DOCSLIB.ORG

Dark Matter Searches at BABAR

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Dark Matter Searches at BABAR A decade of dark sector and light dark matter searches at BABAR Bertrand Echenard Caltech on behalf of the BABAR collaboration Light Dark World 2020 – virtual Sydney Dark sectors in a nutshell What are dark sectors (or hidden sectors) • New particle(s) that don’t couple directly to the SM. Also referred to as feebly interacting particles • Indirect HS-SM interactions through portals: vector, scalar and neutrino portals at lowest order (see next slide) • Theoretically motivated: many BSM scenarios (e.g. EWSB) and string theory include dark sectors • Could have rich structure (SM structure is non-trivial) S,H,a A’, • Realized that MeV-GeV dark sector have very desirable properties: mediators light dark matter candidate, explanation of CP anomaly (axion), neutrino mass (heavy neutral lepton), … Dark Fermions ? Dark Forces Dark Higgs Dark matter could be part of a dark sector • Dark matter could reside in the dark sector, or mediate the SM-DS Dark Matter interactions Motivates broad exploration of light dark sector – not just limited to dark matter Low energy, high intensity e+e- colliders offer an ideal environment to study them Bertrand Echenard - LDW 2020 - p.2 The portals There are a few indirect interactions allowed by Standard Model symmetries between the dark sector and the SM – the “portals”. The lowest dimensional portals include: γ Vector New gauge boson A’ (dark photon) mixing A’ ε µν with SM photon/Z via kinetic mixing ε Dim=4 B A’µν φ H Scalar New dark scalar φ mixing with SM Higgs 2 µφ λφ2 Dim=4 H ( + ) 4 Fermion New heavy neutral lepton mixing with left- N ν Dim= yHNL handed SM doublets and the Higgs boson γ Axion New axion / axion-like particle coupling to a ~ ~ ∂ µ Dim=5 1/fa(c1tr(GG) + c2FF + c3 µj ) a gauge and fermion fields γ And many variations with slightly different couplings (note: small variations can have big phenomenological impacts) Bertrand Echenard - LDW 2020 - p.3 Light thermal dark matter Freeze-out scenario with light dark matter (χ) requires new light mediator to explain the relic density, or dark matter is overproduced χ < > ~ ( ) ϕ SM ≫ gD gSM SM χ ~ since (1) <> ≤ <> ≤ What kind of mediator? Must be neutral under the SM and renormalizable. Among the simplest choices: New scalar (φ) with Higgs coupling New vector (A’) with photon coupling χ χ φ H SM A’ γ SM χ χ SM SM Naturally realized in the context of dark sectors Focus on vector portal, much less constrained than the scalar one Bertrand Echenard - LDW 2020 - p.4 Light thermal dark matter Secluded annihilation Direct annihilation χ ∝ A’ ∝ ∝ gD χ gD annihilation Dark matter A’ = / mA’ mχ 2mχ f + f + A’ A’ A’ χ decay f - f - χ Dark photon Dark photon Visible decay Invisible decay Prompt or displaced decay Missing … Resonance feature … mass … energy … momentum Bertrand Echenard - LDW 2020 - p.5 Light thermal dark matter Thermal freeze-out DM with vector portal (direct annihilation) • Light DM can annihilate into SM particles via dark photon mediator mA’ > mDM • Thermal relic density uniquely predicted from DM mass and spin: < > ~ ~ Dimensionless = Toro & Krnjaic variable α Conservative assumptions ( D = 0.5 and • Dark matter must be a scalar, Dirac mA/mχ = 3) made for plotting constraints fermion or pseudo-fermion to satisfy from missing mass / momentum / energy CMB constraints experiments. Definitive predictions (targets) as a function of mass and particle type !!! Bertrand Echenard - LDW 2020 - p.6 Experimental approaches Missing energy / momentum Beam dump Colliders σ ∼ ε2 σ ∼ 2 ε2 2 σ ∼ α ε4 /s mA<<s Z / mA D 2 2 σ ∼ ε /(s-mA ) mA ~ s Large production yield for Probe dark sector coupling Large production low mediator masses yield on resonance (“high mass”) Large “detection yield” Process suppressed by ε4 Explore many final states Collider ideally suited to explore “high mass” region and structure of dark sector Bertrand Echenard - LDW 2020 - p.7 The BABAR experiment BABAR collected ∼500 fb-1 around the ϒ(4S), ϒ(3S) and ϒ(2S) resonances between 1999 - 2008 The BABAR detector ECM ∼10.5 GeV (at Y(4S)) Collaboration is still active more than 10 years after data taking ended ! Bertrand Echenard - LDW 2020 - p.8 Wide program at BABAR Extensive “dark sector” program conducted at BABAR over the last decade Search for dark photon Search for self-interacting