Doubly Heavy Tetraquarks and Baryons
TL;DR: In this paper, the experimental evidence from $B$ and charm factories has been accumulating for the existence of exotic hadronic quarkonia, narrow resonances which cannot be made from a quark and an antiquark.
Abstract: During the last three years strong experimental evidence from $B$ and charm factories has been accumulating for the existence of exotic hadronic quarkonia, narrow resonances which cannot be made from a quark and an antiquark. Their masses and decay modes show that they contain a heavy quark-antiquark pair, but their quantum numbers are such that they must also contain a light quark-antiquark pair. The theoretical challenge has been to determine the nature of these resonances. The main possibilities are that they are either "genuine tetraquarks", i.e. two quarks and two antiquarks within one confinement volume, or "hadronic molecules" of two heavy-light mesons. In the last few months there as been more and more evidence in favor of the latter. I discuss the experimental data and its interpretation and provide fairly precise predictions for masses and quantum numbers of the additional exotic states which are naturally expected in the molecular picture but have yet to be observed. In addition, I provide arguments in favor of the existence of an even more exotic state - a hypothetical deuteron-like bound state of two heavy baryons. I also consider "baryon-like" states $Q Q' \bar q\bar q'$, which if found will be direct evidence not just for near-threshold binding of two heavy mesons, but for genuine tetraquarks with novel color networks. I stress the importance of experimental search for doubly-heavy baryons in this context.
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TL;DR: In this paper, the authors investigated the production of in the bottomonium sector as molecular state and used the effective Lagrangian based on the heavy quark symmetry to explore the rescattering mechanism and calculate their production ratios.
Abstract: We investigate the production of in the process , where is assumed to be the counterpart of in the bottomonium sector as molecular state We use the effective Lagrangian based on the heavy quark symmetry to explore the rescattering mechanism and calculate their production ratios Our results have shown that the production ratios for are orders of with reasonable cutoff parameter range The sizeable production ratios may be accessible at the future experiments like forthcoming BelleII, which will provide important clues to the inner structures of the exotic state
12 citations
TL;DR: In this paper, the authors investigate the behavior of doubly heavy spin-$3/2$ baryons in cold nuclear matter and study the variations of the spectroscopic parameters of the ground state with respect to changes in the density of the nuclear medium.
Abstract: We investigate the behavior of the doubly heavy spin-$3/2$ baryons in cold nuclear matter. In particular, we study the variations of the spectroscopic parameters of the ground state ${\mathrm{\ensuremath{\Xi}}}_{Q{Q}^{\ensuremath{'}}}^{*}$ and ${\mathrm{\ensuremath{\Omega}}}_{Q{Q}^{\ensuremath{'}}}^{*}$ particles, with $Q$ and ${Q}^{\ensuremath{'}}$ being $b$ or $c$ quark, with respect to the changes in the density of the nuclear medium. We find the shifts on the parameters under question at saturation medium density compared to their vacuum values. It is observed that the parameters of the ${\mathrm{\ensuremath{\Xi}}}_{Q{Q}^{\ensuremath{'}}}^{*}$ states containing two heavy quarks and one up or down quark are affected by the medium, considerably. The parameters of the ${\mathrm{\ensuremath{\Omega}}}_{Q{Q}^{\ensuremath{'}}}^{*}$ states containing two heavy quarks and one strange quark, however, do not show any sensitivity to the density of the cold nuclear medium. We also discuss the variations of the vector self-energy at each channel with respect to the changes in the density. The negative shifts in the mass of ${\mathrm{\ensuremath{\Xi}}}_{Q{Q}^{\ensuremath{'}}}^{*}$ states due to nucleons in the medium can be used to study the doubly heavy baryons' interactions with the nucleons. The results obtained can also be used in analyses of the results of the future in-medium experiments.
7 citations
TL;DR: In this paper, the bottom tetraquarks in the diquark-antidiquark framework with the inclusion of spin hyperfine, spin-orbit and tensor components of the one gluon exchange interaction were studied.
