Puzzles in Cabibbo-Suppressed Charm Decays

We identify two Cabibbo suppressed $D^+$ decay modes with anomalously high branching ratios which are not simply explained by any model. All standard model diagrams that can contribute to these decays are related by symmetries to diagrams for other decays that do not show any such enhancement. If these high branching ratios are confirmed by more precise experiments, they may require new physics to explain them. Anomalies in $D_s$ decays and tests for possible violation of G-parity are discussed.Comment: 12 pages, additional clarification at eq. (13), correction of error in eq. (18) and subsequent discussio

Radiative decays: a new flavour filter

Radiative decays of the $1^3D_1$ orbital excitations of the $\rho$, $\omega$ and $\phi$ to the scalars $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$ are shown to provide a flavour filter, clarifying the extent of glueball mixing in the scalar states. A complementary approach to the latter is provided by the radiative decays of the scalar mesons to the ground-state vectors $\rho$, $\omega$ and $\phi$. Discrimination among different mixing scenarios is strong.Comment: 12 pages, 1 table, 0 figure

Spaces for smoking in a psychiatric hospital: social capital, resistance to control, and significance for 'therapeutic landscapes'

This paper reports on research framed by theories of therapeutic landscapes and the ways that the social, physical and symbolic dimensions of landscapes relate to wellbeing and healing. We focus especially on the question of how attributes of therapeutic landscapes are constructed in different ways according to the variable perspectives of individuals and groups. Through an ethnographic case study in a psychiatric hospital in the North of England we explore the perceived significance for wellbeing of ‘smoking spaces’ (where tobacco smoking is practiced in ways that may, or may not be officially sanctioned). We interpret our findings in light of literature on how smoking spaces are linked to the socio-geographical power relations that determine how smoking is organised within the hospital and how this is understood by different groups using the hospital building. We draw on qualitative research findings from discussion groups, observations, and interviews with patients, carers and staff. These focused on their views about the building design and setting of the new psychiatric hospital in relation to their wellbeing, and issues relating to smoking spaces emerged as important for many participants. Creating and managing smoking spaces as a public health measure in psychiatric hospitals is shown to be a controversial issue involving conflicting aims for health and wellbeing of patients and staff. Our findings indicate that although from a physical health perspective, smoking is detrimental, the spaces in which patients and staff smoke have social and psychological significance, providing a forum for the creation of social capital and resistance to institutional control. While the findings relate to one case study setting, the paper illustrates issues of wider relevance and contributes to an international literature concerning the tensions between perceived psychological and psychosocial benefits of smoking vs. physical harm that smoking is likely to cause. We consider the implications for hospital design and the model of care

'Therapeutic landscapes' and the importance of nostalgia, solastalgia, salvage and abandonment for psychiatric hospital design

We examine emotional reactions to changes to medical spaces of care, linked with past experiences. In this paper we draw on findings from a qualitative study of the transfer of psychiatric inpatient care from an old to a newly built facility. We show how the meanings attributed to ‘therapeutic landscapes’ from one׳s past can evoke emotions and memories, manifesting in ideas about nostalgia, solastalgia, salvage and abandonment, which can impinge on one׳s present therapeutic experience. We reflect on how consideration of these ideas might contribute to better future design of psychiatric inpatient facilities and the wellbeing of those using them

Selection rules for J^PC Exotic Hybrid Meson Decay in Large-N_c

The coupling of a neutral hybrid {1,3,5...}^-+ exotic particle (or current) to two neutral (hybrid) meson particles with the same J^PC and J=0 is proved to be sub-leading to the usual large-N_c QCD counting. The coupling of the same exotic particle to certain two - (hybrid) meson currents with the same J^PC and J=0 is also sub-leading. The decay of a {1,3,5...}^-+ hybrid to eta pi^0, eta' pi^0, eta' eta, eta(1295) pi^0, pi(1300)^0 pi0, eta(1440) pi^0, a_0(980)^0 sigma or f_0(980) sigma is sub-leading, assuming that these final state particles are (hybrid) mesons in the limit of large N_c.Comment: 16 pages, LaTeX. Main paper shortened/rewritten and appendices expanded. Implications for phenomenology of exotic hybrid mesons clarifie