DM + - → γ → + - µ+µ- + - + - e e A' , A' e e , e e → YD → A’A’A’ → 3X X (X=l,π) e+e- → γ A' , A' → invisible Search for axion (prel. results) Search for “muonic dark force” B→ Ka, a → γγ e+e- → µ+µ- Z' , Z' → µ+µ- Search for B-Mesogenesis Search for dark bosons B → Baryon + DM (+mesons) e+e- → γ A' → W' W'' Search for dark Higgs boson Exploratory search for dark hadrons + - e e → h' A' , h' → A' A' + - + - + - e e → πD + X, πD → e e , µ µ Search for leptophilic dark scalar + - → τ+τ- → µ+µ- e e h' , h' Related searches Search for six-quark dark matter Search for long-lived particles Y(2S,3S) → ΛΛ S Search for low-mass Higgs boson Published On-going /exploratory studies Bertrand Echenard - LDW 2020 - p.9 In this talk We will review the various searches performed at BABAR following the different type of dark sector particle and the “complexity” of the models. Dark bosons Dark photon (visible and invisible) Generic dark gauge boson Muonic dark force Dark scalars Dark Higgs boson Leptophilic dark scalar Axion Axion in B decays Dark matter Six-quark dark matter Bertrand Echenard - LDW 2020 - p.10 DARK BOSON DARK PHOTON & OTHER GAUGE BOSONS Visible dark photon decays Dilepton mass distributions A dark photon can be produced in e+e- → γ A’, A’ → e+e-, µ+µ- BABAR e+ e+ γ γ + + - l l e A’ e- εe - + - l l- e e m(e+e-) (GeV) Search for a narrow resonance over large QED background: BABAR • 2 tracks + 1 photon • Constrained fit (beam energy + vertex) • Particle identification (e/mu) • Kinematic cuts to improve purity µ+µ- • Quality cuts on tracks and photons mred (GeV) Bertrand Echenard - LDW 2020 - p.12 Visible dark photon decays Signal significance A dark photon can be produced in e+e- → γ A’, A’ → e+e-, µ+µ- e+e- e+ e+ BABAR γ γ + + - l l e A’ e- εe - l l- Search for a narrow resonance over large + - QED background: µ µ BABAR • 2 tracks + 1 photon BABAR • Constrained fit (beam energy + vertex) • Particle identification (e/mu) • Kinematic cuts to improve purity • Quality cuts on tracks and photons No significant signal found Bertrand Echenard - LDW 2020 - p.13 Visible dark photon decays Limits on kinetic mixing parameter A dark photon can be produced in (90% CL) over a wide range of masses e+e- → γ A’, A’ → e+e-, µ+µ- e+ e+ γ γ + + - l l e A’ e- ε e l- - l 2014 PRL 113 (2014) 201801 and PRL viewpoint Search for a narrow resonance over large QED background: • 2 tracks + 1 photon 2020 • Constrained fit (beam energy + vertex) • Particle identification (e/mu) • Kinematic cuts to improve purity • Quality cuts on tracks and photons 1901.09966 Worldwide program to extend coverage Bertrand Echenard - LDW 2020 - p.14 Visible dark photon decays Ilten et al., JHEP 06 (2018) 004 Alternative dark photon couplings Extensions of these portals can be constructed by gauging accidental symmetries of the SM or individual flavor numbers, e.g. • vector coupling to B−L current • a leptophobic B boson coupling directly to baryon number • vector mediating protophobic force • Vector coupling to Li-Lj i,j=e,µ,τ Constraints can be significantly weakened depending on the model → need multiple measurement to cover all bases Bertrand Echenard - LDW 2020 - p.15 Invisible dark photon decays At e+e- colliders, we can search for e+e- → γ A' , A' → invisible by tagging the recoil photon in “single photon” events BABAR collected ∼53 fb-1 of data with dedicated single photon triggers during its last year of data taking Analysis overview • Missing energy and momentum is best signature • Hermeticity is key, but need to allow some machine background • Search strategy: select single-photon final state, then look for a bump in missing mass mX (or Eγ) • Main backgrounds: e+e- → γγ and e+e- → γ e+e- with particles outside detector acceptance • Selection variable categories: photon quality, #tracks, extra Ecalorimeter, missing mass/energy and muon detector information Bertrand Echenard - LDW 2020 - p.16 Invisible dark photon decays At e+e- colliders, we can search for e+e- → γ A' , A' → invisible by tagging the recoil photon in “single photon” events BABAR collected ∼53 fb-1 of data with dedicated single photon triggers during its last year of data taking Signal significances BABAR Limit extraction procedure • Perform simultaneous fit to independent regions for each beam energy • Probe a total of 166 mass hypotheses • For each fit, fix background shape using the background control region, and float