Fri·Dec 2, 2022Friday·December 2, 2022

1. 01*

   Lattice study on a tetraquark state $T_{bb}$ in the HAL QCD method

   Sinya Aoki🇯🇵 · Takafumi Aoki🇯🇵

   We investigate a doubly-bottomed tetraquark state $T_{bb}$ $(bb\bar{u}\bar{d})$ with quantum number $I(J^P)=0(1^{+})$ in $(2+1)$-flavor lattice QCD. Using the Non-Relativistic QCD (NRQCD) quark action for $b$ quarks, we have extracted the coupled channel potential between $\bar{B}{\bar{B}}^{\ast }$ and ${\bar{B}}^{\ast }{\bar{B}}^{\ast }$ in the HAL QCD method at $a\approx 0.09$ {fm} on $32^3\times 64$ lattices. The potential predicts an existence of a bound $T_{bb}$ below the $\bar{B}{\bar{B}}^{\ast }$ threshold. At the physical pion mass $m_{\pi }\approx 140$ {MeV} extrapolated from $m_{\pi }\approx 410,570,700$ {MeV}, a binding energy with its statistical error is given by $E_{\mathrm{binding}}^{(\mathrm{coupled})}=83(10)$ MeV from a coupled channel analysis where effects due to virtual ${\bar{B}}^{\ast }{\bar{B}}^{\ast }$ states are included through the coupled channel potential, while we obtain $E_{\mathrm{binding}}^{(\mathrm{single})}=155(17)$ MeV only from a potential for a single $\bar{B}{\bar{B}}^{\ast }$ channel. This difference indicates that the effect from virtual ${\bar{B}}^{\ast }{\bar{B}}^{\ast }$ states is sizable to the binding energy of $T_{bb}$. Adding $\pm 20$ MeV as empirical systematic error caused by the NRQCD approximation for $b$ quarks, our estimate of the $T_{bb}$ binding energy becomes $83(10)(20)$ MeV.

   hep-latnucl-thPoS(2023)·7 citations
2. 02*

   Calculation of the pion charge radius from an improved model-independent method

   Kohei Sato🇯🇵 · Hiromasa Watanabe🇯🇵 · Takeshi Yamazaki🇯🇵

   We propose a new improved model-independent method for calculating the pion charge radius. In a recently-proposed model-independent method for the pion charge radius, we find it difficult to compute the pion charge radius for small pole mass $M_{\mathrm{pole}}^2$ and volume due to systematic errors coming from finite volume effect and higher-order contamination of the Taylor expansion of the form factor. We circumvent this difficulty by introducing a new appropriate function and propose a modified method that can calculate the pion charge radius with less systematic errors in the small $M_{\mathrm{pole}}^2$ and volume cases. As preliminary results, we check that our improved model-independent method works well on a mockup data and also an actual lattice QCD data at the pion mass of 0.51 GeV.

   hep-latPoS(2023)·4 citations
3. 03*

   Momentum transfer dependence of kaon semileptonic form factor on (10 fm)${}^4$ at the physical point

   Takeshi Yamazaki🇯🇵 · Ken-ichi Ishikawa🇯🇵 · Naruhito Ishizuka🇯🇵 · Yoshinobu Kuramashi🇯🇵 · Yusuke Namekawa🇯🇵 · Yusuke Taniguchi🇯🇵 · Naoya Ukita🇯🇵 · Tomoteru Yoshié for PACS Collaboration🇯🇵

   We calculate the kaon semileptonic form factors using the two sets of the PACS10 configuration, whose physical volumes are more than (10 fm)${}^4$ at the physical point. The lattice spacings are 0.063 and 0.085 fm. The configurations were generated using the Iwasaki gauge action and $N_f=2+1$ stout-smeared nonperturbatively $O(a)$-improved Wilson quark action. From the momentum transfer dependence of the form factors, we evaluate the slope and curvature for the form factors at the zero momentum transfer. Furthermore, we calculate the phase space factor, which is used to obtain $|V_{us}|$ through the kaon semileptonic decay. These results are compared with previous lattice results and experimental values.

   hep-latPoS(2023)·0 citations
4. 04*

   Understanding the $0^{++}$ and $2^{++}$ charmonium(-like) states near 3.9 GeV

   Teng Ji🇨🇳 · Xiang-Kun Dong🇨🇳 · Miguel Albaladejo🇪🇸 · Meng-Lin Du🇪🇸 · Feng-Kun Guo🇨🇳 · Juan Nieves🇪🇸 · Bing-Song Zou🇨🇳

   We propose that the $X(3915)$ observed in the $J/\psi \omega$ channel is the same state as the ${\chi }_{c2}(3930)$, and the $X(3960)$, observed in the $D_s^{+}{D}_s^{-}$ channel, is an $S$-wave $D_s^{+}{D}_s^{-}$ hadronic molecule. In addition, the $J^{PC}=0^{++}$ {component in the $B^{+}\to D^{+}{D}^{-}{K}^{+}$} assigned to the $X(3915)$ in the current {\it Review of Particle Physics} has the same origin as the $X(3960)$, which has a mass around 3.94~GeV. To check the proposal, the available data in the $D\bar{D}$ and $D_s^{+}{D}_s^{-}$ channels from both $B$ decays and $\gamma \gamma$ fusion reaction are analyzed considering both the $D\bar{D}$-$D_s{\bar{D}}_s$-$D^{\ast }{\bar{D}}^{\ast }$-$D_s^{\ast }{\bar{D}}_s^{\ast }$ coupled channels with $0^{++}$ and a $2^{++}$ state introduced additionally. It is found that all the data in different processes can be simultaneously well reproduced, and the coupled-channel dynamics produce four hidden-charm scalar molecular states with masses around 3.73, 3.94, 3.99 and 4.23~GeV, respectively. The results may deepen our understanding of the spectrum of charmonia as well as of the interactions between charmed hadrons.

   ↳ hep-phhep-exhep-latSci.Bull.(2023)·34 citations
5. 05*

   Variational Neural-Network Ansatz for Continuum Quantum Field Theory

   John M. Martyn🇺🇸 · Khadijeh Najafi🇺🇸 · Di Luo🇺🇸

   Physicists dating back to Feynman have lamented the difficulties of applying the variational principle to quantum field theories. In non-relativistic quantum field theories, the challenge is to parameterize and optimize over the infinitely many $n$-particle wave functions comprising the state's Fock space representation. Here we approach this problem by introducing neural-network quantum field states, a deep learning ansatz that enables application of the variational principle to non-relativistic quantum field theories in the continuum. Our ansatz uses the Deep Sets neural network architecture to simultaneously parameterize all of the $n$-particle wave functions comprising a quantum field state. We employ our ansatz to approximate ground states of various field theories, including an inhomogeneous system and a system with long-range interactions, thus demonstrating a powerful new tool for probing quantum field theories.

   ↳ quant-phcond-mat.dis-nncond-mat.str-elhep-lat+1PRL(2023)·24 citations
6. 06*

   Electric strings in non-Abelian theories

   Tanmay Vachaspati🇺🇸

   We find electric string solutions in Yang-Mills-Higgs theory.

   ↳ hep-thhep-lathep-phPRD(2023)·6 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.