Radiative Scalar Meson Decays in the Light-Front Quark Model

We construct a relativistic $^3P_0$ wavefunction for scalar mesons within the framework of light-front quark model(LFQM). This scalar wavefunction is used to perform relativistic calculations of absolute widths for the radiative decay processes$(0^{++})\to\gamma\gamma,(0^{++})\to\phi\gamma$, and $(0^{++})\to\rho\gamma$ which incorporate the effects of glueball-$q\bar{q}$ mixing. The mixed physical states are assumed to be $f_0(1370),f_0(1500)$,and $f_0(1710)$ for which the flavor-glue content is taken from the mixing calculations of other works. Since experimental data for these processes are poor, our results are compared with those of a recent non-relativistic model calculation. We find that while the relativistic corrections introduced by the LFQM reduce the magnitudes of the decay widths by 50-70%, the relative strengths between different decay processes are fairly well preserved. We also calculate decay widths for the processes $\phi\to(0^{++})\gamma$ and (0^{++})\to\gamma\gamm involving the light scalars $f_0(980)$ and $a_0(980)$ to test the simple $q\bar{q}$ model of these mesons. Our results of $q\bar{q}$ model for these processes are not quite consistent with well-established data, further supporting the idea that $f_0(980)$ and $a_0(980)$ are not conventional $q\bar{q}$ states.Comment: 10 pages, 4 figure

Strong Decays of Strange Quarkonia

In this paper we evaluate strong decay amplitudes and partial widths of strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give numerical results for all energetically allowed open-flavor two-body decay modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and 1F multiplets, comprising strong decays of a total of 43 resonances into 525 two-body modes, with 891 numerically evaluated amplitudes. This set of resonances includes all strange qqbar states with allowed strong decays expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic quark model SHO wavefunctions to evaluate these amplitudes, and quote numerical results for all amplitudes present in each decay mode. We also discuss the status of the associated experimental candidates, and note which states and decay modes would be especially interesting for future experimental study at hadronic, e+e- and photoproduction facilities. These results should also be useful in distinguishing conventional quark model mesons from exotica such as glueballs and hybrids through their strong decays.Comment: 69 pages, 5 figures, 39 table

Axial vector form factor of nucleons in a light-cone diquark model

The nucleon axial vector form factor is investigated in a light-cone quark spectator diquark model, in which Melosh rotations are applied to both the quark and vector diquark. It is found that this model gives a very good description of available experimental data and the results have very little dependence on the parameters of the model. The relation between the nucleon axial constant and the anomalous magnetic moment of nucleons is also discussed.Comment: 8 pages, Revtex4, 1 figure, version to be published in Phys. Rev.

The Proton Spin and the Wigner Rotation

It is shown that in both the gluonic and strange sea explanations of the Ellis-Jaffe sum rule violation discovered by the European Muon Collaboration (EMC), the spin of the proton, when viewed in in its rest reference frame, could by fully provided by quarks and antiquarks within a simple quark model picture, taken into account the relativistic effect from the Wigner rotation.Comment: 13 latex page

Online administration of research-based assessments

Research-based assessments (RBAs; e.g., the Force Concept Inventory) that measure student content knowledge, attitudes, or identities have played a major role in transforming physics teaching practices. RBAs offer instructors a standardized method for empirically investigating the efficacy of their instructional practices and documenting the impacts of course transformations. Unlike course exams, the common usage of standardized RBAs across institutions uniquely supports instructors to compare their student outcomes over time or against multi-institutional data sets. While the number of RBAs and RBA-using instructors has increased over the last three decades, barriers to administering RBAs keep many physics instructors from using them.1,2 To mitigate these barriers, we have created full-service online RBA platforms (i.e., the Learning About STEM Student Outcomes [LASSO],3 Colorado Learning Attitudes About Science Survey for Experimental Physics [E-CLASS],4 and Physics Lab Inventory of Critical thinking [PLIC]5 platforms) that host, administer, score, and analyze RBAs. These web-based platforms can make it easier for instructors to use RBAs, especially as many courses have been forced to transition to online instruction.This article is published as Ben Van Dusen, Mollee Shultz, Jayson M. Nissen, Bethany R. Wilcox, N. G. Holmes, Manher Jariwala, Eleanor W. Close, H. J. Lewandowski, Steven Pollock; Online administration of research-based assessments. Am. J. Phys. 1 January 2021; 89 (1): 7–8. https://doi.org/10.1119/10.0002888. Posted with permission