T. M. Larsen

Bio: T. M. Larsen is an academic researcher from University of Copenhagen. The author has contributed to research in topics: Rapidity & Pion. The author has an hindex of 6, co-authored 8 publications receiving 2120 citations. Previous affiliations of T. M. Larsen include University of Oslo.

Pseudorapidity distributions of charged particles from Au+Au collisions at the maximum RHIC energy

Abstract: We present charged-particle multiplicities as a function of pseudorapidity and collision centrality for the ${}^{197}\mathrm{Au}{+}^{197}\mathrm{Au}$ reaction at $\sqrt{{s}_{\mathrm{NN}}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}200\mathrm{GeV}$. For the $5%$ most central events we obtain ${\mathrm{dN}}_{\mathrm{ch}}/d\ensuremath{\eta}{|}_{\ensuremath{\eta}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}625\ifmmode\pm\else\textpm\fi{}55$ and ${N}_{\mathrm{ch}}{|}_{\ensuremath{-}4.7\ensuremath{\le}\ensuremath{\eta}\ensuremath{\le}4.7}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}4630\ifmmode\pm\else\textpm\fi{}370$, i.e., $14%$ and $21%$ increases, respectively, relative to $\sqrt{{s}_{\mathrm{NN}}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}130\mathrm{GeV}$ collisions. Charged-particle production per pair of participant nucleons is found to increase from peripheral to central collisions around midrapidity. These results constrain current models of particle production at the highest RHIC energy.

Single-transverse-spin asymmetries of identified charged hadrons in polarized pp collisions at sqrt[s]=62.4 GeV.

Abstract: The first measurements of $x_F$-dependent single spin asymmetries of identified charged hadrons, $\pi^{\pm}$, $K^{\pm}$, and protons, from transversely polarized proton-proton collisions at 62.4 GeV at RHIC are presented. The measurements extend to high-$x_F$ ($|x_F|\sim 0.6$) in both the forward and backward directions.Large asymmetries are seen in the pion and kaon channels. The asymmetries in inclusive $\pi^{+}$ production, $A_N(\pi^+)$, increase with $x_F$ from 0 to $\sim$0.25 %at $x_F = 0.6$ and $A_N(\pi^{-})$ decrease from 0 to $\sim$$-$0.4. Even though $K^-$ contains no valence quarks, observed asymmetries for $K^-$ unexpectedly show positive values similar to those for $K^+$, increasing with $x_F$, whereas proton asymmetries are consistent with zero over the measured kinematic range. Comparisons of the data with predictions of QCD-based models are presented. The flavor dependent single spin asymmetry measurements of identified hadrons allow for stringent tests of theoretical models of partonic dynamics in the RHIC energy regime.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Glauber Modeling in High Energy Nuclear Collisions

Abstract: We review the theoretical background, experimental techniques, and phenomenology of what is known in relativistic heavy ion physics as the Glauber model, which is used to calculate geometric quantities. A brief history of the original Glauber model is presented, with emphasis on its development into the purely classical, geometric picture used for present-day data analyses. Distinctions are made between the optical limit and Monte Carlo approaches, which are often used interchangeably but have some essential differences in particular contexts. The methods used by the four RHIC experiments are compared and contrasted, although the end results are reassuringly similar for the various geometric observables. Finally, several important RHIC measurements are highlighted that rely on geometric quantities, estimated from Glauber calculations, to draw insight from experimental observables. The status and future of Glauber modeling in the next generation of heavy ion physics studies is briefly discussed.

Electron-Ion Collider: The next QCD frontier: Understanding the glue that binds us all

Abstract: This White Paper presents the science case of an Electron-Ion Collider (EIC), focused on the structure and interactions of gluon-dominated matter, with the intent to articulate it to the broader nuclear science community. It was commissioned by the managements of Brookhaven National Laboratory (BNL) and Thomas Jefferson National Accelerator Facility (JLab) with the objective of presenting a summary of scientific opportunities and goals of the EIC as a follow-up to the 2007 NSAC Long Range plan. This document is a culmination of a community-wide effort in nuclear science following a series of workshops on EIC physics over the past decades and, in particular, the focused ten-week program on “Gluons and quark sea at high energies” at the Institute for Nuclear Theory in Fall 2010. It contains a brief description of a few golden physics measurements along with accelerator and detector concepts required to achieve them. It has been benefited profoundly from inputs by the users’ communities of BNL and JLab. This White Paper offers the promise to propel the QCD science program in the US, established with the CEBAF accelerator at JLab and the RHIC collider at BNL, to the next QCD frontier.