Brian Colquhoun
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View article: Constraints on axionlike particles using lattice QCD calculations of the rate for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>J</mml:mi><mml:mo>/</mml:mo><mml:mi>ψ</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:mi>γ</mml:mi><mml:mi>a</mml:mi></mml:math>
Constraints on axionlike particles using lattice QCD calculations of the rate for Open
A key search mode for axionlike particles (ALPs) that couple to charm quarks is J/ψ→γa. Here we calculate the form factor that allows the rate of this process to be determined using lattice QCD for the first time. Our calculations use the …
View article: Constraints on axion-like particles using lattice QCD calculations of the rate for $J/ψ\to γa$
Constraints on axion-like particles using lattice QCD calculations of the rate for $J/ψ\to γa$ Open
A key search mode for axion-like particles (ALPs) that couple to charm quarks is $J/ψ\to γa$. Here we calculate the form factor that allows the rate of this process to be determined using lattice QCD for the first time. Our calculations us…
View article: Improved analysis of strong-interaction-stable doubly bottom tetraquarks on the lattice
Improved analysis of strong-interaction-stable doubly bottom tetraquarks on the lattice Open
We update earlier lattice results for the binding energies of the flavor antitriplet of strong-interaction-stable doubly bottom, JP=1+ tetraquarks, employing an extended sink construction which produces significantly improved ground-state …
View article: Precise prediction of the decay rate for $η_b\to γγ$ from lattice QCD
Precise prediction of the decay rate for $η_b\to γγ$ from lattice QCD Open
We calculate the decay rate for $η_b \to γγ$ in lattice QCD for the first time, providing a precise prediction for the Belle II experiment. Our calculation includes $u$, $d$, $s$ and $c$ quarks in the sea, using gluon field configurations …
View article: Improved analysis of strong-interaction-stable doubly-bottom tetraquarks on the lattice
Improved analysis of strong-interaction-stable doubly-bottom tetraquarks on the lattice Open
We update earlier lattice results for the binding energies of the flavor antitriplet of strong-interaction-stable doubly bottom, $J^P=1^+$ tetraquarks, employing an extended sink construction which produces significantly improved ground-st…
View article: $B \to D^*\ellν_\ell$ semileptonic form factors from lattice QCD with Möbius domain-wall quarks
$B \to D^*\ellν_\ell$ semileptonic form factors from lattice QCD with Möbius domain-wall quarks Open
We calculate the form factors for the $B \to D^*\ellν_\ell$ decay in 2+1 flavor lattice QCD. For all quark flavors, we employ the Möbius domain-wall action, which preserves chiral symmetry to a good precision. Our gauge ensembles are gener…
View article: Precise determination of decay rates for $η_c \to γγ$, $J/ψ\to γη_c$ and $J/ψ\to η_c e^+e^-$ from lattice QCD
Precise determination of decay rates for $η_c \to γγ$, $J/ψ\to γη_c$ and $J/ψ\to η_c e^+e^-$ from lattice QCD Open
We calculate the decay rates for $η_c \to γγ$, $J/ψ\to γη_c$ and $J/ψ\to η_c e^+e^-$ in lattice QCD with $u$, $d$, $s$ and $c$ quarks in the sea for the first time. We improve significantly on previous theory calculations to achieve accura…
View article: Precise determination of decay rates for $\eta_c \to \gamma \gamma$ and $J/\psi \to \gamma\eta_c$
Precise determination of decay rates for $\eta_c \to \gamma \gamma$ and $J/\psi \to \gamma\eta_c$ Open
We calculate the decay rates for $\\eta_c\\to\\gamma\\gamma$ and $J/\\psi\\to\\gamma \\eta_c$ in lattice QCD with the effect of $u$, $d$, $s$ and $c$ quarks in the sea for the first time. Our calculations are carried out on gluon field con…
View article: Ruling out some predictions of deeply-bound light-heavy tetraquarks using lattice QCD
Ruling out some predictions of deeply-bound light-heavy tetraquarks using lattice QCD Open
