The six quark state(uuddss) called H dibaryon($J^P=0^+$,$S=-2$) has been calculated to study its existence and stability. The simulations are performed in quenched QCD on $8^3 \times 24$ and $16^3 \times 48$ anisotropic lattices with Symanzik improved gauge action and Clover fermion action. The gauge coupling is $β=2.0$ and aspect ratio $ξ=a_s/a_t=3.0$. Preliminary results indicate that mass of H dibaryon is 2134(100)Mev on $8^3 \times 24$ lattice and 2167(59)Mev on $16^3 \times 48$ respectively. It seems that the radius of H dibaryon is very large and the finite size effect is very obvious.
We show recent results from the Mainz group using $N_f = 2 + 1$ CLS ensembles generated at the $SU(3)$ symmetric point. Temporal correlation functions using two-baryon interpolating operators are calculated with the distillation method. In addition to the spin-0 operators relevant for studying the $H$ dibaryon, we added spin-1 operators to our basis, thereby extending our results to other flavor sectors. These preliminary results show a finite-volume energy below the $ΛΛ$ threshold. Further calculations are necessary to establish whether the $H$ dibaryon is bound at the physical point.
We present preliminary results from a lattice QCD calculation of the H-dibaryon using two flavors of $\mathcal{O}(a)$ improved Wilson fermions. We employ local six-quark interpolating operators at the source with a combination of local six-quark and two-baryon operators at the sink with the appropriate quantum numbers of the H-dibaryon and its coupling to the two-baryon channels. We find that the two-baryon operators provide an improved overlap onto the ground state in comparison to the local six-quark operators. We also apply Lüscher's finite volume formalism to obtain information on the natu…
Preliminary study of the $H$ dibaryon in $N_{\rm f}=2+1$ lattice QCD
Kent State University(肯特州立大学);University of California, Berkeley(加州大学伯克利分校);Lawrence Berkeley National Laboratory(劳伦斯伯克利国家实验室);Carnegie Mellon University(卡内基梅隆大学);University of North Carolina(北卡罗来纳大学);University of Bern(伯尔尼大学);Johannes Gutenberg University Mainz(美因茨约翰内斯古腾堡大学)
After a brief review of discovery of the H-dibaryon in lattice QCD, effect of the flavor SU(3) symmetry breaking on the H-dibaryon is studied by basing on the baryon-baryon (BB) interactions extracted from QCD on the lattice. The Schrodinger equation for Lambda Lambda - N Xi -Sigma Sigma coupled-channel is solved with the physical baryon masses and the potentials obtained from QCD at the flavor SU(3) limit. A resonant H-dibaryon is found between Lambda Lambda and N Xi thresholds in this treatment.
The current constraints from lattice QCD on the existence of the H-dibaryon are discussed. With only two significant lattice QCD calculations of the H-dibaryon binding energy at approximately the same lattice spacing, the forms of the chiral and continuum extrapolations to the physical point are not determined. In this brief report, we consider the constraints on the H-dibaryon imposed by two simple chiral extrapolations. In both instances, the extrapolation to the physical pion mass allows for a bound H-dibaryon or a near-threshold scattering state. Further lattice QCD calculations are requir…
We study a hypothetical $Δ^0Δ^0$ dibaryon state by means of QCD sum rule method. We construct a scalar interpolating current to extract the mass and decay constant of this state taking into account contributions of various quark, gluon and mixed vacuum condensates. The predictions for the mass and decay constants are $m_D=2326^{+114}_{-126} ~\mathrm{MeV}$ and $f_D=2.94^{+0.30}_{-0.34}\times 10^{-4} ~\mathrm{GeV}^7$, respectively. We also made an estimation about binding energy and size of the $Δ^0Δ^0$ dibaryon. The obtained mass value is below the $Δ^0Δ^0$ threshold and may be a good dibaryon …
Using a new method recently proposed by the HAL QCD collaboration to study hadron interactions in lattice QCD, we investigate a possibility for an existence of the H-dibaryon in the flavor SU(3) symmetric world. A potential for the flavor-singlet baryon-baryon channel is derived from the Nambu-Bethe-Salpeter wave function, and the elusive H-dibaryon is shown to be a bound state, with the binding energy of 20--50 MeV for the pseudo-scalar meson masses in the range that 469--1171 MeV.
