Search

We compute the leading order (LO) $qg\to q \gamma$ and next-to-leading order (NLO) $gg\to q{\bar q} \gamma$ contributions to inclusive photon production in proton-proton (p+p) collisions at the LHC. These channels provide the dominant contribution at LO and NLO for photon transverse momenta $k_{\gamma\perp}$ corresponding to momentum fractions of $x\leq 0.01$ in the colliding protons. Our computations, performed in the dilute-dense framework of the Color Glass Condensate effective field theory (CGC EFT), show that the NLO contribution dominates at small-$x$ because it is sensitive to $k_\perp$-dependent unintegrated gluon distributions in both of the protons. We predict a maximal $10\%$ modification of the cross section at low $k_{\gamma\perp}$ as a direct consequence of the violation of $k_\perp$-factorization. The coherence effects responsible for this modification are enhanced in nuclei and can be identified from inclusive photon measurements in proton-nucleus collisions. We provide numerical results for the isolated inclusive photon cross section for $k_{\gamma\perp}\leq 20$ GeV in p+p collisions that can be tested in the future at the LHC., Comment: 9 pages, 5 figures

Quite independently of the Goldstone phenomenon, recent lattice data suggest the existence of gap-less modes in the spontaneously broken phase of a $\lambda \Phi^4$ theory. This result is a direct consequence of the quantum nature of the `Higgs condensate' that cannot be treated as a purely classical c-number field., Comment: 6 pages

The analytical perturbative approach, if taken to the limit of its applicability, allows one to predict an energy independent limit for the one-particle invariant density in QCD jets E dn d 3 p at very small momenta p. This is a direct consequence of the colour coherence in soft gluon branching. The existing data on the charged and identified particle inclusive spectra follow this prediction surprisingly well. Further tests of the perturbatively based picture in the soft region are discussed.

It is shown that in the absence of free abelian gauge fields, the conserved currents of (classical) Yang-Mills gauge models coupled to matter fields can be always redefined so as to be gauge invariant. This is a direct consequence of the general analysis of the Wess-Zumino consistency condition for Yang-Mills theory that we have provided recently., Comment: 12 pages, latex, no figures, version to appear in Phys. Lett. B

We formulate the theory of K 0 K 0 pairs by including variables which determine when the two kaons will undergo a simultaneous jump of strangeness. This approach is a direct consequence of the EPR reality criterion when locality is also taken into account. The probabilities of observing K 0 K 0 and K S K 0 pairs at different proper times are shown to disagree with quantum mechanical predictions up to 25%. The experimental study of such deviations could be easily performed in a Φ factory.

The inclusive nonleptonic decay of the Λc+ is reanalyzed using a nonrelativistic quark model representation of the Λc+- wavefunction. It is shown that the same approximation which leads to the familiar spectator and annihilation type contributions naturally also gives interference terms as a direct consequence of Fermi statistics. Numerical estimates which include these novel contributions, are presented for the Λc+ lifetime and semileptonic branching ratio.

Weak-electromagnetic interference in e + e − annihilation will in general give a non-vanishing average charge for particles emitted forward. We domonstrate a theorem stating that the total average forward charge vanishes as a direct consequence of cancellation of anomalies. Calculations are given for the average dependent forward charge in realistic experimental conditions when certain channels are excluded.

We show that the binding energy of the η-mesic nucleus does not increase monotonically with the ηNN ∗ (1535) coupling constant. This feature is a direct consequence of the unitarity constaint on the ηN interaction.