We give results for B, Bs, Bc and bottomonium spectroscopy using NRQCD heavy quarks and HISQ valence and sea quarks. Five MILC ensembles of gluon configurations with three values of the lattice spacing and m(light)/m(strange) values down to 0.1 are used that include 2+1+1 flavours of sea quark. Systematic errors in the NRQCD action are improved through the radiative correction of the coefficients of terms at v^4. Improved results for S-wave and P-wave bottomonium states are discussed as well as a prediction for the full D-wave spectrum. Preliminary results for the ground state B meson masses are also presented.
We study S-wave and P-wave bottomonium spectral functions at non-zero temperature in 2+1 flavor QCD using the NRQCD formulation for bottom quarks. We use a novel Bayesian approach to reconstruct the spectral functions and find that $χ_{b1}$ survives up to $T=249 {\rm MeV}$. We also study the effect of different temporal discretizations of the NRQCD formalism on the bottomonium correlation functions
We report our preliminary progress in the calculation of the interquark potential of bottomonium at non-zero temperature using the HAL QCD method. We use NRQCD correlation functions of non-local mesonic S-wave states to obtain the central potential as a function of temperature. These results have been obtained using our anisotropic 2+1 flavour "Generation 2" FASTSUM ensembles.
We report progress in the calculation of the thermal interquark potential of bottomonium using the HAL QCD method applied to bottom quarks in the non-relativistic approximation (i.e. NRQCD). We exploit the fast Fourier transform algorithm, using a momentum space representation, to efficiently calculate NRQCD correlation functions of non-local mesonic S-wave states, and thus obtain the potential for temperatures in both the hadronic and plasma phases. This work was performed on our anisotropic 2+1 flavour ''Generation 2'' FASTSUM ensembles.
The behavior of bottomonium state correlators at non-zero temperature, $140.4 (β= 6.664) \le T \le 221 (β= 7.280)$ (MeV), where the transition temperature is $154(9)$ (MeV), is studied, using lattice NRQCD on $48^3 \times 12$ HotQCD HiSQ action configurations with light dynamical $N_f = 2 + 1$ ($m_{u,s}/m_s = 0.05$) staggered quarks. In order to understand finite temperature effects on quarkonium states, zero temperature behavior of bottomonium correlators is compared based on $32^4$ ($β= 6.664, 6.800$ and $6.950$) and $48^3 \times 64$ ($β= 7.280)$ lattices. We find that temperature effects on…
We present results for the b \bar b spectrum obtained using an O(M_bv^6)-correct non-relativistic lattice QCD action. Propagators are evaluated on SESAM's three sets of dynamical gauge configurations generated with two flavours of Wilson fermions at beta = 5.6. Compared to a quenched simulation at equivalent lattice spacing we find better agreement of our dynamical data with experimental results in the spin-independent sector but observe no unquenching effects in hyperfine-splittings. To pin down the systematic errors we have also compared quenched results in different ``tadpole'' schemes and …
Using Non-Relativistic QCD (NRQCD), we study heavy quark mass dependence of S-wave and P-wave bottomonium correlators for 0.42Tc <= T <= 2.09Tc and study spectral functions of S-wave bottomonium states moving in a thermal bath at these temperatures using Maximum Entropy Method with NRQCD kernel. For the studied momentum range, the energy of moving states shows quadratic momentum-dependence and the width of moving states does not show significant changes as the momentum of bottomonium is increased. Also, we find that in correlator ratios, the temperature effect is larger than the effect caused …
On a cubic lattice the zero-momentum meson states have one of 20 possible Lambda^{PC} combinations where Lambda labels the irreducible representation of the octahedral group. Each continuum bottomonium state with specific J^{PC} quantum numbers is contained within one or more of the lattice Lambda^{PC} states. In this work, bottomonium quark-antiquark operators are constructed for all 20 lattice Lambda^{PC} combinations which allows many continuum high angular momentum states to be accessible as ground states of their associated lattice channels. From a dynamical simulation, realistic results …
We study the fate of P wave bottomonium states in the quark-gluon plasma, using a spectral function analysis of euclidean lattice correlators. The correlators are obtained from lattice QCD simulations with two light quark flavours on highly anisotropic lattices, treating the bottom quark nonrelativistically. We find clear indications of melting immediately after the deconfinement transition.
