The charm quark mass with dynamical fermions

We compute the charm quark mass in lattice QCD and compare different formulations of the heavy quark, and quenched data to that with dynamical sea quarks. We take the continuum limit of the quenched data by extrapolating from three different lattice spacings, and compare to data with two flavours of dynamical sea quarks with a mass around the strange at the coarsest lattice spacing. Both the FNAL and ALPHA formalism are used. We find the different heavy quark formulations have the same continuum limit in the quenched approximation, and limited evidence that this approximation overestimates the charm quark mass.Comment: Lattice2004(heavy) 3 pages, 2 figure

The effect of sea quarks on the mass of the charm quark from Lattice QCD

We compute the mass of the charm quark using both quenched and dynamical lattice QCD calculations. We examine the effects of mass dependent lattice artifacts by comparing two different formalisms for the heavy quarks. We take the continuum limit of the charm mass in quenched QCD by extrapolating from three different lattice spacings. At a fixed lattice spacing, the mass of the charm quark is compared between quenched QCD and dynamical QCD with a sea quark mass around strange. In the continuum limit of quenched QCD, we find m_c(m_c)=1.29(7)(13) GeV. No evidence was seen for unquenching.Comment: Added NP analysis of quenched data, corrected error in PCAC RGI mass, updated strange quark mass discussion and references, unified notation and corrected typos. No change in final result. Version accepted for publication in JHE

Staggered Chiral Perturbation Theory for Heavy-Light Mesons

We incorporate heavy-light mesons into staggered chiral perturbation theory, working to leading order in 1/m_Q, where m_Q is the heavy quark mass. At first non-trivial order in the chiral expansion, staggered taste violations affect the chiral logarithms for heavy-light quantities only through the light meson propagators in loops. There are also new analytic contributions coming from additional terms in the Lagrangian involving heavy-light and light mesons. Using this heavy-light staggered chiral perturbation theory, we perform the one-loop calculation of the B (or D) meson leptonic decay constant in the partially quenched and full QCD cases. In our treatment, we assume the validity both of the "fourth root trick" to reduce four staggered tastes to one, and of the prescription to represent this trick in the chiral theory by insertions of factors of 1/4 for each sea quark loop.Comment: 48 pages, 6 figures. v3: Some clarifying comments/caveats added; typos fixed. Corresponds to published versio

Response to mental health calls: The frontline perspectives of police officers, communicators and administrators

Abstract OBJECTIVES: The purpose of this study was to examine the lived experiences of frontline police personnel of a mid-sized police service in Southern Ontario. As the prevalence of mental illness increases, so do the calls for assistance to police services. Police officers often find themselves on the frontline and are often the first responders to mental health calls when an individual is in crisis (Wells & Schafer, 2006). With the majority of current research being quantitative in nature, this qualitative study allowed the voice of frontline police personnel to be heard in order to provide a complete picture of police response to mental health calls for service. Furthermore, this study included communications personnel, which are an important group that has often been overlooked in previous studies, but are instrumental in police response to all calls for service. METHODS: The lived experiences of fourteen participants were examined using in-depth, semi-structured interviews with heuristic phenomenology as a guiding theoretical orientation. The participants were placed into one of three groups based on his/her current role within the police service with the total number of participants within the groups as follows: police officers (n = 7), administrators (n = 3) and communicators (n = 4). Four research questions were examined through fifteen interview questions. RESULTS: Upon detailed analysis of the interviews, several themes and subthemes emerged from the data across all groups of participants. Each theme was found to play an important role in in responding to mental health calls. The themes included: (1) Interaction of roles on mental health calls; (2) Challenges relating to mental health calls; (3) Strategies for responding to mental health calls; and (4) Coping and aftermath. Four subthemes emerged relating to challenges when responding to mental health calls: (i) Perceived increase in mental health calls for service; (ii) Lack of training; (iii) Type of training; (iv) The broken system. CONCLUSIONS: Officers and communicators often find themselves as the first responders to individuals suffering from a mental illness who are in crisis. Hopefully this study has created an increased awareness of the role that frontline police personnel play when responding to mental health calls for service, some of the challenges that they face, and their voices will continue to be heard as policy makers and stakeholders make improvements and adjustments to the current system in the future

The mass of the charm quark from unquenched lattice QCD at fixed lattice spacing

We determine the mass of the charm quark ($m_c$) from lattice QCD with two flavors of dynamical quarks with a mass around the strange quark. We compare this to a determination in quenched QCD which has the same lattice spacing (0.1 fm). We investigate different formulations of the quark mass, based on the Vector Ward Identity, PCAC relation and the FNAL heavy quark formalism. Based on these preliminary results we find no effects due to sea quarks with a mass around strange.Comment: Presented at 21st International Symposium on Lattice Field Theory (LATTICE 2003), Tsukuba, Japan, 15-19 July, 200

The second moment of the pion's distribution amplitude

We present preliminary results for the second moment of the pion's distribution amplitude. The lattice formulation and the phenomenological implications are briefly reviewed, with special emphasis on some subtleties that arise when the Lorentz group is replaced by the hypercubic group. Having analysed more than half of the available configurations, the result obtained is \xi^2_L = 0.06 \pm 0.02.Comment: Lattice 99 (matrix elements), 3 page

The heavy quark's self energy from moving NRQCD on the lattice

We present a calculation of the heavy quark's self energy in moving NRQCD to one-loop in perturbation theory. Results for the energy shift and external momentum renormalisation are discussed and compared with non-perturbative results. We show that the momentum renormalisation is small, which is the result of a remnant of re-parameterisation invariance on the lattice.Comment: Talk given at Lattice2004(heavy), Fermilab, June 21-26, 200

Hadronic decays from the lattice

I review the lattice QCD approach to determining hadronic decay transitions. Examples considered include rho to pi pi; b_1 to pi omega; hybrid meson decays and scalar meson decays. I discuss what lattices can provide to help understand the composition of hadrons.Comment: 6 pages, presented at QNP06, June 200

Excited B mesons from the lattice

We determine the energies of the excited states of a heavy-light meson $Q\bar{q}$, with a static heavy quark and light quark with mass approximately that of the strange quark from both quenched lattices and with dynamical fermions. We are able to explore the energies of orbital excitations up to L=3, the spin-orbit splitting up to L=2 and the first radial excitation. These $b \bar{s}$ mesons will be very narrow if their mass is less than 5775 MeV -- the $BK$ threshold. We investigate this in detail and present evidence that the scalar meson (L=1) will be very narrow and that as many as 6 $b \bar{s}$ excited states will have energies close to the $BK$ threshold and should also be relatively narrow.Comment: 17 pages, 6 ps figure