We report the first lattice QCD study of the heavy dibaryons in which all six quarks have the bottom (beauty) flavor. Performing a state-of-the-art lattice QCD calculation we find clear evidence for a deeply bound $Ω_{bbb}$-$Ω_{bbb}$ dibaryon in the $^1S_0$ channel, as a pole singularity in the $S$-wave $Ω_{bbb}$-$Ω_{bbb}$ scattering amplitude with a binding energy $-81(_{-16}^{+14})$ MeV. With such a deep binding, Coulomb repulsion serves only as a perturbation on the ground state wave function of the parameterized strong potential and may shift the strong binding only by a few percent. Consi…
The mass of the lowest spin-zero, strangeness-$(-2)$ flavor singlet state in the dibaryon sector has been calculated in quenched QCD on $16^3\times32$ and $24^3\times32$ lattices at $β=5.85$ to study whether the energy of the proposed $H$ dibaryon is near or below the $ΛΛ$ threshold. Preliminary results indicate that finite lattice volume artifacts overestimate the binding, and that on the largest lattice $m_H$ is of the order of $100\MeV$ above the $ΛΛ$ threshold.
Existence of the H-dibaryon in the flavor SU(3) symmetric limit is studied by full QCD simulations on the lattice, in the approach recently developed for the baryon-baryon (BB) interactions. Potential of the flavor-singlet BB channel is derived from the Nambu-Bethe-Salpeter wave function, and a bound H-dibaryon is discovered from it, with the binding energy of 20--50 MeV for the pseudo-scalar meson mass of 469--1171 MeV.
We present evidence for the existence of a bound H-dibaryon, an I=0, J=0, s=-2 state with valence quark structure uuddss, at a pion mass of m_pi ~ 389 MeV. Using the results of Lattice QCD calculations performed on four ensembles of anisotropic clover gauge-field configurations, with spatial extents of L ~ 2.0, 2.5, 3.0 and 3.9 fm at a spatial lattice spacing of b ~ 0.123 fm, we find an H-dibaryon bound by B = 16.6 +- 2.1 +- 4.6 MeV at a pion mass of m_pi ~ 389 MeV.
The flavor-singlet H-dibaryon, which has strangeness -2 and baryon number 2, is studied by the approach recently developed for the baryon-baryon interactions in lattice QCD. The flavor-singlet central potential is derived from the spatial and imaginary-time dependence of the Nambu-Bethe-Salpeter wave function measured in N_f=3 full QCD simulations with the lattice size of L = 2, 3, 4 fm. The potential is found to be insensitive to the volume, and it leads to a bound H-dibaryon with the binding energy of 30 - 40 MeV for the pseudo-scalar meson mass of 673 - 1015 MeV.
We investigate the H-dibaryon, an $I(J^{P})=0(0^{+})$ with $s=-2$, in the chiral and continuum regimes on anisotropic lattices in quenched QCD. Simulations are performed on very coarse lattices with refined techniques to obtain results with high accuracy over a spatial lattice spacing in the range of $a_{s} \sim 0.19 - 0.41$ fm. We present results for the energy difference between the ground state energy of the hexa-quark stranglet and the free two-baryon state from our ensembles. A negative binding energy observed in the chirally extrapolated results leads to the conclusion that the measured …
We present preliminary results for the mass of the 6q flavor-singlet state ($J^P=0^+$, $S=-2$) called H-dibaryon, calculated in quenched QCD on $16^3$x30 and $24^3$x30 lattices with improved gauge and fermion actions (Symanzik improvement, Clover action). For both lattice sizes we applied the fuzzing technique to enhance the overlap with the ground state. We observe a H-mass above the $ΛΛ$ threshold for strong decay. The difference in mass, $m_H - 2m_Λ$, increases with increasing lattice size.