We study the role of the lattice artifacts associated with the Coulomb binding effects in the analysis of the heavy quarkonium within lattice NRQCD. We find that a "naive" perturbative matching generates spurious linear Coulomb artifacts, which result in a large systematic error in the lattice predictions for the heavy quarkonium spectrum. This effect is responsible, in particular, for the discrepancy between the recent determinations of the bottomonium hyperfine splitting in the radiatively improved lattice NRQCD [1, 2]. We show that the correct matching procedure which provides full control …
We extend our study of bottomonium spectral functions in the quark-gluon plasma to nonzero momentum. We use lattice QCD simulations with two flavours of light quark on highly anisotropic lattices and treat the bottom quark with nonrelativistic QCD (NRQCD). We focus on S wave (Upsilon and eta_b) channels and consider nonrelativistic velocities, v/c < 0.2. A comparison with predictions from effective field theory is made.
We estimate the strong coupling constant from the perturbative expansion of the plaquette. The scale is set by the 2S-1S and 1P-1S splittings in bottomonium which are computed in NRQCD on dynamical gauge configurations with nf=2 degenerate Wilson quarks at intermediate masses. We have increased the statistics of our spectrum calculation in order to reliably extrapolate in the sea-quark mass. We find a value of alpha_MS(m_Z) = 0.1118(26) which is somewhat lower than previous estimates within NRQCD.
We present new results on $Υ$ and $J/Ψ$ spectroscopy using Lattice NRQCD. Charmonium results at quenched $β$ = 5.7 show agreement with experiment within understood systematic errors. We compare bottomonium results at quenched $β$s 6.0 and 5.7 and show that the $1P-1S$ splitting scales with $Λ_V$, provided a correction is applied for the $\cal{O}$$(a^{2})$ errors inherent in the gluon field configurations. There is a clear scale difference between charmonium and bottomonium results in the quenched approximation. We compare quenched results at $β$=6.0 for bottomonium with those obtained on HEMCG…
We present recent results on the in-medium modification of S- and P-wave bottomonium states around the deconfinement transition. Our study uses lattice QCD with $N_f=2+1$ light quark flavors to describe the non-perturbative thermal QCD medium between $140$MeV$<T<249$MeV and deploys lattice regularized non-relativistic QCD (NRQCD) effective field theory to capture the physics of heavy quark bound states immersed therein. The spectral functions of the $^3S_1$ $(Υ)$ and $^3P_1$ $(χ_{b1})$ bottomonium states are extracted from Euclidean time Monte Carlo simulations using a novel Bayesian prescript…
We present an overview of bottomonium spectral functions in the quark-gluon plasma, obtained by the FASTSUM collaboration, using lattice QCD simulations with two light quark flavours on anisotropic lattices. The bottom quark is treated nonrelativistically. While we find that the S wave ground states survive up to the highest temperature we consider, we have strong indications that P wave states melt immediately above Tc.
We present progress results from the FASTSUM collaboration's programme to determine the spectrum of the bottomonium system as a function of temperature using a variety of approaches. In this contribution, the Backus Gilbert method is used to reconstruct spectral functions from NRQCD meson correlator data from FASTSUM's anisotropic ensembles at nonzero temperature. We focus in particular on the resolving power of the method, providing a demonstration of how the underlying resolution functions can be probed by exploiting the Laplacian nature of the NRQCD kernel. We conclude with estimates of the…
We investigate the properties of S-and P-wave bottomonium states in the vicinity of the deconfinement transition temperature. The light degrees of freedom are represented by dynamical lattice QCD configurations of the HotQCD collaboration with $N_f = 2 + 1$ flavors. Bottomonium correlators are obtained from bottom quark propagators, computed in nonrelativistic quantum chromodynamics (NRQCD) under the background of these gauge field configurations. The spectral functions for the $^3S_1$ ($Υ$) and $^3P_1$ ($χ_{b1}$) channel are extracted from the Euclidean time correlators using a novel Bayesian…
Recently, realistic lattice QCD calculations with 2+1 flavors of domain wall fermions and the Iwasaki gauge action have been performed by the RBC and UKQCD collaborations. Here, results for the bottomonium spectrum computed on their gauge configurations of size 24^3x64 with a lattice spacing of approximately 0.11 fm and four different values for the light quark mass are presented. Improved lattice NRQCD is used to treat the b quarks inside the bottomonium. The results for the radial and orbital energy splittings are found to be in good agreement with experimental measurements, indicating that …
