ar X iv : h ep - p h / 01 05 19 3 v 1 1 8 M ay 2 00 1 Poincaré Invariant Algebra From Instant to Light - Front Quantization

ar X iv : h ep - t h / 01 05 31 8 v 1 3 1 M ay 2 00 1 Trace anomaly for 4 D higher derivative scalar - dilaton theory

Trace anomaly for conformally invariant higher derivative 4D scalar-dilaton theory is obtained by means of calculating divergent part of one-loop effective action for such system. Its applications are briefly mentioned.

ar X iv : h ep - t h / 01 01 05 9 v 2 1 4 M ay 2 00 1

We consider the complex scalar field coupled to background NC U(1) YM and calculate the correlator of two gauge invariant composite operators. We show how the noncommutative gauge invariance is restored for higher correlators (though the Green's function itself is not invariant). It is interesting that the recently discovered noncommutative solitons appear in the calculation.

ar X iv : h ep - p h / 01 05 19 8 v 1 1 9 M ay 2 00 1 ∂ m ∂ μ in the Nambu – Jona - Lasinio model

Using the Nambu–Jona-Lasinio (NJL) model we study responses of the pion and kaon masses to changes in the chemical potential, ∂m ∂μ , at zero and finite chemical potential. We find that the behavior of ∂m ∂μ for the pion is quite different from that for the kaon. Our results can give a clue for future studies of ∂m ∂μ on the lattice.

ar X iv : h ep - p h / 01 05 34 8 v 1 3 1 M ay 2 00 1 Ultrahigh energy cosmic rays as a Grand Unification signal

We analyze the spectrum of the ultrahigh energy (above ≈ 10 9 GeV) cosmic rays. With a maximum likelihood analysis we show that the observed spectrum is consistent with the decay of extragalactic GUT scale particles. The predicted mass for these superheavy particles is m X = 10 b GeV, where b = 14.6

ar X iv : h ep - p h / 02 05 01 6 v 1 2 M ay 2 00 2 Scalar a 0 ( 980 ) meson in φ → π 0 ηγ decay