nucl-th digest · Mar 7, 2016

[Submitted on 17 Nov 2015] (cross-list from hep-th)

Inverse Magnetic/Shear Catalysis

It is well known that very large magnetic fields are generated when the Quark-Gluon Plasma is formed during peripheral heavy-ion collisions. Lattice, holographic, and other studies strongly suggest that these fields may, for observationally relevant field values, induce "inverse magnetic catalysis", signalled by a lowering of the critical temperature for the chiral/deconfinement transition. The theoretical basis of this effect has recently attracted much attention; yet so far these investigations have not included another, equally dramatic consequence of the peripheral collision geometry: the QGP acquires a large angular momentum vector, parallel to the magnetic field. Here we use holographic techniques to argue that the angular momentum can also, independently, have an effect on transition temperatures, and we obtain a rough estimate of the relative effects of the presence of both a magnetic field and an angular momentum density. We find that the shearing angular momentum reinforces the effect of the magnetic field at low values of the baryonic chemical potential, but that it can actually decrease that effect at high chemical potentials.

Comments:: 23 pages, 3 figures, version to appear in NPB
Subjects:: High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:: 1511.05293 [pdf]

NPB(2016)·29 citations

Charmed partner of the exotic

X (5568)

state and its properties

The mass, decay constant and width of a hypothetical charmed partner

X_{c}

of the newly observed exotic

X_{b} (5568)

state are calculated using a technique of QCD sum rule method. The

X_{c} = [s u] [c d]

state with

J^{P} = 0^{+}

is described employing two types of the diquark-antidiquark interpolating currents. The evaluation of the mass

m_{X_{c}}

and decay constant

f_{X_{c}}

is carried out utilizing the two-point sum rule method by including vacuum condensates up to eight dimensions. The widths of the decay channels

X_{c} \to D_{s}^{-} π^{+}

and

X_{c} \to D^{0} K^{0}

are also found. To this end, the strong couplings

g_{X_{c} D_{s} π}

and

g_{X_{c} D K}

are computed by means of QCD sum rules on the light-cone and soft-meson approximation.

Comments:: 7 Pages, 2 Figures and 3 Tables
Subjects:: High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:: 1603.01471 [pdf]

PRD(2016)·49 citations

Monday·March 7, 2016

Inverse Magnetic/Shear Catalysis

Charmed partner of the exotic $X (5568)$ state and its properties

Affiliations

Inverse Magnetic/Shear Catalysis

Charmed partner of the exotic X(5568) state and its properties

Affiliations

Charmed partner of the exotic $X (5568)$ state and its properties