We present a calculation of the hyperfine splittings in bottomonium using lattice Nonrelativistic QCD. The calculation includes spin-dependent relativistic corrections through O(v^6), radiative corrections to the leading spin-magnetic coupling and, for the first time, non-perturbative 4-quark interactions which enter at alpha_s^2 v^3. We also include the effect of u,d,s and c quark vacuum polarisation. Our result for the 1S hyperfine splitting is M(Upsilon,1S) - M(eta_b,1S)= 60.0(6.4) MeV. We find the ratio of 2S to 1S hyperfine splittings (M(Upsilon,2S) - M(eta_b,2S))/ (M(Upsilon,1S) - M(eta_…
We apply the background field (BF) method to Non-Relativistic QCD (NRQCD) on the lattice in order to determine the one-loop radiative corrections to the coefficients of the NRQCD action in a manifestly gauge-covariant manner by matching the NRQCD prediction for particular on-shell processes with those of relativistic continuum QCD. We explain how the BF method is implemented in automated perturbation theory and discuss the technique for matching the relativistic and non-relativistic theories. We compute the one-loop radiative corrections to the sigma.B and Darwin terms for the NRQCD action cur…
The HPQCD collaboration has used radiatively-improved NonRelativistic QCD (NRQCD) for $b$ quarks in bottomonium to determine the decay rate of $Υ$ and $Υ^\prime$ mesons to leptons in lattice QCD. Using time-moments of vector bottomonium current-current correlators, we are also able to determine the $b$ quark mass in the $\overline{\mathrm{MS}}$ scheme. We use the same NRQCD $b$ quarks and Highly Improved Staggered Quark (HISQ) light quarks -- with masses down to their physical values -- to give a complete picture of heavy-light meson decay constants including those for vector mesons. We also s…
We present preliminary results using NRQCD to describe heavy quarks on the MILC 2+1 flavour dynamical extra coarse ensemble. We calculate the spectra of low lying states in bottomonium to complement earlier results on the finer MILC ensembles. We then exploit the coarseness of the lattices to calculate charm propagators using NRQCD. These are used to examine the charmonium spectrum and to calclate the mass of the $B_c$ using NRQCD. Finally we look breifly at the $B_d$ and $B_s$ systems using the imporoved staggered formalism to describe the light valence quarks.
We have developed two methods for handling $b$ quarks in lattice QCD. One uses NRQCD (now improved to include radiative corrections) and the other uses Highly Improved Staggered Quarks (HISQ), extrapolating to the $b$ quark from lighter masses and using multiple lattice spacings to control discretisation errors. Comparison of results for the two different methods gives confidence in estimates of lattice QCD systematic errors, since they are very different in these two cases. Here we show results for heavyonium hyperfine splittings and vector current-current correlator moments using HISQ quarks…
We present updated results for the radiative improvement of the σ.B term and the spin-dependent four-fermion terms in the lattice NRQCD action, and first results for the radiative corrections to the NRQCD Darwin term and spin-independent four-fermion terms. The spin-dependent terms have significant impact on getting the correct hyperfine splitting for both bottomonium and heavy-light mesons, while the spin-independent terms suffer from a conspiracy between lattice artifacts and severe IR divergences that complicates their evaluation.
We present the latest results from the use of the Backus-Gilbert method for reconstructing the spectra of NRQCD bottomonium mesons using anisotropic FASTSUM ensembles at non-zero temperature. We focus in particular on results from the $η_b$, $Υ$, $χ_{b1}$ and $h_b$ generated from Tikhonov-regularized Backus-Gilbert coefficient sets. We extend previous work on the Laplace shifting theorem as a means of resolution improvement and present new results from its use. We conclude with a discussion of the limitations of the improvement routine and elucidate a connection with Parisi-Lepage statistical …
We present the first application of the background field method to Non-Relativistic QCD (NRQCD) on the lattice in order to determine the one-loop radiative corrections to the coefficients of the NRQCD action in a manifestly gauge-covariant manner. The coefficient of the $σ\cdot B$ term in the NRQCD action is computed at the one-loop level; the resulting shift of the hyperfine splitting of bottomonium is found to bring the lattice predictions in line with experiment.
Dynamical 2+1 flavor lattice QCD is used to calculate the masses of bottom hadrons, including B mesons, singly and doubly bottom baryons, and for the first time also the triply-bottom baryon Omega_bbb. The domain wall action is used for the up-, down-, and strange quarks (both valence and sea), while the bottom quark is implemented with non-relativistic QCD. A calculation of the bottomonium spectrum is also presented.