Abstract: We have done the exploratory study of bottom tetraquarks ($[bq\bar b \bar q];{q\in u,d}$) in the diquark-antidiquark framework with the inclusion of spin hyperfine, spin-orbit and tensor components of the one gluon exchange interaction. Our focus here is on the $Y_b$(10890) and other exotic states in the bottom sector. We have predicted some of the bottom counterparts to the charm tetraquark candidates. Our present study shows that if $Z_b(10610)$ and $Z_b(10650)$ are diquark-diantiquark states then they have to be first radial excitations only and we have predicted $Z_b(10650)$ state as first radial excitation of tetraquark state $X_b$ (10.143-10.230). We have identified $X_b$ state with $J^{PC}= 1^{+-}/0^{++}$ as being the analogue of $Z_c(3900)$. An observation of the $X_b$ will provide a deeper insight into the exotic hadron spectroscopy and is helpful to unravel the nature of the states connected by the heavy quark symmetry. We particularly focus on the lowest P wave $[bq][\bar b\bar q]$ states with $J^{PC}=1^{--}$ by computing their leptonic, hadronic and radiative decay widths to predict the status of still controversial $Y_b$(10890) state. Apart from this, we have also shown here the possibility of mixing of P wave states. In the case of mixing of $1^{--}$ state with different spin multiplicities, we found that predicted masses of the mixed P states differ from $Y_b$(10890) state only by $\pm20$ MeV energy difference which can be helpful to resolve further the structure of $Y_b$(10890).
7 citations
TL;DR: In this article, the results of the CDF and D0 detectors for Run II are presented based on an integrated luminosity of ∼ 10 fb−1 for 1.96 TeV pp collisions, representing the full Tevatron Run II data sets.
Abstract: The CDF [1] and D0 [2] detectors for Run II are illustrated below. The results presented here are based on an integrated luminosity of ∼ 10 fb−1 for 1.96 TeV pp collisions, representing the full Tevatron Run II data sets which were taken from 20012011. Both the CDF and the D0 detectors have solenoidal magnetic fields of 1.4 Tesla and 1.9 Tesla respectively, and excellent lepton coverage, detection, identification, and
1 citations
Cites background from "Doubly Heavy Tetraquarks and Baryon..."
...It could be one of the 4 quark (tetraquark) states speculated on by Gell-Mann [10]; a loosely-bound B −K molecular state [11]; or a combination of bound di-quarks considered by Maiani, et al....
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TL;DR: In this paper , the authors investigate the production of $$X_b$$ and propose two kinds of meson loops of $$B, which are assumed to be a $$B {\bar{B}}^*$$.
Abstract: Abstract We investigate the production of $$X_b$$ X b in the process $$\Upsilon (5S,6S)\rightarrow \gamma X_b$$ Υ ( 5 S , 6 S ) → γ X b , where $$X_b$$ X b is assumed to be a $$B {\bar{B}}^*$$ B B ¯ ∗ molecular state. Two kinds of meson loops of $$B^{(*)}{\bar{B}}^{(*)}$$ B ( ∗ ) B ¯ ( ∗ ) and $$B_1^{\prime }{\bar{B}}^{(*)}$$ B 1 ′ B ¯ ( ∗ ) were considered. To explore the rescattering mechanism, we calculated the relevant branching ratios using the effective Lagrangian based on the heavy quark symmetry. The branching ratios for the $$\Upsilon (5S,6S) \rightarrow \gamma X_b$$ Υ ( 5 S , 6 S ) → γ X b were found to be at the orders of $$10^{-7} \sim 10^{-6}$$ 10 - 7 ∼ 10 - 6 . Such sizeable branching ratios might be accessible at BelleII, which would provide important clues to the inner structures of the exotic state $$X_b$$ X b .
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Tohoku University1, University of Zurich2, Lawrence Berkeley National Laboratory3, Stanford University4, College of William & Mary5, University of Genoa6, University of Urbino7, CERN8, Budker Institute of Nuclear Physics9, University of California, Irvine10, Cornell University11, Argonne National Laboratory12, ETH Zurich13, Tata Institute of Fundamental Research14, Hillsdale College15, Spanish National Research Council16, Ohio State University17, University of Notre Dame18, Kent State University19, University of California, San Diego20, University of California, Berkeley21, University of Minnesota22, University of Alabama23, University of Helsinki24, Los Alamos National Laboratory25, California Institute of Technology26, George Washington University27, Syracuse University28, Lawrence Livermore National Laboratory29, Oklahoma State University–Stillwater30, University of Washington31, Max Planck Society32, Boston University33, University of California, Los Angeles34, Royal Holloway, University of London35, Université Paris-Saclay36, Fermilab37, University of Pennsylvania38, University of Illinois at Urbana–Champaign39, University of Bristol40, University of Tokyo41, University of Delaware42, Carnegie Mellon University43, University of California, Santa Cruz44, Karlsruhe Institute of Technology45, Heidelberg University46, Florida State University47, Carleton University48, University of Mainz49, University of Edinburgh50, Brookhaven National Laboratory51, Durham University52, University of Lausanne53, Massachusetts Institute of Technology54, University of Southampton55, Nagoya University56, University of Oxford57, Northwestern University58, University of British Columbia59, Columbia University60, Lund University61, University of Sheffield62, University of California, Santa Barbara63, Iowa State University64, University of Alberta65, University of Cambridge66
TL;DR: The Particle Data Group's biennial review as mentioned in this paper summarizes much of particle physics, using data from previous editions, plus 2658 new measurements from 644 papers, and lists, evaluates, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons.