the signal yield, peaking and continuum background contributions • Most significant fit: local (global) significance of 3.1σ (2.6σ) BABAR Bertrand Echenard - LDW 2020 - p.17 Invisible dark photon decays At e+e- colliders, we can search for e+e- → γ A' , A' → invisible by tagging the recoil photon in “single photon” events BABAR collected ∼53 fb-1 of data with dedicated single photon triggers during its last year of data taking Limits on kinetic mixing (90% CL) Limits on kinetic mixing (90% CL) • Substantially improve previous limits in high mass region • Exclude purely invisible dark photon as explanation of “g-2” anomaly • Set constraints on light thermal freeze-out dark matter • Next generation B-factories should PRL 119, 131804 (2017) and PRL highlights substantially improve at high
Load more

Recommended publications
  • (2380) in a Hexaquark Scenario
    Proceedings of the 8th International Conference on Quarks and Nuclear Physics (QNP2018) Downloaded from journals.jps.jp by Deutsches Elek Synchrotron on 11/15/19 Proc. 8th Int. Conf. Quarks and Nuclear Physics (QNP2018) JPS Conf. Proc. 26, 022016 (2019) https://doi.org/10.7566/JPSCP.26.022016 The Properties of d∗(2380) in a Hexaquark Scenario Yubing Dong1;2;3;y, Pengnian Shen1;4, Fei Huang2, and Zongye Zhang1;2;3 1 Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China 2 School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 101408, China 3 Theoretical Physics Center for Science Facilities (TPCSF), CAS, Beijing 100049, China 4 College of Physics and Technology, Guangxi Normal University, Guilin 541004, China E-mail: [email protected] (Received January 5, 2019) The properties of the newly observed dibaryon resonance d∗(2380) (IJ p = 03+), calculated in a constituent chiral quark model, are briefly reported. Comparing to the available experimental data for its decays, we conclude that the resonance d∗(2380) can be reasonably interpreted as a compact heaxquark dominant state. KEYWORDS: d∗(2380), dibaryon, chiral constituent quark model, hexaquark 1. Introduction The history of the studies of dibaryon systems, like d∗, d0 and H particles, can be traced back to about half century ago (see the review article of Clement [1]). The clear experimental evidence for the d∗ was not observed until 2009. They were the CELSIUS/WASA and WASA@COSY collaborations, who carried out the study of ABC effect [2–5], and found that their measurements cannot be simply explained by the contribution either from the intermediate Roper excitation or from the t-channel ∆∆ contribution, except introducing an intermediate new resonance.
    [Show full text]
  • Diffractive Dissociation of Alpha Particles As a Test of Isophobic Short-Range Correlations Inside Nuclei ∗ Jennifer Rittenhouse West A, , Stanley J
    Physics Letters B 805 (2020) 135423 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb Diffractive dissociation of alpha particles as a test of isophobic short-range correlations inside nuclei ∗ Jennifer Rittenhouse West a, , Stanley J. Brodsky a, Guy F. de Téramond b, Iván Schmidt c a SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94309, USA b Laboratorio de Física Teórica y Computacional, Universidad de Costa Rica, 11501 San José, Costa Rica c Departamento de Física y Centro Científico Tecnológico de Valparáiso-CCTVal, Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso, Chile a r t i c l e i n f o a b s t r a c t Article history: The CLAS collaboration at Jefferson Laboratory has compared nuclear parton distributions for a range Received 15 January 2020 of nuclear targets and found that the EMC effect measured in deep inelastic lepton-nucleus scattering Received in revised form 9 April 2020 has a strongly “isophobic” nature. This surprising observation suggests short-range correlations between Accepted 9 April 2020 neighboring n and p nucleons in nuclear wavefunctions that are much stronger compared to p − p or n − Available online 14 April 2020 n correlations. In this paper we propose a definitive experimental test of the nucleon-nucleon explanation Editor: W. Haxton of the isophobic nature of the EMC effect: the diffractive dissociation on a nuclear target A of high energy 4 He nuclei to pairs of nucleons n and p with high relative transverse momentum, α + A → n + p + A + X. The comparison of n − p events with p − p and n − n events directly tests the postulated breaking of isospin symmetry.