To study the in-medium modification of quarkonium properties, charmonium correlators at $140.4 (β=6.664) \le T \le 221 (β= 7.280)$ (MeV) are calculated using the NRQCD formalism on $48^3 \times 12$ gauge configurations with dynamical $N_f = 2 + 1$ flavors of Highly Improved Staggered Quarks (HISQ). To determine the "zero energy shift" for these lattices, we perform a fine zero temperature scan ($β=6.664, 6.740, 6.800, 6.880, 6.950, 7.030, 7.150$ and $7.280$). We find that the temperature dependence of charmonium correlators is stronger than the temperature dependence of bottomonium correlators…
We formulate Non-Relativistic Quantum Chromodynamics (NRQCD) on a lattice which is boosted relative to the usual discretization frame. Moving NRQCD (mNRQCD) allows us to treat the momentum for the heavy quark arising from the frame choice exactly. We derive mNRQCD through O(1/m^2,v^4), as accurate as the NRQCD action in present use, both in the continuum and on the lattice with O(a^4) improvements. We have carried out extensive tests of the formalism through calculations of two-point correlators for both heavy-heavy (bottomonium) and heavy-light (B_s) mesons in 2+1 flavor lattice QCD and obtai…
We compute spin-dependent decay matrix elements for S-wave charmonium and bottomonium in lattice nonrelativistic quantum chromodynamics (NRQCD). Particular emphasis is placed upon the color-octet matrix elements, since the corresponding production matrix elements are expected to appear in the dominant contributions to the production cross sections at large transverse momenta. We use three slightly different versions of the heavy-quark lattice Green's functions in order to minimize the contributions that scale as powers of the ultraviolet cutoff. The lattice matrix elements that we calculate ob…
Using lowest-order lattice NRQCD to create heavy meson propagators and applying the spin-dependent interaction, $c_B^{} \frac{-g}{2m_q}\vecσ\cdot\vec{B}$, at varying intermediate time slices, we compute the off-diagonal matrix element of the Hamiltonian for the quarkonium-hybrid two-state system. Thus far, we have results for one set of quenched lattices with an interpolation in quark mass to match the bottomonium spectrum. After diagonalization of the two-state Hamiltonian, we find the ground state of the $Υ$ to show a $0.0035(1)c_B^2$ (with $c_B^2 \sim 1.5-3.1$) probability admixture of hybr…
The bottomonium spectrum is computed in dynamical 2+1 flavor lattice QCD, using NRQCD for the b quarks. The main calculations in this work are based on gauge field ensembles generated by the RBC and UKQCD collaborations with the Iwasaki action for the gluons and a domain-wall action for the sea quarks. Lattice spacing values of approximately 0.08 fm and 0.11 fm are used, and simultaneous chiral extrapolations to the physical pion mass are performed. As a test for gluon discretization errors, the calculations are repeated on two ensembles generated by the MILC collaboration with the Luscher-Wei…
Lattice NRQCD with leading finite lattice spacing errors removed is used to calculate decay constants of mesons made up of heavy quarks. Quenched simulations are done with a tadpole improved gauge action containing plaquette and six-link rectangular terms. The tadpole factor is estimated using the Landau link. For each of the three values of the coupling constant considered, quarkonia are calculated for five masses spanning the range from charmonium through bottomonium, and one set of quark masses is tuned to the B(c). "Perturbative" and nonperturbative meson masses are compared. One-loop pert…
We study bottomonium spectral functions in the quark-gluon plasma in the Upsilon and eta_b channels, using lattice QCD simulations with two flavours of light quark on highly anisotropic lattices. The bottom quark is treated with nonrelativistic QCD (NRQCD). In the temperature range we consider, 0.42 < T/T_c < 2.09, we find that the ground states survive, whereas the excited states are suppressed as the temperature is increased. The position and width of the ground states are compared to analytical effective field theory (EFT) predictions. Systematic uncertainties of the maximum entropy method …
Using lowest-order lattice NRQCD to create heavy meson propagators and applying the spin-dependent interaction, $c_B^{} \frac{-g}{2m_q}\vecσ\cdot\vec{B}$, at varying intermediate time slices, we compute the off-diagonal matrix element of the Hamiltonian for the quarkonium-hybrid two-state system. Diagonalizing this two-state Hamiltonian, the admixture of hybrid ($|Q\bar{Q}g>$) in the ground state is found. We present results from a set of quenched lattices with an interpolation in quark mass to match the bottomonium spectrum.