We discuss our lattice QCD calculations of a number of tetraquark channels with at least one heavy quark where some phenomenological models, already fully constrained by fits to the ordinary meson and baryon spectrum, predict deep binding.…
View article: $B \to D^{(*)}\ell\nu$ semileptonic decays in lattice QCD with domain-wall heavy quarks
$B \to D^{(*)}\ell\nu$ semileptonic decays in lattice QCD with domain-wall heavy quarks Open
We calculate the $B \\to D^{(*)} \\ell \\nu$ form factors in 2+1 flavor\nrelativistic lattice QCD by employing the M\\"obius domain-wall action for all\nquark flavors. Our simulations are carried out at lattice cut-offs $a^{-1} \\sim\n2.5$…
View article: Investigating exotic heavy-light tetraquarks with 2+1 flavour lattice QCD
Investigating exotic heavy-light tetraquarks with 2+1 flavour lattice QCD Open
There are a number of tetraquark channels for which some phenomenological models -- already constrained by the ordinary meson and baryon spectrum -- predict deep binding. We present results from our lattice calculations of doubly-charmed a…
View article: Form factors of $B\toπ\ellν$ and a determination of $|V_{ub}|$ with Möbius domain-wall-fermions
Form factors of $B\toπ\ellν$ and a determination of $|V_{ub}|$ with Möbius domain-wall-fermions Open
Using a fully relativistic lattice fermion action, we compute the form factors of the semileptonic decay $B\toπ\ellν$, which is required for the determination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|$. We employ the Möbius…
View article: Semiclassical regime for dark matter self-interactions
Semiclassical regime for dark matter self-interactions Open
Many particle physics models for dark matter self-interactions—motivated to address long-standing challenges to the collisionless cold dark matter paradigm—fall within the semiclassical regime, with interaction potentials that are long ran…
View article: Lattice investigation of exotic tetraquark channels
Lattice investigation of exotic tetraquark channels Open
We perform an $n_f=2+1$ lattice study of a number of channels where past claims exist in the literature for the existence of strong-interaction-stable light-heavy tetraquarks. We find no evidence for any such deeply-bound states, beyond th…
View article: $B \to D^{(*)}\ell\nu$ form factors from lattice QCD with relativistic heavy quarks
$B \to D^{(*)}\ell\nu$ form factors from lattice QCD with relativistic heavy quarks Open
We report on our calculation of the $B \to D^{(*)}\ell\nu$ form factors in 2+1 flavor lattice QCD. The Moebius domain-wall action is employed for light, strange, charm and bottom quarks. At lattice cutoffs $a^{-1} \sim 2.4$, 3.6 and 4.5 Ge…
View article: $B \to \pi\ell\nu$ form factors and $|V_{ub}|$ with Möbius domain wall fermions
$B \to \pi\ell\nu$ form factors and $|V_{ub}|$ with Möbius domain wall fermions Open
We report on a calculation of form factors for the semileptonic decay of $B$ meson to pion on $2+1$-flavour lattices with lattice spacings from 0.080 fm down to 0.044 fm. Using the M\"obius domain wall fermion action for both sea and valen…
View article: $B\!\to\!D^{(*)}\ellν$ form factors from lattice QCD with relativistic heavy quarks
$B\!\to\!D^{(*)}\ellν$ form factors from lattice QCD with relativistic heavy quarks Open
We report on our calculation of the B \to D^(*) \ell νform factors in 2+1 flavor lattice QCD. The Möbius domain-wall action is employed for light, strange, charm and bottom quarks. At lattice cutoffs 1/a \sim 2.4, 3.6 and 4.5 GeV, we simul…
View article: $B \to π\ellν$ form factors and $|V_{ub}|$ with Möbius domain wall fermions
$B \to π\ellν$ form factors and $|V_{ub}|$ with Möbius domain wall fermions Open
We report on a calculation of form factors for the semileptonic decay of $B$ meson to pion on $2+1$-flavour lattices with lattice spacings from 0.080 fm down to 0.044 fm. Using the Möbius domain wall fermion action for both sea and valence…
View article: $B \to \pi\ell\nu$ form factors and $|V_{ub}|$ with M\"obius domain wall fermions
$B \to \pi\ell\nu$ form factors and $|V_{ub}|$ with M\"obius domain wall fermions Open