    [Show full text]
  • A New Possibility for Light-Quark Dark Matter 2
    A new possibility for light-quark Dark Matter M. Bashkanov Department of Physics, University of York, Heslington, York, Y010 5DD, UK E-mail: [email protected] D. P. Watts Department of Physics, University of York, Heslington, York, Y010 5DD, UK E-mail: [email protected] July 2019 Abstract. Despite many decades of study the physical origin of ”dark matter” in the Universe remains elusive. In this letter we calculate the properties of a completely new dark matter candidate - Bose-Einstein condensates formed from a recently discovered bosonic particle in the light-quark sector, the d∗(2380) hexaquark. In this first study, we show stable d∗(2380) Bose-Einstein condensates could form in the primordial early universe, with a production rate sufficiently large that they are a plausible new candidate for dark matter. Some possible astronomical signatures of such dark matter are also presented. Submitted to: J. Phys. G: Nucl. Phys. Introduction arXiv:2001.08654v1 [astro-ph.CO] 23 Jan 2020 The physical origin of dark matter (DM) in the universe is one of the key unsolved questions for physics and astronomy. There is strong indirect evidence for the existence of such matter[1] from measurements of cosmic primordial radiation, anomalies in the radial dependence of galactic rotational curves and gravitational lensing. Despite its apparently pivotal role in the universe the physical origin of DM remains unknown, with significant research focused on beyond standard model (yet currently undiscovered) particles such as axions, sterile neutrinos and weakly interacting massive particles (WIMPs)[1]. Recent advances in experimental searches have now eliminated significant fractions of the parameter space for WIMP candidates and the initial motivation as a full solution to the dark matter problem appears weaker.
    [Show full text]
  • Lattice QCD Study of the $ H $ Dibaryon Using Hexaquark and Two
    CERN-TH-2018-098, DESY 18-066, HIM-2018-02, MITP/18-030, TIFR/TH/18-12 Lattice QCD study of the H dibaryon using hexaquark and two-baryon interpolators A. Francis,1 J. R. Green,2 P. M. Junnarkar,3 Ch. Miao,4, 5 T. D. Rae,4 and H. Wittig4, 5 1Theoretical Physics Department, CERN, CH-1211 Geneva 23, Switzerland 2NIC, Deutsches Elektronen-Synchrotron, D-15738 Zeuthen, Germany 3Tata Institute of Fundamental Research (TIFR), 1 Homi Bhabha Road, Mumbai 400005. India. 4PRISMA Cluster of Excellence and Institut f¨urKernphysik, University of Mainz, Becher Weg 45, D-55099 Mainz, Germany 5Helmholtz Institute Mainz, University of Mainz, D-55099 Mainz, Germany (Dated: April 16, 2019) 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 ground state in comparison with the local operators. We also present results, in the rest frame, using a second method based on distillation to compute a hermitian matrix of correlators with bilocal operators at both the source and the sink. This method yields a much more precise and reliable determination of the ground-state energy.
