We review the formulation of Landau hydrodynamics and find that the rapidity distribution of produced particles in the center-of-mass system should be more appropriately modified as dN/dy ∝ exp{ p y 2 b − y 2 }, where y b = ln{ √ sNN /mp} is the beam nucleon rapidity, instead of Lan-The modified distribution agrees better with experimental dN/dy data than the original Landau distribution and can be represented well by the Gaussian distribution, dN/dy(Gaussian) ∝ exp{−y 2 /2L}. Past successes of the Gaussian distribution in explaining experimental rapidity data can be understood, not because it is an approximation of the original Landau distribution, but because it is in fact a close representation of the modified distribution. Predictions for pp and AA collisions at LHC energies in Landau hydrodynamics are presented.

We explore molecular states of two open heavy-quark mesons (Qq)-(qQ) in a quark-based model in terms of a four-body non-relativistic Hamiltonian with pairwise effective interactions. Molecular states are found in the combinations of {D,

Phenomenological Tsallis fits to the CMS, ATLAS, and ALICE transverse momentum spectra of hadrons for pp collisions at LHC were recently found to extend over a large range of the transverse momentum. We investigate whether the few degrees of freedom in the Tsallis parametrization may arising from the relativistic parton-parton hard-scattering and related processes. The effects of the multiple hard-scattering and parton showering processes on the power law are discussed. We find empirically that whereas the transverse spectra of both hadrons and jets exhibit power-law behavior of 1/p n T at high pT , the power indices n for hadrons are systematically greater than those for jets, for which n∼4-5.

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