33472339
Gravitational corrections to Yukawa and phi{4} interactions.
We consider the lowest order quantum gravitational corrections to Yukawa and phi{4} interactions. Our results show that quantum gravity leads to contributions to the running coupling constants if the particles are massive and therefore alters the scaling behavior of the standard model. Furthermore, we find that the gravitational contributions to the running of the masses vanish.
119223768
No Lee-Wick Fields out of Gravity
We investigate the gravitational one-loop divergences of the standard model in large extra dimensions, with gravitons propagating in the ($4+\ensuremath{\delta}$)-dimensional bulk and gauge fields as well as scalar and fermionic multiplets confined to a three-brane. To determine the divergences we establish a cutoff regularization which allows us to extract gauge-invariant counterterms. In contrast to the claim of a recent paper [F. Wu and M. Zhong, Phys. Rev. D 78, 085010 (2008).], we show that the fermionic and scalar higher derivative counterterms do not coincide with the higher derivative terms in the Lee-Wick standard model. We argue that even if the exact Lee-Wick higher derivative terms were found, as in the case of the pure gauge sector, this would not allow to conclude the existence of the massive ghost fields corresponding to these higher derivative terms in the Lee-Wick standard model.
120318226
Hadron ratio fluctuations in heavy-ion collisions
16599979
Global Properties of Nucleus-Nucleus Collisions
QCD as a theory of extended, strongly interacting matter is familiar from big bang evolution which, within the time interval from electro-weak decoupling (10−12 s) to hadron formation (5 × 10−6 s), is dominated by the expansion of quark–gluon matter, a color conducting plasma that is deconfined. In the 1970s deconfinement was predicted [1–5] to arise from the newly discovered “asymptotic freedom” property of QCD; i.e., the plasma was expected to be a solution of perturbative QCD at asymptotically high square momentum transfer Q 2, or temperature T
119462879
High pT spectra of identified particles produced in Pb+Pb collisions at 158 A GeV beam energy
Results of the NA49 collaboration on the production of hadrons with large transverse momentum in Pb+Pb collisions at 158 A GeV beam energy are presented. A range of up to pT = 4 GeV/c is covered. The nuclear modification factor RCP is extracted for π±, K± and p, and the baryon to meson ratios and Λ/K0s are studied. All results are compared to other measurements at SPS and RHIC and to theoretical calculations.