    [Show full text]
  • Deciphering the Recently Discovered Tetraquark Candidates Around 6.9 Gev
    Eur. Phys. J. C (2021) 81:25 https://doi.org/10.1140/epjc/s10052-020-08818-7 Regular Article - Theoretical Physics Deciphering the recently discovered tetraquark candidates around 6.9 GeV Jacob Sonnenschein1,a, Dorin Weissman2,b 1 The Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv, Israel 2 Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan Received: 6 October 2020 / Accepted: 28 December 2020 © The Author(s) 2021 Abstract Recently a novel hadronic state of mass 6.9 GeV, or, using a second fitting model that decays mainly to a pair of charmonia, was observed in [ ( )]= ± ± LHCb. The data also reveals a broader structure centered M X 6900 6886 11 11 around 6490 MeV and suggests another unconfirmed reso- [X(6900)]=168 ± 33 ± 69 (1.2) nance centered at around 7240 MeV, very near to the thresh- The data also reveals a broader structure centered around old of two doubly charmed cc baryons. We argue in this note that these exotic hadrons are genuine tetraquarks and 6490 MeV, referred to as a “threshold enhancement” in [1], not molecules of charmonia. It is conjectured that they are and also suggests the existence of another resonance centered V-baryonium , namely, have an inner structure of a baryonic at around 7240 MeV,very near to the threshold of two doubly vertex with a cc diquark attached to it, which is connected by charmed cc baryons. See Fig. 1. The higher state, which we ( ) a string to an anti-baryonic vertex with a c¯c¯ anti-diquark.
    [Show full text]
  • Dark Matter, Symmetries and Cosmology
    UNIVERSITY OF CALIFORNIA, IRVINE Symmetries, Dark Matter and Minicharged Particles DISSERTATION submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in Physics by Jennifer Rittenhouse West Dissertation Committee: Professor Tim Tait, Chair Professor Herbert Hamber Professor Yuri Shirman 2019 © 2019 Jennifer Rittenhouse West DEDICATION To my wonderful nieces & nephews, Vivian Violet, Sylvie Blue, Sage William, Micah James & Michelle Francesca with all my love and so much freedom for your beautiful souls To my siblings, Marlys Mitchell West, Jonathan Hopkins West, Matthew Blake Evans Tied together by the thread in Marlys’s poem, I love you so much and I see your light To my mother, Carolyn Blake Evans, formerly Margaret Carolyn Blake, also Dickie Blake, Chickie-Dickie, Chickie D, Mimikins, Mumsie For never giving up, for seeing me through to the absolute end, for trying to catch your siblings in your dreams. I love you forever. To my father, Hugh Hopkins West, Papa-san, with all my love. To my step-pop, Robert Joseph Evans, my step-mum, Ann Wilkinson West, for loving me and loving Dickie and Papa-san. In memory of Jane. My kingdom for you to still be here. My kingdom for you to have stayed so lionhearted and sane. I carry on. Piggy is with me. In memory of Giovanni, with love and sorrow. Io sono qui. Finally, to Physics, the study of Nature, which is so deeply in my bones that it cannot be removed. I am so grateful to be able to try to understand. ... "You see I am absorbed in painting with all my strength; I am absorbed in color - until now I have restrained myself, and I am not sorry for it.
    [Show full text]
  • Pentaquark and Tetraquark States Arxiv:1903.11976V2 [Hep-Ph]
    Pentaquark and Tetraquark states 1 2 3 4;5 6;7;8 Yan-Rui Liu, ∗ Hua-Xing Chen, ∗ Wei Chen, ∗ Xiang Liu, y Shi-Lin Zhu z 1School of Physics, Shandong University, Jinan 250100, China 2School of Physics, Beihang University, Beijing 100191, China 3School of Physics, Sun Yat-Sen University, Guangzhou 510275, China 4School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China 5Research Center for Hadron and CSR Physics, Lanzhou University and Institute of Modern Physics of CAS, Lanzhou 730000, China 6School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China 7Collaborative Innovation Center of Quantum Matter, Beijing 100871, China 8Center of High Energy Physics, Peking University, Beijing 100871, China April 2, 2019 Abstract The past seventeen years have witnessed tremendous progress on the experimental and theo- retical explorations of the multiquark states. The hidden-charm and hidden-bottom multiquark systems were reviewed extensively in Ref. [1]. In this article, we shall update the experimental and theoretical efforts on the hidden heavy flavor multiquark systems in the past three years. Espe- cially the LHCb collaboration not only confirmed the existence of the hidden-charm pentaquarks but also provided strong evidence of the molecular picture. Besides the well-known XYZ and Pc states, we shall discuss more interesting tetraquark and pentaquark systems either with one, two, three or even four heavy quarks. Some very intriguing states include the fully heavy exotic arXiv:1903.11976v2 [hep-ph] 1 Apr 2019 tetraquark states QQQ¯Q¯ and doubly heavy tetraquark states QQq¯q¯, where Q is a heavy quark.
