Isolated Photons in Deep Inelastic Scattering

Photon radiation at large transverse momenta at colliders is a detailed probe of hard interaction dynamics. The isolated photon production cross section in deep inelastic scattering was measured recently by the ZEUS experiment, and found to be considerably larger than theoretical predictions obtained with widely used event generators. To investigate this discrepancy, we perform a dedicated parton-level calculation of this observable, including contributions from fragmentation and large-angle radiation. Our results are in good agreement with all aspects of the experimental measurement.Comment: 4 pages, 3 figure

COMPELLED SPEECH—CONNECTICUT AND MASSACHUSETTS: INADVERTENTLY INVITING SUPPRESSION OF DISSENT POLITICAL EXPRESSION

People often argue that transparency in a democracy is imperative. Transparency, though, may only be achieved through disclosure. In recent years, the United States Supreme Court has strongly favored compelled disclosure in the context of political expression. Yet, there exists an exception to this mandate for minor, dissident political parties. This exception, established in Buckley v. Valeo, 424 U.S. 1, 74 (1976) (per curiam), purports to shield those parties from threats, harassment, and reprisals due to their minority status. Historically this exception has been narrowly utilized to protect Cold War era socialist political parties. This Note argues that the Buckley minor-party exception should be extended to not only encompass minor, partisan political parties, but also issue-based minority groups and their members. This Note will further argue that issue-oriented expression through association deserves the same First Amendment protection as direct advocacy; that association by membership deserves greater protection than association through monetary support; and that association by membership is as strong as, and therefore deserves the same degree of protection, as direct expression. Absent such extension of the Buckley minor-party exception, recent legislation enacted by Connecticut and Massachusetts, is susceptible to a constitutional challenge by issue-oriented minority groups and their members who are subject to mandatory disclosure of personal information

COMPELLED SPEECH—CONNECTICUT AND MASSACHUSETTS: INADVERTENTLY INVITING SUPPRESSION OF DISSENT POLITICAL EXPRESSION

People often argue that transparency in a democracy is imperative. Transparency, though, may only be achieved through disclosure. In recent years, the United States Supreme Court has strongly favored compelled disclosure in the context of political expression. Yet, there exists an exception to this mandate for minor, dissident political parties. This exception, established in Buckley v. Valeo, 424 U.S. 1, 74 (1976) (per curiam), purports to shield those parties from threats, harassment, and reprisals due to their minority status. Historically this exception has been narrowly utilized to protect Cold War era socialist political parties. This Note argues that the Buckley minor-party exception should be extended to not only encompass minor, partisan political parties, but also issue-based minority groups and their members. This Note will further argue that issue-oriented expression through association deserves the same First Amendment protection as direct advocacy; that association by membership deserves greater protection than association through monetary support; and that association by membership is as strong as, and therefore deserves the same degree of protection, as direct expression. Absent such extension of the Buckley minor-party exception, recent legislation enacted by Connecticut and Massachusetts, is susceptible to a constitutional challenge by issue-oriented minority groups and their members who are subject to mandatory disclosure of personal information

Characteristics of Cherenkov Radiation in Naturally Occuring Ice

We revisit the theory of Cherenkov radiation in uniaxial crystals. Historically, a number of flawed attempts have been made at explaining this radiation phenomenon and a consistent error-free description is nowhere available. We apply our calculation to a large modern day telescope - IceCube. Being located at the Antarctica, this detector makes use of the naturally occuring ice as a medium to generate Cherenkov radiation. However, due to the high pressure at the depth of the detector site, large volumes of hexagonal ice crystals are formed. We calculate how this affects the Cherenkov radiation yield and angular dependence. We conclude that the effect is small, at most about a percent, and would only be relevant in future high precision instruments like e.g. Precision IceCube Next Generation Upgrade (PINGU). For radio-Cherenkov experiments which use the presence of a clear Cherenkov cone to determine the arrival direction, any variation in emission angle will directly and linearly translate into a change in apparent neutrino direction. In closing, we also describe a simple experiment to test this formalism, and calculate the impact of anisotropy on light-yields from lead tungstate crystals as used, for example, in the CMS calorimeter at the CERN LHC

A computationally universal phase of quantum matter

We provide the first example of a symmetry protected quantum phase that has universal computational power. Throughout this phase, which lives in spatial dimension two, the ground state is a universal resource for measurement based quantum computation.Comment: 5 + 2 page

Neural mechanisms of resistance to peer influence in early adolescence

During the shift from a parent-dependent child to a fully autonomous adult, peers take on a significant role in shaping the adolescent’s behaviour. Peer-derived influences are not always positive, however. Here we explore neural correlates of inter-individual differences in the probability of resisting peer influence in early adolescence. Using functional magnetic-resonance imaging (fMRI), we found striking differences between 10-year old children with high and low resistance to peer influence in their brain activity during observation of angry hand-movements and angry facial expressions: compared with subjects with low resistance to peer influence, individuals with high resistance showed a highly coordinated brain activity in neural systems underlying perception of action and decision making. These findings suggest that the probability of resisting peer influence depends on neural interactions during observation of emotion-laden actions