We report the first lattice quantum chromodynamics (QCD) study of deuteron($np$)-like dibaryons with heavy quark flavours. These include particles with following dibaryon structures and valence quark contents: $Σ_cΞ_{cc} (uucucc)$, $Ω_cΩ_{cc} (sscscc)$, $Σ_bΞ_{bb} (uububb)$, $Ω_bΩ_{bb} (ssbsbb)$ and $Ω_{ccb}Ω_{cbb} (ccbcbb)$, and with spin ($J$)-parity ($P$), $J^{P} \equiv 1^{+}$. Using a state-of-the art lattice QCD calculation, after controlling relevant systematic errors, we unambiguously find that the ground state masses of dibaryons $Ω_cΩ_{cc} (sscscc)$, $Ω_bΩ_{bb} (ssbsbb)$ and $Ω_{ccb}Ω…
We present results of the first lattice QCD calculation of three-flavored heavy dibaryons both in the flavor-symmetric and antisymmetric channels. These dibaryons have spin zero, and are constructed using various possible combinations of quark flavors with at least one of them as the charm or the bottom quark, i.e., namely, $H_c(cudcud), H_b(budbud), H_{bcs}(bcsbcs)$, $H_{csl}(cslcsl), H_{bsl}(bslbsl)$ and $H_{bcl}(bclbcl)$; $l\in u,d$. We compute the ground state masses of these dibaryons and the calculations are performed on three $N_f=2+1+1$ HISQ gauge ensembles of the MILC collaboration, w…
Baryon-baryon potentials are obtained from 3-flavor QCD simulations with the lattice volume L ~ 4 fm, the lattice spacing a ~ 0.12 fm, and the pseudo-scalar-meson mass M_ps =469 - 1171 MeV. The NN scattering phase shift and the mass of H-dibaryon in the flavor SU(3) limit are extracted from the resultant potentials by solving the Schrodinger equation. The NN phase shift in the SU(3) limit is shown to have qualitatively similar behavior as the experimental data. A bound H-dibaryon in the SU(3) limit is found to exist in the flavor-singlet J^P=0^+ channel with the binding energy of about 26 MeV …
We investigate properties of the $N$(nucleon)-$Ω$(Omega) interaction in lattice QCD to seek for possible dibaryon states in the strangeness $-3$ channel. We calculate the $NΩ$ potential through the equal-time Nambu-Bethe-Salpeter wave function in 2+1 flavor lattice QCD with the renormalization group improved Iwasaki gauge action and the nonperturbatively $\mathcal{O}(a)$ improved Wilson quark action at the lattice spacing $a\simeq 0.12$ fm on a (1.9 fm)$^{3}\times$ 3.8 fm lattice. The $ud$ and $s$ quark masses in our study correspond to $m_π= 875(1)$ MeV and $m_{K}= 916(1)$ MeV. At these param…
We present our final results for the mass of the six quark flavor singlet state (J^P=0^+, S=-2) called H dibaryon, which would be the lightest possible strangelet in the context of strange quark matter. The calculations are performed in quenched QCD on (8-24)^3 x 30 lattices with the (1,2) Symanzik improved gauge action and the clover fermion action. Furthermore the fuzzing technique for the fermion fields and smearing of the gauge fields is applied in order to enhance the overlap with the ground state. Depending on the lattice size we observe an H mass slightly above or comparable with the ΛΛ…
Recent lattice QCD calculations from the HAL and NPLQCD Collaborations have reported evidence for the existence of a bound state with strangeness -2 and baryon number 2 at quark masses somewhat higher than the physical values. A controlled chiral extrapolation of these lattice results to the physical point suggested that the state, identified with the famed H dibaryon, is most likely slightly unbound (by 13 $\pm$ 14 MeV) with respect to the $Λ--Λ$ threshold. We report the results of an updated analysis which finds the H unbound by 26 $\pm$ 11 MeV. Apart from the insight it would give us into h…
The $ΩΩ$ system in the $^1S_0$ channel (the most strange dibaryon) is studied on the basis of the (2+1)-flavor lattice QCD simulations with a large volume (8.1 fm)$^3$ and nearly physical pion mass $m_π\simeq 146$ MeV at a lattice spacing $a\simeq 0.0846$ fm. We show that lattice QCD data analysis by the HAL QCD method leads to the scattering length $a_0 = 4.6 (6)(^{+1.2}_{-0.5}) {\rm fm}$, the effective range $r_{\rm eff} = 1.27 (3)(^{+0.06}_{-0.03}) {\rm fm}$ and the binding energy $B_{ΩΩ} = 1.6 (6) (^{+0.7}_{-0.6}) {\rm MeV}$. These results indicate that the $ΩΩ$ system has an overall attra…
