(Cont.) In the mid-rapidity region, the yield of charged particles evolves smoothly as a function of [the square root of] sNN and collision centrality. We compare our results with a compilation of data from lower energy p + p, p + A and A + A collisions and discuss their implications for various phenomenological models of particle production.

The first measurements made by the ATLAS experiment at the LHC are presented. The charged particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and pseudorapidity are measured for events with at least one charged particle in the kinematic range [small Greek letter eta] 2.5 and pT 500 MeV. The charged particle multiplicity distributions are measured at the three centre of mass energies at which protons have been collided in the LHC: 900 GeV, 2.36 TeV and 7 TeV. The results are compared to predictions from Monte Carlo models of proton-proton collisions. All models predicted a multiplicity at least 10\% lower than was measured. They also failed to predict a sufficient increase in the multiplicity when the centre of mass energy increased from 900 GeV to 7 TeV. Updated models have already been produced using these data, which provide a significantly better description of the properties of proton-proton collisions at LHC energies.

The first measurements made by the ATLAS experiment at the LHC are presented. The charged particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and pseudorapidity are measured for events with at least one charged particle in the kinematic range [small Greek letter eta] 2.5 and pT 500 MeV. The charged particle multiplicity distributions are measured at the three centre of mass energies at which protons have been collided in the LHC: 900 GeV, 2.36 TeV and 7 TeV. The results are compared to predictions from Monte Carlo models of proton-proton collisions. All models predicted a multiplicity at least 10\% lower than was measured. They also failed to predict a sufficient increase in the multiplicity when the centre of mass energy increased from 900 GeV to 7 TeV. Updated models have already been produced using these data, which provide a significantly better description of the properties of proton-proton collisions at LHC energies.

Measurements of midrapidity charged-particle multiplicity distributions, dNch/d[eta], and midrapidity transverse-energy distributions, dET/d[eta], are presented for a variety of collision systems and energies. Included are distributions for Au+Au collisions at √sNN=200, 130, 62.4, 39, 27, 19.6, 14.5, and 7.7 GeV, Cu+Cu collisions at √sNN=200 and 62.4 GeV, Cu+Au collisions at √sNN=200 GeV, U+U collisions at√sNN=193 GeV, d+Au collisions at √sNN=200 GeV, He3+Au collisions at √sNN=200 GeV, and p+p collisions at √sNN=200 GeV. We present centrality-dependent distributions at midrapidity in terms of the number of nucleon participants, Npart, and the number of constituent quark participants, Nqp. For all A+A collisions down to √sNN=7.7 GeV, we observed that the midrapidity data are better described by scaling with Nqp than scaling with Npart. Finally, our estimates of the Bjorken energy density, [epsilon]BJ, and the ratio of dET/d[eta] to dNch/d[eta] are presented, the latter of which is seen to be constant as a function of centrality for all systems.

These proceedings gather invited and contributed talks presented at the XXII DAE-BRNS High Energy Physics (HEP) Symposium, which was held at the University of Delhi, India, on 12–16 December 2016. The contributions cover a variety of topics in particle physics, astroparticle physics, cosmology and related areas from both experimental and theoretical perspectives, namely (1) Neutrino Physics, (2) Standard Model Physics (including Electroweak, Flavour Physics), (3) Beyond Standard Model Physics, (4) Heavy Ion Physics & QCD (Quantum Chromodynamics), (5) Particle Astrophysics & Cosmology, (6) Future Experiments and Detector Development, (7) Formal Theory, and (8) Societal Applications: Medical Physics, Imaging, etc. The DAE-BRNS High Energy Physics Symposium, widely considered to be one of the leading symposiums in the field of Elementary Particle Physics, is held every other year in India and supported by the Board of Research in Nuclear Sciences (BRNS), Department of Atomic Energy (DAE), India. As many as 400 physicists and researchers attended the 22nd Symposium to discuss the latest advances in the field. A poster session was also organized to highlight the work and findings of young researchers. Bringing together the essential content, the book offers a valuable resource for both beginning and advanced researchers in the field.