We present a quenched calculation of lowest bottomonium hybrid states on an anisotropic lattice with Landau mean-link tadpole improvement, using the improved NRQCD Hamiltonian. We investigate the quark-spin s=0,1 sectors, which contain both the non-exotic 1-- and the exotic 1-+, and demonstrate their degeneracy in the case of the lowest order Hamiltonian. Both states are found at around 1.6 GeV above the Upsilon ground state. We examine the spin-splitting for several hybrid states that is due to the magnetic moment term in the NRQCD Hamiltonian, all other terms having negligible effect. The sp…
I give an overview of phenomenological heavy quark results obtained in NRQCD on the lattice. In particular I discuss the bottomonium and the b-light hadron spectrum. I also review recent results on the decay constants f_B and f_B_s.
We calculate the NRQCD matrix elements for the decays of the lowest-lying S- and P-wave states of charmonium and bottomonium in quenched lattice QCD. We also compute the one-loop relations between the lattice and continuum matrix elements.
We give a progress report on studies of B_s and B_d mixing with valence NRQCD b quarks and asqtad light quarks on the MILC configurations including the effect of 2+1 flavours of sea quarks. We explore methods for reducing statistical and systematic errors in the ratio ξ= f_{B_s}\sqrt{B_{B_s}}/f_{B_d}\sqrt{B_{B_d}}.
Along the years, the Cornell Model has been extraordinarily successful in describing hadronic phenomenology, in particular in physical situations for which an effective theory of the strong interactions such as NRQCD cannot be applied. As a consequence of its achievements, a relevant question is whether its model parameters can somehow be related to fundamental constants of QCD. We shall give a first answer in this article by comparing the predictions of both approaches. Building on results from a previous study on heavy meson spectroscopy, we calibrate the Cornell model employing NRQCD predic…
Using NRQCD b quarks and HISQ light, strange and charm quarks we have calculated B meson masses and B^*-B splittings. We quote results for a range of lattice spacings and sea quark masses, enabling controlled extrapolation to the physical point. Since the $b$ quark masses and lattice spacing are fixed from the Υand other meson masses, this allows accurate, parameter-free tests of B, B_s, and B_c masses against experiment. We can also predict the mass of the B^*_c meson.
We present the first lattice QCD calculation of the decay constants f_B and f_{B_s} with physical light quark masses. We use configurations generated by the MILC collaboration including the effect of u, d, s and c HISQ sea quarks at three lattice spacings and with three u/d quark mass values going down to the physical value. We use improved NRQCD for the valence b quarks. Our results are f_B = 0.186(4) GeV, f_{B_s} = 0.224(5) GeV, f_{B_s}/f_B = 1.205(7) and M_{B_s}-M_B=85(2) MeV, superseding earlier results with NRQCD b quarks. We discuss the implications of our results for the Standard Model …
We present the final results of our high statistics study on the properties of bottomonium and charmonium at finite temperature. We focus on the temperature range around the crossover transition $150\leq T\leq 410$MeV, relevant for current heavy ion collision experiments. The QCD medium degrees of freedom which consist of dynamical u,d, and s quarks and gluons are captured by realistic state-of-the art ($m_π\approx 161$MeV) lattice QCD simulations of the HotQCD collaboration. For the heavy quarks we deploy the non-relativistic effective field theory of QCD, NRQCD. The in-medium properties of q…
We present the status of our ongoing calculation of the zero-recoil form factor for the semileptonic decay $\bar{B}^0\rightarrow D^{*+}l^-\barν$ using lattice QCD with 2+1+1 flavours of highly improved staggered quarks in the sea (the MILC HISQ configurations) and using non-relativistic QCD for the bottom quark. We combine our result for $ F(1)$ with the latest HFAG average of $η_{EW} F(1)|V_{cb}|$ to get a preliminary value for $|V_{cb}|$.