Abstract: This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2658 new measurements from 644 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 112 reviews are many that are new or heavily revised including those on Heavy-Quark and Soft-Collinear Effective Theory, Neutrino Cross Section Measurements, Monte Carlo Event Generators, Lattice QCD, Heavy Quarkonium Spectroscopy, Top Quark, Dark Matter, V-cb & V-ub, Quantum Chromodynamics, High-Energy Collider Parameters, Astrophysical Constants, Cosmological Parameters, and Dark Matter. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.
4,465 citations
TL;DR: In this article, the process e(+)e(-) -> pi(+)pi(-) J/psi at a center-of-mass energy of 4.260 GeV using a 525 pb(-1) data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider was studied.
Abstract: We study the process e(+)e(-) -> pi(+)pi(-) J/psi at a center-of-mass energy of 4.260 GeV using a 525 pb(-1) data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross section is measured to be (62.9 +/- 1.9 +/- 3.7) pb, consistent with the production of the Y(4260). We observe a structure at around 3.9 GeV/c(2) in the pi(+/-) J/psi mass spectrum, which we refer to as the Z(c)(3900). If interpreted as a new particle, it is unusual in that it carries an electric charge and couples to charmonium. A fit to the pi(+/-) J/psi invariant mass spectrum, neglecting interference, results in a mass of (3899.0 +/- 3.6 +/- 4.9) MeV/c(2) and a width of (46 +/- 10 +/- 20) MeV. Its production ratio is measured to be R = (sigma(e(+)e(-) -> pi(+/-) Z(c)(3900)(-/+) -> pi(+)pi(-) J/psi)/sigma(e(+)e(-) -> pi(+)pi(-) J/psi)) = (21.5 +/- 3.3 +/- 7.5)%. In all measurements the first errors are statistical and the second are systematic.
677 citations
TL;DR: The observation of two narrow structures in the mass spectra of the π(±)Υ(nS) and π (±)h(b)(mP) pairs that are produced in association with a single charged pion in Υ(5S) decays is reported.
Abstract: We report the observation of two narrow structures in the mass spectra of the pi(+/-) Y(nS) (n = 1, 2, 3) and pi(+/-) h(b)(mP) (m = 1, 2) pairs that are produced in association with a single charged pion in Y(5S) decays The measured masses and widths of the two structures averaged over the five final states are M-1 = (10 6072 +/- 20) MeV/c(2), Gamma(1) =(184 +/- 24) MeV, and M-2 = (10 6522 +/- 15) MeV/c(2), Gamma(2) = (115 +/- 22) MeV The results are obtained with a 1214 fb(-1) data sample collected with the Belle detector in the vicinity of the Y(5S) resonance at the KEKB asymmetric-energy e(+)e(-) collider
492 citations
TL;DR: The narrow charmonium state near 3872 MeV reported by the Belle Collaboration and confirmed by CDF lies almost exactly at the D 0 D ∗0 threshold as mentioned in this paper.
401 citations
TL;DR: E+e-→π+π-hc at center-of-mass energies from 3.90 to 4.42 GeV is studied by using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider and a distinct structure, referred to as Zc(4020), is observed in the π±hc mass spectrum.
Abstract: We study e(+)e(-) -> pi(+) pi(-)h(c) at center-of-mass energies from 3.90 to 4.42 GeV by using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross sections are measured at 13 energies and are found to be of the same order of magnitude as those of e(+)e(-) -> pi(+) pi(-) J/Psi but with a different line shape. In the pi(+/-)h(c) mass spectrum, a distinct structure, referred to as Z(c)(4020) is observed at 4. 02 GeV/c(2). The Z(c)(4020) carries an electric charge and couples to charmonium. A fit to the pi(+/-)h(c) invariant mass spectrum, neglecting possible interferences, results in a mass of (4022.9 +/- 0.8 +/- 2.7) MeV/c(2) and a width of (7.9 +/- 2.7 +/- 2.6) MeV for the Z(c)(4020), where the first errors are statistical and the second systematic. The difference between the parameters of this structure and the Z(c) (4025) observed in the D*(D) over bar* final state is within 1.5 sigma, but whether they are the same state needs further investigation. No significant Z(c)(3900) signal is observed, and upper limits on the Z(c)(3900) production cross sections in pi +/- h(c) at center-of-mass energies of 4.23 and 4.26 GeVare set.
377 citations