A pair of triply charmed baryons, $Ω_{ccc}Ω_{ccc}$, is studied as an ideal dibaryon system by (2+1)-flavor lattice QCD with nearly physical light-quark masses and the relativistic heavy quark action with the physical charm quark mass. The spatial baryon-baryon correlation is related to their scattering parameters on the basis of the HAL QCD method. The $Ω_{ccc}Ω_{ccc}$ in the ${^1S_0}$ channel taking into account the Coulomb repulsion with the charge form factor of $Ω_{ccc}$ leads to the scattering length $a^{\rm C}_0\simeq -19~\text{fm}$ and the effective range $r^{\rm C}_{\mathrm{eff}}\simeq…
We present early results from a lattice QCD study seeking a bound $H$-dibaryon using $N_f=2$ flavors of $O(a)$ improved Wilson fermions and a quenched strange quark. We compute a matrix of two-point functions using operators consisting of the two independent local products of six positive-parity-projected quarks with the appropriate quantum numbers, which belong to the singlet and 27-plet irreducible representations of flavor SU(3). To expand this basis, we also independently vary the quark-field smearing, and apply a new scheme to reduce the noise caused by smearing. We then find the ground-s…
Study of the $Ω_{ccc}Ω_{ccc}$ and $Ω_{bbb}Ω_{bbb}$ dibaryons in QCD Sum Rules
School of Physics, Sun Yat-sen University(中山大学物理学院);School of Physical Sciences, University of Chinese Academy of Sciences(中国科学院大学物理科学学院);Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences(中国科学院近代物理研究所南方核科学理论中心)
The $ΔΔ$ dibaryon resonance $d^\ast (2380)$ with $(J^P, I)=(3^+, 0)$ is studied theoretically on the basis of the 3-flavor lattice QCD simulation with heavy pion masses ($m_π=679, 841$ and $1018$ MeV). By using the HAL QCD method, the central $Δ$-$Δ$ potential in the ${}^7S_3$ channel is obtained from the lattice data with the lattice spacing $a\simeq 0.121$ fm and the lattice size $L\simeq 3.87$ fm. The resultant potential shows a strong short-range attraction, so that a quasi-bound state corresponding to $d^\ast (2380)$ is formed with the binding energy $25$-$40$ MeV below the $ΔΔ$ threshold…
We present the first study of baryon-baryon interactions in the continuum limit of lattice QCD, finding unexpectedly large lattice artifacts. Specifically, we determine the binding energy of the $H$ dibaryon at a single quark-mass point. The calculation is performed at six values of the lattice spacing $a$, using O($a$)-improved Wilson fermions at the SU(3)-symmetric point with $m_π=m_K\approx 420$ MeV. Energy levels are extracted by applying a variational method to correlation matrices of bilocal two-baryon interpolating operators computed using the distillation technique. Our analysis employ…
We present a lattice QCD spectroscopy study in the isospin singlet, strangeness $-2$ sectors relevant for the conjectured $H$ dibaryon. We employ both local and bilocal interpolating operators to isolate the ground state in the rest frame and in moving frames. Calculations are performed using two flavors of O($a$)-improved Wilson fermions and a quenched strange quark. Our initial point-source method for constructing correlators does not allow for bilocal operators at the source; nevertheless, results from using these operators at the sink indicate that they provide an improved overlap onto the…
We present the first lattice study of dibaryons with highest bottom number. Utilizing a set of state-of-the-art lattice QCD ensembles and methodologies, we determine the ground state of dibaryon composed of two $Ω_{bbb}$ baryons. We extract the related scattering amplitude in the $^1S_0$ channel and find a sub-threshold pole, which signifies an unambiguous evidence for a deeply bound $Ω_{bbb}-Ω_{bbb}$ dibaryon. The binding energy of such a state as dictated by this pole singularity is found to be -81($^{+14}_{-16}$) MeV. We quantify various systematic uncertainties involved in this determinati…
We explore the possibility of very heavy dibaryons with three charm quarks and three beauty quarks, $bbbccc$, using a constituent model which should drive to the correct solution in the limit of hadrons made of heavy quarks. The six-body problem is treated rigorously, in particular taking into account the orbital, color and spin mixed-symmetry components of the wave function. Unlike a recent claim based on lattice QCD, no bound state is found below the lowest dissociation threshold.
