosmic ray particles with ultra-high initial energies with nuclei in the atmosphere open a wide room for appearing of the novel dynamical features for multiparticle production processes. In particular, the pion-lasing behavior…
Being simultaneously a bound state and a pseudo-Goldstone boson of chiral symmetry breaking, the pion is an ideal probe of the intertwined phenomena of confinement and chiral symmetry breaking in QCD. Here, we compute the low energy pion…
Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We estimate the soft contributions to this process, with an eye toward delineating the region where…
Recent DESY-HERA data on $J/\Psi$ elasticity distribution show that it emerges mostly as a fast particle. Interpreting photoproduction as a collision between a pre-formed charmed hadron and the proton, the outcoming $J/\Psi$ is a leading…
We investigate the dynamical possibility for the formation of a transient new coherent condition of matter in high--energy hadronic collisions. The coherent bosonic amplitude is characterized by a non--zero momentum and is sustained by $P…
We revisit the description of pion production in proton-proton collisions in the light of the very precise data taken at the Large Hadron Collider (LHC) over the past decade. First attempts to include LHC results in next-to-leading order…
We study the collider signatures of new pions, composite particles which emerge from a TeV-scale, confining gauge theory with vector-like matter. Similar to the neutral pion in QCD, these new pions mainly decay into a pair of standard model…
A search for forbidden and exotic Z boson decays in the diphoton mass spectrum is presented for the first time in hadron collisions, based on data corresponding to 10.0 fb^-1 of integrated luminosity from proton-antiproton collisions at…
In a strong magnetic field, B > 4x10^{12} G, gamma-rays emitted nearly along curved field lines adiabatically convert into bound electron-positron pairs (positronium atoms) rather that decaying into free pairs. This process may modify the…
The effects of pions for vacuum polarization in background magnetic fields are considered. The effects of quark condensates is also briefly addresses. Although these effects are out of the measurement accuracy of laboratory experiments they…
One of the portals to new physics is a light scalar coupled to the Standard Model (SM) Higgs. In this paper we focus on hadronic decays of such a scalar in the regime where QCD dynamics is nonperturbative, resulting, e.g., in decays to…
Instability of the charged pion vacuum resulting in the pion condensation is studied within the $\lambda|\phi|^4$ model at the rapid rotation of the system in presence of external fields. Case of the static external scalar and electric…
We investigate the influence of medium corrections to the pion dispersion relation on the pion dynamics in intermediate energy heavy ion collisions. To do so a pion potential is extracted from the in-medium dispersion relation and used in…
Protons with energies up to 10^15 eV are the main component[1] of cosmic rays, but evidence for the specific locations where they could have been accelerated to these energies has been lacking[2]. Electrons are known to be accelerated to…
In high energy Heavy Ion Collisions, the onset of the quark-gluon plasma is the colour glass condensate, dominated by gluons. The final state is hadronic, and dominated by pions and kaons. Here we investigate an effective approach of QCD…
I review recent progress made in the description of pion-nucleon scattering, the $\sigma$--term, the scalar form factor and the strangeness content of the nucleon in the framework of heavy baryon chiral perturbation theory. Other topics are…
Some unusual features observed in hadronic collisions at high energies can be understood assuming that gluons in hadrons are located within small spots occupying only about 10% of the hadron's area. Such a conjecture about the presence of…
Rare decays of light mesons may be a discovery window for a new weakly coupled forces hidden at low energy QCD scale. BES-III Collaboration reported the observation of the rare decay $\eta'\rightarrow\pi^0\gamma\gamma$. The observed decay…