In order to understand the experimental data on heavy quarkonium production in heavy ion collisions at RHIC and LHC it is necessary (though not sufficient) to pinpoint the properties of heavy $Q\bar{Q}$ bound states in the deconfined quark-gluon plasma, including their dissolution. Here we present recent results on the temperature dependence of bottomonium and charmonium correlators, as well as their spectral functions in a lattice QCD based effective field theory called NRQCD, surveying temperatures close to the crossover transition $140 {\rm MeV} < T< 249 {\rm MeV}$. The spectra are reconstr…
We present comprehensive results for the spectrum and decay constants of hadrons containing a single b quark. The heavy quark is simulated using an $O(1/M)$ NRQCD action and the light quark using the $O(a)$ tadpole-improved clover action on gauge configurations containing two degenerate flavours of sea quarks at $β^{n_f=2}=5.6$ provided by the HEMCGC collaboration. We present detailed results for the lower lying $S$ and $P$ wave $B$ meson states and the $Λ_b$ baryon. We find broad agreement with experiment. In addition, we present results for the pseudoscalar and, for the first time, the vecto…
We use the non-relativistic expansion of QCD (NRQCD) on the lattice to study the lowest hybrid configuration contribution to the ground state of heavy S-wave mesons. Using lowest-order lattice NRQCD to create the heavy-quark propagators, we form a basis of ``unperturbed'' S-wave and hybrid states. We then apply the lowest-order coupling of the quark spin and chromomagnetic field at an intermediate time slice to create ``mixed'' correlators between the S-wave and hybrid states. From the resulting amplitudes, we extract the off-diagonal element of our two-state Hamiltonian. Diagonalizing this Ha…
We present a determination of the b-quark mass accurate through O(α_s^2) in perturbation theory and including partial contributions at O(α_s^3). Nonperturbative input comes from the calculation of the Upsilon and B_s energies in lattice QCD including the effect of u, d and s sea quarks. We use an improved NRQCD action for the b-quark. This is combined with the heavy quark energy shift in NRQCD determined using a mixed approach of high-beta simulation and automated lattice perturbation theory. Comparison with experiment enables the quark mass to be extracted: in the MS bar scheme we find m_b(m_…
We derive the imaginary part of the potential NRQCD Hamiltonian up to order 1/m^4, when the typical momentum transfer between the heavy quarks is of the order of Lambda_{QCD} or greater, and the binding energy E much smaller than Lambda_{QCD}. We use this result to calculate the inclusive decay widths into light hadrons, photons and lepton pairs, up to O(mv^3 x (Lambda_{QCD}^2/m^2,E/m)) and O(mv^5) times a short-distance coefficient, for S- and P-wave heavy quarkonium states, respectively. We achieve a large reduction in the number of unknown non-perturbative parameters and, therefore, we obta…
Heavy-light decays such as $B \to π\ell ν$, $B \to K^{*} γ$ and $B \to K^{(*)} \ell \ell$ can be used to constrain the parameters of the Standard Model and in indirect searches for new physics. While the precision of experimental results has improved over the last years this has still to be matched by equally precise theoretical predictions. The calculation of heavy-light form factors is currently carried out in lattice QCD. Due to its small Compton wavelength we discretize the heavy quark in an effective non-relativistic theory. By formulating the theory in a moving frame of reference discret…
We present results on the bottomonium spectrum at temperatures above and below the deconfinement crossover temperature, $T_c$, from dynamical lattice QCD simulations. The heavy quark is treated with a non-relativistic effective field theory on the lattice and serves as a probe of the hot medium. Ensembles with a finer spatial lattice spacing and a greater range of temperatures below $T_c$ than those previously employed by this collaboration are used. In addition, there are $N_f=2+1$ flavours of Wilson clover quark in the sea with $M_π\approx400$ MeV and we perform a more careful tuning of the …
The sequential melting of the bottomonium states is one of the important signals for the existence of a quark gluon plasma. The study of bottomonia spectral functions on the lattice is a difficult task for many reasons. Calculations based on NRQCD, that are commonly used for such purpose, are not applicable at high temperatures. In this work we propose a new method to study this problem by calculating the spatial screening masses of bottomonium states. We calculate the spatial meson correlators and extract the screening masses for mesons in different quantum channels using highly improved stag…
We calculate the full spectrum of D-wave states in the Upsilon system in lattice QCD for the first time, using an improved version of NonRelativistic QCD on coarse and fine "second generation" gluon field configurations from the MILC collaboration that include the effect of up, down, strange and charm quarks in the sea. Taking the 2S-1S splitting to set the lattice spacing, we determine the ^3D_2 - 1S splitting to 2.3%, and find agreement with experiment. Our prediction of the fine structure relative to the ^3D_2 gives the ^3D_3 at 10.181(5) GeV and the ^3D_1 at 10.147(6) GeV. We also discuss …
We present a lattice investigation of the heavy-light meson decay constants using Wilson light quarks and NRQCD heavy quarks, partially including the effects of dynamical sea quarks. We calculate the pseudoscalar and vector decay constants over a wide range in heavy quark mass and are able to perform a detailed analysis of heavy quark symmetry. We find consistency between the extrapolation of the NRQCD results and the static case, as expected. We find the slope of the decay constants with $1/M$ is significantly larger than naive expectations and the results of previous lattice calculations. Fo…