We present first results for two-baryon correlation functions, computed using $N_f=2$ flavours of O($a$) improved Wilson quarks, with the aim of explaining potential dibaryon bound states, specifically the H-dibaryon. In particular, we use a GEVP to isolate the groundstate using two-baryon (hyperon-hyperon) correlation functions $\big(\langle C_{XY}(t)C_{XY}(0) \rangle$, where $XY=ΛΛ, ΣΣ, NΞ, \cdots\big)$, each of which has an overlap with the H-dibaryon. We employ a `blocking' algorithm to handle the large number of contractions, which may easily be extended to N-baryon correlation functions.…
We present a first study on a pair of triply charmed baryons, $Ω_{ccc}Ω_{ccc}$ in the $^1S_0$ channel, on the basis of the HAL QCD method. The measurements are perfomed on the $(2+1)$-flavor lattice QCD configurations with nearly physical light-quark masses and physical charm-quark mass. We show that the system with the Coulomb repulsion taking into account the charge form factor of $Ω_{ccc}$ leads to the scattering length $a^\mathrm{C}_0\simeq-19$ fm and the effective range $r^\mathrm{C}_\mathrm{eff}\simeq0.45$ fm, which indicates $Ω_{ccc}Ω_{ccc}$ is located in the unitary regime.
The nucleon($N$)-Omega($Ω$) system in the S-wave and spin-2 channel ($^5$S$_2$) is studied from the (2+1)-flavor lattice QCD with nearly physical quark masses ($m_π\simeq 146$~MeV and $m_K \simeq 525$~MeV). The time-dependent HAL QCD method is employed to convert the lattice QCD data of the two-baryon correlation function to the baryon-baryon potential and eventually to the scattering observables. The $NΩ$($^5$S$_2$) potential, obtained under the assumption that its couplings to the D-wave octet-baryon pairs are small, is found to be attractive in all distances and to produce a quasi-bound sta…
The strangeness $S=-2$ baryon-baryon interaction is investigated directly from the fundamental theory of the strong interaction, QCD. The HAL QCD method enables us to extract baryon interactions from the Nambu-Bethe-Salpeter wave functions without using any experimental information. We present our latest result on the $S = -2$ baryon interactions and discuss the H-dibaryon state using potentials which are calculated by using the (almost) physical point gauge configurations with large lattice volume of$(8.1{\rm{fm}})^4$ generated on the K-computer.
The simulation of QCD on dynamical (Nf=2) anisotropic lattices is described. A method for nonperturbative renormalisation of the parameters in the anisotropic gauge and quark actions is presented. The precision with which this tuning can be carried out is determined in dynamical simulations on 8^3x48 and 8^3x80 lattices.
We discuss the implementation of QCD on 2+2 anisotropic lattices. Technical details regarding the choice of the action as well as perturbative and non-perturbative improvement are analyzed. The physical applications of the program are presented.
We review our strategy to study hadron interactions from lattice QCD using newly proposed potential method. We first explain our strategy in the case of nuclear potentials and its application to nuclear physics. We then discuss the origin of the repulsive core, by adding strange quarks to the system. We also explore a possibility for H-dibaryon to exist in flavor SU(3) limit of lattice QCD. We conclude the paper with an application of our strategy to investigate the maximum mass of neutron stars.
We present preliminary results for a non perturbative determination of the parameters in the action required to restore Lorentz invariance in long distance correlators, using the static interquark potential. Comparison with analytical results is made and further applications are discussed.
The FASTSUM Collaboration presents its first results for the electric charge susceptibility in QCD using 2+1 dynamical flavours of Wilson quark on anisotropic lattices. Spatial volumes of (2.94 fm)^3 are used at fixed cut-off with temperatures ranging from below T_c to ~2 T_c.
Numerical simulations of full QCD on anisotropic lattices provide a convenient way to study QCD thermodynamics with fixed physics scales and reduced lattice spacing errors. We report results from calculations with two flavors of dynamical staggered fermions, where all bare parameters and the renormalized anisotropy are kept constant and the temperature is changed in small steps by varying only the number of time slices. Including results from zero-temperature scale setting simulations, which determine the Karsch coefficients, allows for the calculation of the equation of state at finite temper…
We describe the first steps in the extension of the Symanzik O($a$) improvement program for Wilson-type quark actions to anisotropic lattices, with a temporal lattice spacing smaller than the spatial one. This provides a fully relativistic and computationally efficient framework for the study of heavy quarks. We illustrate our method with accurate results for the quenched charmonium spectrum.