We report on a calculation of form factors for the semileptonic decay of $B$ meson to pion on $2+1$-flavour lattices with lattice spacings from 0.080 fm down to 0.044 fm. Using the M\"obius domain wall fermion action for both sea and valen…
View article: Heavy quark scaling of $B \to \pi \ell \nu$ form factors with Möbius domain wall fermions
Heavy quark scaling of $B \to \pi \ell \nu$ form factors with Möbius domain wall fermions Open
We report on the progress of our calculation of form factors for the exclusive semileptonic decay of $B$ mesons to pions on $2+1$ flavour lattices with spacings from $0.080~\mathrm{fm}$ down to $0.044~\mathrm{fm}$. Using the Mobius domain …
View article: $B \to D^{(*)}\ell\nu$ form factors from $N_f$=2+1 QCD with Möbius domain-wall quarks
$B \to D^{(*)}\ell\nu$ form factors from $N_f$=2+1 QCD with Möbius domain-wall quarks Open
We report on our study of the $B \to D^{(*)}\ell\nu$ semileptonic decays at zero and nonzero recoils in 2+1 flavor QCD. The M\"obius domain-wall action is employed for light, charm and bottom quarks at lattice cutoffs $a^{-1}$ = 2.5 and 3.…
View article: $B_c$ spectroscopy using highly improved staggered quarks
$B_c$ spectroscopy using highly improved staggered quarks Open
We report on a calculation of $B_c$ ground state and radial excitation energies, obtained from heavy-charm highly improved staggered quark (HISQ) correlators computed on MILC gauge ensembles, with lattice spacings down to $a=0.044$ fm. Usi…
View article: Inclusive decay structure function for $B\to X_c\ell\nu$: a comparison of a lattice calculation with the heavy quark expansion
Inclusive decay structure function for $B\to X_c\ell\nu$: a comparison of a lattice calculation with the heavy quark expansion Open
A lattice calculation of inclusive decay structure functions for $B\to X_c\ell\nu$ is compared with the corresponding estimates based on the heavy quark expansion. Both methods are applicable in the region away from the resonances/cuts due…
View article: $B \to D^{(*)}\ellν$ form factors from $N_f\!=\!2+1$ QCD with Möbius domain-wall quarks
$B \to D^{(*)}\ellν$ form factors from $N_f\!=\!2+1$ QCD with Möbius domain-wall quarks Open
We report on our study of the B \to D^(*) \ell νsemileptonic decays at zero and nonzero recoils in 2+1 flavor QCD. The Möbius domain-wall action is employed for light, charm and bottom quarks at lattice cutoffs 1/a = 2.5 and 3.6 GeV. We ta…
View article: Heavy quark scaling of $B\toπ\ellν$ form factors with Möbius domain wall fermions
Heavy quark scaling of $B\toπ\ellν$ form factors with Möbius domain wall fermions Open
We report on the progress of our calculation of form factors for the exclusive semileptonic decay of $B$ mesons to pions on $2+1$ flavour lattices with spacings from $0.080~\mathrm{fm}$ down to $0.044~\mathrm{fm}$. Using the Möbius domain …
View article: <i>B</i> → <i>πlv</i> with Möbius Domain Wall Fermions
<i>B</i> → <i>πlv</i> with Möbius Domain Wall Fermions Open
We report on the status of our calculation of the exclusive semileptonic decay, B → πlv ; a key process in the determination of the CKM matrix element | V ub |. The Möbius domain wall action is used for both light and heavy quarks on gauge…
View article: Inclusive <i>B</i> decay calculations with analytic continuation
Inclusive <i>B</i> decay calculations with analytic continuation Open
First-principle lattice calculation of inclusive B meson semileptonic decays is possible for a certain class of moments that is connected to the structure function at unphysical kinematics by analytic continuation. We present an explorator…
View article: $B \rightarrow π\ell ν$ with Möbius Domain Wall Fermions
$B \rightarrow π\ell ν$ with Möbius Domain Wall Fermions Open
We report on the status of our calculation of the exclusive semileptonic decay, $B\rightarrow π\ell ν$; a key process in the determination of the CKM matrix element $|V_{ub}|$. The Möbius domain wall action is used for both light and heavy…