Discretising the velocity distribution for directional dark matter experiments

Dark matter (DM) direct detection experiments which are directionally-sensitive may be the only method of probing the full velocity distribution function (VDF) of the Galactic DM halo. We present an angular basis for the DM VDF which can be used to parametrise the distribution in order to mitigate astrophysical uncertainties in future directional experiments and extract information about the DM halo. This basis consists of discretising the VDF in a series of angular bins, with the VDF being only a function of the DM speed $v$ within each bin. In contrast to other methods, such as spherical harmonic expansions, the use of this basis allows us to guarantee that the resulting VDF is everywhere positive and therefore physical. We present a recipe for calculating the event rates corresponding to the discrete VDF for an arbitrary number of angular bins $N$ and investigate the discretisation error which is introduced in this way. For smooth, Standard Halo Model-like distribution functions, only $N=3$ angular bins are required to achieve an accuracy of around $10-30\%$ in the number of events in each bin. Shortly after confirmation of the DM origin of the signal with around 50 events, this accuracy should be sufficient to allow the discretised velocity distribution to be employed reliably. For more extreme VDFs (such as streams), the discretisation error is typically much larger, but can be improved with increasing $N$. This method paves the way towards an astrophysics-independent analysis framework for the directional detection of dark matter.Comment: 36 pages, 11 figures. Matches version accepted in JCAP. Python code for Radon transform calculation available from the autho

Earth-Scattering of super-heavy Dark Matter: updated constraints from detectors old and new

Direct searches for Dark Matter (DM) are continuously improving, probing down to lower and lower DM-nucleon interaction cross sections. For strongly-interacting massive particle (SIMP) Dark Matter, however, the accessible cross section is bounded from above due to the stopping effect of the atmosphere, Earth and detector shielding. We present a careful calculation of the SIMP signal rate, focusing on super-heavy DM ($m_\chi \gtrsim 10^5 \,\,\mathrm{GeV}$) for which the standard nuclear-stopping formalism is applicable, and provide code for implementing this calculation numerically. With recent results from the low-threshold CRESST 2017 surface run, we improve the maximum cross section reach of direct detection searches by a factor of around 5000, for DM masses up to $10^8 \,\,\mathrm{GeV}$. A reanalysis of the longer-exposure, sub-surface CDMS-I results (published in 2002) improves the previous cross section reach by two orders of magnitude, for masses up to $10^{15} \,\,\mathrm{GeV}$. Along with complementary constraints from SIMP capture and annihilation in the Earth and Sun, these improved limits from direct nuclear scattering searches close a number of windows in the SIMP parameter space in the mass range $10^6$ GeV to $10^{13}$ GeV, of particular interest for heavy DM produced gravitationally at the end of inflation.Comment: 12 pages, 7 figures. Code available at https://github.com/bradkav/verne . Comments welcome. v2: Fixed references and minor typos, corrected "$\nu$-cleus" to "CRESST 2017 surface run". v3: Added Appendix A with explicit expressions and coordinate system. v4: Added discussion of variance in final DM speed. Version published in PR

Re-examining the significance of the 750 GeV diphoton excess at ATLAS

The excess seen in the diphoton channel at around 750 GeV by both ATLAS and CMS has caused a great deal of excitement in the particle physics community. However, there has recently been much discussion about uncertainties in the significance of the peak seen by the ATLAS experiment. In this note, we aim to estimate this significance using a range of possible parametrisations for the smooth diphoton background. We obtain a local significance close to that reported by ATLAS and further demonstrate that the significance of the excess is not substantially reduced when more complicated background functions are considered. In particular, the background contribution is strongly constrained by the small numbers of events at large diphoton invariant mass. Future data releases will improve constraints on the diphoton background, as well as clarifying the true nature of the 750 GeV excess.Comment: 6 pages, 2 figures. Code available at https://github.com/bradkav/ATLASfits/releases/latest . Additional references and discussion on impact of using binned data added in v3. Comments very welcom

The Effect of Motivational Highlight DVDs on State Self‐Confidence in Elite Female Hockey Players