We present results for mesonic propagators in temporal and spatial direction and for topological properties at T below and above the deconfining transition in quenched QCD. We use anisotropic lattices and Wilson fermions.
We study the glueballs properties at finite temperature using SU(3) lattice QCD at the quenched level with the anisotropic lattice. We use the tree-level Symanzik O(a^2) improved action. We present our preliminary results which shows the slight reduction of the scalar glueball mass near T_c
We investigate the anisotropic lattice with $O(a)$ improved quark action as a candidate of framework in which we can treat both the heavy and light quark region in the same manner and systematically reduce the systematic uncertainties. To examine applicability of anisotropic lattice, we calculate the charmed meson spectrum and decay constants in quenched approximation. We find consistent result with most advanced results on isotropic lattices.
We analyze the meson correlator in the spatial direction at finite temperature. To achieve fine resolution in the spatial direction, we use an anisotropic lattice with the standard Wilson plaquette gauge action and the $O(a)$ improved Wilson quark action. Below and above $T_c$, properties of correlators are investigated by two methods: fits with ansatz for the spectral function, and direct reconstruction of the spectral function using the maximum entropy method.
The mass spectrum of baryons in the spin-3/2 sector is computed in quenched lattice QCD using a tadpole-improved anisotropic action. Both isospin 1/2 and 3/2 (the traditional decuplet) are considered, as well as members that contain strange quarks. States with positive and negative parities are isolated by parity projection, while states with spin-3/2 and spin-1/2 are separated by spin projection. The extent to which spin projection is needed is examined. The issue of optimal interpolating field is also investigated. The results are discussed in relation to previous calculations and experiment…
We calculate the spectrum of excitations in strong-coupling lattice QCD in a background of fixed baryon density, at a substantial fraction of the saturation density. We employ a next-nearest-neighbor fermion formulation that possesses the SU(N_f)xSU(N_f) chiral symmetry of the continuum theory. We find two types of massless excitations: type I Goldstone bosons with linear dispersion relations and type II Goldstone bosons with quadratic dispersion relations. Some of the type I bosons originate as type II bosons of the nearest-neighbor theory. Bosons of either type can develop anisotropic disper…
In lattice QCD, both direct method and HAL QCD method are used to investigate the two-baryon systems. We show that due to the contamination of the scattering excited states, it is challenging to measure the eigenenergy from the temporal correlation in the direct method, while the HAL QCD method can extract the information of the interaction from both scattering states and ground state by using the spatial correlation. We examine the systematic uncertainty of the derivative expansion in the HAL QCD method, which is found to be well under control at the low energies. By using the time-dependent …
We report the first study of the glueball properties at finite temperatures below T_c using SU(3) anisotropic lattice QCD with beta=6.25, the renormalized anisotropy xi \equiv a_s/a_t = 4 and 20^3 \times N_t (N_t=35,36,37,38,40,43,45,50,72) at the quenched level. From the temporal correlation analysis with the smearing method, about 20 % mass reduction is observed for the lowest scalar glueball as m_G(T)=1250 \pm 50MeV for 0.8 T_c < T < T_c in comparison with m_G \simeq 1500 \sim 1700MeV at T \simeq 0.
We present our final results of the charmonium spectrum in quenched QCD on anisotropic lattices. Simulations are made with the plaquette gauge action and a tadpole improved clover quark action employing $ξ= a_s/a_t = 3$. We calculate the spectrum of S- and P-states and their excitation, and study the scaling behavior of mass splittings. Comparison is made with the experiment and previous lattice results. The issue of hyperfine splitting for different choices of the clover coefficients obtained by Klassen is discussed.
The thermal glueball is studied at finite temperature by using SU(3) anisotropic lattice QCD with beta_{lat}=6.25, the renormalized anisotropy xi = a_s/a_t = 4 over the lattice of the size 20^3xN_t with various N_t at the quenched level. While the narrow peak ansatz leads to the significant polemass reduction of about 300 MeV near the critical temperature T_c, Breit-Wigner ansatz which can take into account the possible appearance of the thermal width leads to the significant thermal width broadening of about 300 MeV with a modest reduction of the peak center of about 100 MeV.