    [Show full text]
  • Neutrino Free Download
    NEUTRINO FREE DOWNLOAD Frank Close | 192 pages | 01 Apr 2012 | Oxford University Press | 9780199695997 | English | Oxford, United Kingdom What is a neutrino? Astroparticle Physics. Enhancing the basic framework to accommodate their mass is straightforward by adding a right-handed Lagrangian. Oneworld Publications. The coincidence of both events — positron annihilation and neutron capture — gives a unique signature of an antineutrino interaction. How do stars collapse and form supernovae? Bibcode : JPhCS. In Stanislav Mikheyev and Alexei Smirnov expanding on work by Neutrino Wolfenstein noted that flavour oscillations can be modified when neutrinos propagate through matter. Quantum gravity. The first pendulum is set in motion by the experimenter while the second begins at rest. When a neutrino hits the heavy water in the detector's spherical vessel, a cone of light--here clearly visible in red--spreads out to sensors Neutrino the device. Though widely reported in the media, the results were greeted with a great deal of skepticism from the scientific community. The smallest modification to the Standard Model, which only has Neutrino neutrinos, is to allow these left-handed neutrinos to Neutrino Majorana masses. Physical Review C. Categories : Astrophysics Elementary particles. Neutrino November Neutrino Main article: Seesaw mechanism. In all observations so far of leptonic processes despite extensive and continuing searches for exceptionsthere is Neutrino any change in overall lepton number; for example, if total lepton number is zero in the initial state, electron neutrinos appear in the final state together with only positrons anti-electrons or electron-antineutrinos, and electron antineutrinos with electrons or electron neutrinos. This marks the first use of neutrinos for communication, and Neutrino research may permit binary neutrino messages to be sent immense distances through even the densest Neutrino, such as the Earth's core.
    [Show full text]
  • “Unmatter,” As a New Form of Matter, and Its Related “Un-Particle,” “Un-Atom,” “Un-Molecule”
    “Unmatter,” as a new form of matter, and its related “un-particle,” “un-atom,” “un-molecule” Florentin Smarandache has introduced the notion of “unmatter” and related concepts such as “unparticle,” “unatom,” “unmolecule” in a manuscript from 1980 according to the CERN web site, and he uploaded articles about unmatter starting with year 2004 to the CERN site and published them in various journals in 2004, 2005, 2006. In short, unmatter is formed by matter and antimatter that bind together. The building blocks (most elementary particles known today) are 6 quarks and 6 leptons; their 12 antiparticles also exist. Then unmatter will be formed by at least a building block and at least an antibuilding block which can bind together. Keywords: unmatter, unparticle, unatom, unmolecule Abstract. As shown, experiments registered unmatter: a new kind of matter whose atoms include both nucleons and anti-nucleons, while their life span was very short, no more than 10-20 sec. Stable states of unmatter can be built on quarks and anti-quarks: applying the unmatter principle here it is obtained a quantum chromodynamics formula that gives many combinations of unmatter built on quarks and anti-quarks. In the last time, before the apparition of my articles defining “matter, antimatter, and unmatter”, and Dr. S. Chubb’s pertinent comment on unmatter, new development has been made to the unmatter topic in the sense that experiments verifying unmatter have been found.. 1. Definition of Unmatter. In short, unmatter is formed by matter and antimatter that bind together. The building blocks (most elementary particles known today) are 6 quarks and 6 leptons; their 12 antiparticles also exist.
    [Show full text]
  • A Strangeonium Hybrid Meson?
