MCPLOTS: a particle physics resource based on volunteer computing

The mcplots.cern.ch web site (MCPLOTS) provides a simple online repository of plots made with high-energy-physics event generators, comparing them to a wide variety of experimental data. The repository is based on the HEPDATA online database of experimental results and on the RIVET Monte Carlo analysis tool. The repository is continually updated and relies on computing power donated by volunteers, via the LHC@HOME platform.Comment: 30 page

Nonclassical Moments and their Measurement

Practically applicable criteria for the nonclassicality of quantum states are formulated in terms of different types of moments. For this purpose the moments of the creation and annihilation operators, of two quadratures, and of a quadrature and the photon number operator turn out to be useful. It is shown that all the required moments can be determined by homodyne correlation measurements. An example of a nonclassical effect that is easily characterized by our methods is amplitude-squared squeezing.Comment: 12 pages, 6 figure

First-Order Type Effects in YBa2_2Cu3_3O6+x_{6+x} at the Onset of Superconductivity

We present results of Raman scattering experiments on tetragonal ${\rm (Y_{1-y}Ca_{y})Ba_{2}Cu_{3}O_{6+x}}$ for doping levels $p(x,y)$ between 0 and 0.07 holes/CuO$_2$. Below the onset of superconductivity at $p_{\rm sc1} \approx 0.06$, we find evidence of a diagonal superstructure. At $p_{\rm sc1}$, lattice and electron dynamics change discontinuously with the charge and spin properties being renormalized at all energy scales. The results indicate that charge ordering is intimately related to the transition at $p_{\rm sc1}$ and that the maximal transition temperature to superconductivity at optimal doping $T_{c}^{\rm max}$ depends on the type of ordering at $p>p_{\rm sc1}$.Comment: 4 pages, 4 figure

A study of multi-jet production in association with an electroweak vector boson

Abstract: We consider the production of a single Z or W boson in association with jets at the LHC. We compute the corresponding cross sections by matching NLO QCD predictions with the Herwig++ and Pythia8 parton showers, and by merging all of the underlying matrix elements with up to two light partons at the Born level. We compare our results with several 7-TeV measurements by the ATLAS and CMS collaborations, and overall we find a good agreement between theory and data

Brief of Amici Curiae Public Justice, the Prisoners’ Rights Project of the Legal Aid Society of the City of New York, and the Pennsylvania Institutional Law Project in Support of Plaintiffs-Appellees (Argueta v. United States Immigration and Customs Enforcement)

Public Justice is a national public interest law firm dedicated to preserving access to justice, remedying government and corporate wrongdoing, and holding the powerful accountable in courts. As part of its access-to-justice work, Public Justice created an Iqbal Project in 2009 to combat misuse of the Supreme Court’s decision in Ashcroft v. Iqbal, 129 S. Ct. 1937 (2009). The Project tracks developments in the case law and provides assistance to counsel facing Iqbal-based motions. Public Justice is concerned that overbroad readings of Iqbal threaten to deny justice to many injured plaintiffs with meritorious claims. In addition to Public Justice’s Iqbal-related interest in this case, the firm also represents prisoners, arrestees, other detainees, their family members, and other plaintiffs in a variety of cases involving constitutional claims. See, e.g., Hui v. Castaneda, 130 S. Ct. 1845 (2010); Dillon v. Rogers, 596 F.3d 260 (5th Cir. 2010); Menotti v. City of Seattle, 409 F.3d 1113 (9th Cir. 2005); Everett v. Cherry, No. 08-00622 (E.D. Va.) (case pending). Public Justice is concerned that Appellants’ arguments regarding supervisory liability will, if accepted, prevent many plaintiffs with constitutional claims from obtaining a full remedy. The Legal Aid Society of the City of New York is a private organization that has provided free legal assistance to indigent persons in New York City for over 125 years. Through its Prisoners’ Rights Project, the Society seeks to ensure that 2 prisoners’ constitutional and statutory rights are protected. The Society advocates on behalf of prisoners in the New York City jails and New York state prisons, and conducts litigation on prison conditions. The Society often litigates claims of supervisory liability. The Pennsylvania Institutional Law Project is a private not-for-profit organization created to ensure equal access to justice for indigent institutionalized persons. Part of the Pennsylvania Legal Aid Network, the Institutional Law Project provides direct representation services, self-help and other legal materials, and class representation to eligible low-income residents of Pennsylvania’s prisons, jails, state hospitals, and state centers. The Project also takes part in advocacy and legislative initiatives concerning institutional reform in Pennsylvania

Electron interactions and charge ordering in La2−x_{2-x}Srx_xCuO4_4

We present results of inelastic light scattering experiments on single-crystalline La$_{2-x}$Sr$_{x}$CuO$_4$ in the doping range $0.00 \le x=p \le 0.30$ and Tl$_2$Ba$_2$CuO$_{6+\delta}$ at $p=0.20$ and $p=0.24$. The main emphasis is placed on the response of electronic excitations in the antiferromagnetic phase, in the pseudogap range, in the superconducting state, and in the essentially normal metallic state at $x \ge 0.26$, where no superconductivity could be observed. In most of the cases we compare B$_{1g}$ and B$_{2g}$ spectra which project out electronic properties close to $(\pi,0)$ and $(\pi/2, \pi/2)$, respectively. In the channel of electron-hole excitations we find universal behavior in B$_{2g}$ symmetry as long as the material exhibits superconductivity at low temperature. In contrast, there is a strong doping dependence in B$_{1g}$ symmetry: (i) In the doping range $0.20 \le p \le 0.25$ we observe rapid changes of shape and temperature dependence of the spectra. (ii) In La$_{2-x}$Sr$_{x}$CuO$_4$ new structures appear for $x < 0.13$ which are superposed on the electron-hole continuum. The temperature dependence as well as model calculations support an interpretation in terms of charge-ordering fluctuations. For $x \le 0.05$ the response from fluctuations disappears at B$_{1g}$ and appears at B$_{2g}$ symmetry in full agreement with the orientation change of stripes found by neutron scattering. While, with a grain of salt, the particle-hole continuum is universal for all cuprates the response from fluctuating charge order in the range $0.05 \le p < 0.16$ is so far found only in La$_{2-x}$Sr$_{x}$CuO$_4$. We conclude that La$_{2-x}$Sr$_{x}$CuO$_4$ is close to static charge order and, for this reason, may have a suppressed $T_c$.Comment: 17 pages, 15 figure