Recent technological developments in applied sport psychology utilising video-taping and playback techniques to enhance athletic performance have become increasingly attractive to coaches, athletes, and sport psychologists (Ives et al., 2002: Journal of Applied S84 Abstracts Downloaded By: [Bournemouth University] At: 12:29 15 October 2009 Sport Psychology, 14, 237 – 245). This study aimed to examine the effectiveness of two types of highlight peak performance digital versatile discs (DVDs); peer-modelling and self-modelling, on state selfconfidence of elite female hockey players. It further addressed the issue of whether the experience of watching yourself versus observing peers differentially affects state self-confidence. The volunteer participants comprised 15 members of a female National League hockey squad located in the South of England (mean age 24.53, s¼4.94). DVDs incorporating highlight play were supplemented with inspirational music and viewed by the athletes at two stages in the competitive season (midseason and end of season). At both stages, the athletes were exposed to a peer modelling, selfmodelling, and control video during separate testing sessions. Athletes completed the State Sport- Confidence Inventory (Vealey, 1986: Journal of Sport Psychology, 8, 221 – 246) prior to and after viewing the highlight DVDs. The data were subjected to two 362 RM ANOVAs to determine if the self-modelling, peer-modelling, and control DVDs affected state self-confidence. An RM ANOVA was performed on data collected at the two stages of the competitive season. To determine the nature of change in state self-confidence in relation to type of DVD watched follow-up univariate ANOVAs were carried out on the dataset. Semi-structured interviews were also conducted to explore participants’ perceptions of how the intervention affected their cognition, affect, and behaviour. Interviews were transcribed ad verbatim and analysed using inductive content analysis. Findings support and further encourage the use of motivational highlight DVDs in sport. Both the self-modelling and peer-modelling DVDs had a significant (P50.01) effect on state self-confidence at both stages in the competitive season. No differences were found between the effects of the self-modelling and peer-modelling DVDs during the mid season testing phase. At the end of season testing phase, the self modelling DVD proved to be superior in enhancing state self-confidence. This finding was supported through the results of the qualitative analysis. The results of this study provide empirical support for the use of motivational highlight DVDs as a pre-performance strategy in athletic situations

Tests of the elaborated intrusion theory of craving and desire: Features of alcohol craving during treatment for an alcohol disorder

PubMed ID: 1936444

The Elaborated Intrusion Theory of Desire: A 10-year retrospective and implications for addiction treatments

Ten years after the publication of Elaborated Intrusion (EI) Theory, there is now substantial research into its key predictions. The distinction between intrusive thoughts, which are driven by automatic processes, and their elaboration, involving controlled processing, is well established. Desires for both addictive substances and other desired targets are typically marked by imagery, especially when they are intense. Attention training strategies such as body scanning reduce intrusive thoughts, while concurrent tasks that introduce competing sensory information interfere with elaboration, especially if they compete for the same limited-capacity working memory resources. EI Theory has spawned new assessment instruments that are performing strongly and offer the ability to more clearly delineate craving from correlated processes. It has also inspired new approaches to treatment. In particular, training people to use vivid sensory imagery for functional goals holds promise as an intervention for substance misuse, since it is likely to both sustain motivation and moderate craving

Effects of visuospatial tasks on desensitization to emotive memories

Objectives: Vivid and intrusive memories of extreme trauma can disrupt a stepwise approach to imaginal exposure. Concurrent tasks that load the visuo-spatial sketchpad (VSSP) of working memory reduce memory vividness during imaginal exposure. Such tasks may help maintain a progressive exposure protocol while minimizing distress during treatment. The current study tested whether relief of distress from a competing VSSP load during emotive imagery is at the cost of impaired desensitization. Design: This study examined repeated exposure to emotive memories using 18 unselected undergraduates, using a within-subjects design. Method: Participants recalled three positive and three negative self-related memories, and rated the vividness and emotiveness of the image. Participants then received all three conditions (Eye Movements; Visual Noise; Control) in a counterbalanced order. One positive and one negative recollection were used for each condition. They then rated the vividness of the image and their emotional response before proceeding to the next trial. There were 8 trials for each image. At a noninterference session one week later, participants recalled each image, rating its vividness and their emotional response. Results: Consistent with previous research, vividness and distress during imaging were lower during eye movements than in exposure alone, with passive visual interference giving intermediate results. A small reduction in emotional responses a week later was of similar size for the three conditions

Visuospatial tasks suppress craving for cigarettes.

The Elaborated Intrusion (EI) theory of desire posits that visual imagery plays a key role in craving. We report a series of experiments testing this hypothesis in a drug addiction context. Experiment 1 showed that a mental visual imagery task with neutral content reduced cigarette craving in abstaining smokers, but that an equivalent auditory task did not. The effect of visual imagery was replicated in Experiment 2, which also showed comparable effects of non-imagery visual working memory interference. Experiment 3 showed that the benefit of visual over auditory interference was not dependent upon imagery being used to induce craving. Experiment 4 compared a visuomotor task, making shapes from modeling clay, with a verbal task (counting back from 100), and again showed a benefit of the visual over the non-visual task. We conclude that visual imagery supports craving for cigarettes. Competing imagery or visual working memory tasks may help tackle craving in smokers trying to quit