    Digital Collections @ Dordt Faculty Work Comprehensive List 8-12-2019 Is the Y (2175) a Strangeonium Hybrid Meson? Jason Ho Dordt University, [email protected] R. Berg University of Saskatchewan T. G. Steele University of Saskatchewan W. Chen Sun Yat-sen University D. Harnett University of the Fraser Valley Follow this and additional works at: https://digitalcollections.dordt.edu/faculty_work Part of the Physics Commons Recommended Citation Ho, J., Berg, R., Steele, T. G., Chen, W., & Harnett, D. (2019). Is the Y (2175) a Strangeonium Hybrid Meson?. Physical Review D, 100 (3), 034012. https://doi.org/10.1103/PhysRevD.100.034012 This Article is brought to you for free and open access by Digital Collections @ Dordt. It has been accepted for inclusion in Faculty Work Comprehensive List by an authorized administrator of Digital Collections @ Dordt. For more information, please contact [email protected]. Is the Y (2175) a Strangeonium Hybrid Meson? Abstract QCD Gaussian sum rules are used to explore the vector (JPC=1−−) strangeonium hybrid interpretation of the Y(2175). Using a two-resonance model consisting of the Y(2175) and an additional resonance, we find that the relative resonance strength of the Y(2175) in the Gaussian sum rules is less than 5% that of a heavier 2.9 GeV state. This small relative strength presents a challenge to a dominantly hybrid interpretation of the Y(2175). Keywords quantum chromodynamics, exotic mesons, hybrid mesons, mass Disciplines Physics Comments Access on publisher's site: https://journals.aps.org/prd/pdf/10.1103/PhysRevD.100.034012 This article is available at Digital Collections @ Dordt: https://digitalcollections.dordt.edu/faculty_work/1239 PHYSICAL REVIEW D 100, 034012 (2019) Is the Yð2175Þ a strangeonium hybrid meson? J.
    [Show full text]
  • Dr. Mikhail Bashkanov DEPARTMENT of PHYSICS COLLOQUIUM
    DEPARTMENT OF PHYSICS COLLOQUIUM Secret Life of Exotic Hadrons: from Lightest Systems to Neutron Stars Dr. Mikhail Bashkanov Edinburgh University Several new findings in the four, five and six quark systems reheat the interest in the field of multiquark states (beyond trivial �"� and ���). A lot of progress has recently been made in the 6� sector, on both the theoretical and experimental side. The d*(2380) hexaquark is the only multiquark state which can be produced copiously at current facilities, offering unique access to information beyond its basic quantum numbers, particularly its physical size, magnetic moment, quadrupole deformation and internal structure. Latest experiments on d* photoproduction provide new information on multiquark system dynamics. Neutron stars are other valuable laboratories to study the fundamental properties of dense nuclear/quark matter. Neutron star mergers, such as recently observed by LIGO with both electromagnetic and gravitational wave signals, have properties which depend strongly on the Equation of State. A number of exotic possibilities have been investigated as possible degrees of freedom within neutron stars. It was recently demonstrated that hexaquarks have the potential for major impact on the properties of the dense nuclear matter in neutron stars and during neutron star mergers. It will be shown that the properties of this nucleonic matter can be constrained by precision measurements of nuclei and nuclear reactions at ground based experiments. TIME:TIME: 3:454:00--4:455:00 pm,pm, Thursday, Thursday, FebruaryFebruary 22,1, 2018 2018 (refreshments: 3:303:45 pm in the hallway) PLACE: Bennhold Auditorium (room 101), Corcoran Hall, GWU 725 21st Street, NW, Washington, DC 20052 METRO STATION: GWU/FOGGY BOTTOM (BLUE, ORANGE & SILVER LINES).
    [Show full text]
  • Newsletter #3 April 2021
    Newsletter #3 April 2021 The STRONG-2020 project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 824093 Table of contents Table of contents ___________________________________________________________ 2 Foreword __________________________________________________________________ 3 The European Centre for Theoretical Studies in Nuclear Physics and related Areas (ECT*) _ 4 Parton Branching: a bridge from resummation to parton shower _____________________ 7 First precise measurement of the mass of a nucleus with a bound doubly strange baryon _ 9 Emergent hadron mass______________________________________________________ 11 The IWHSS 2020 workshop ___________________________________________________ 14 Theoretical aspects of Hadron Spectroscopy and phenomenology workshop __________ 15 EIC Yellow report release ____________________________________________________ 18 An interview with Anton Kononov _____________________________________________ 18 The STRONG-2020 Public Lecture Series ________________________________________ 20 The STRONG-2020 dedicated YouTube channel __________________________________ 21 STRONG-2020 supported INSPYRE 2021 ________________________________________ 23 Mosaic photo on the STRONG-2020 web page ___________________________________ 24 2 Foreword This is the third newsletter of the STRONG-2020 European project, which has been prepared by the Dissemination Board (DB) as editors, and contains a series of news and information of interest not only for the
    [Show full text]