DOCSLIB.ORG

Study of Coherence and Mixedness in Meson and Neutrino Systems

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Study of Coherence and Mixedness in Meson and Neutrino Systems Eur. Phys. J. C (2019) 79:96 https://doi.org/10.1140/epjc/s10052-019-6609-7 Regular Article - Theoretical Physics Study of coherence and mixedness in meson and neutrino systems Khushboo Dixita, Javid Naikoob, Subhashish Banerjeec, Ashutosh Kumar Alokd Indian Institute of Technology Jodhpur, Jodhpur 342037, India Received: 1 December 2018 / Accepted: 17 January 2019 © The Author(s) 2019 Abstract We study the interplay between coherence and be put to use to understand quantum coherence [7]. Recently mixedness in meson and neutrino systems. The dynamics of a trade-off between mixedness and quantum coherence, from the meson system is treated using the generic decoherence the perspective of resource theory [8], inherent in the system model taking into account the decaying nature of the sys- was proposed in the form of a complementarity relation [9]. tem. Neutrino dynamics is studied in the context of three These studies have mostly been focused on quantum optical flavour oscillations within the framework of a decoherence systems from the perspective of quantum information. model recently used in the context of LSND (Liquid Scintil- In this work we revisit these issues in the context of inter- lator Neutrino Detector) experiment. For meson systems, the esting sub-atomic systems, viz. the K and B mesons that are decoherence effect is negligible in the limit of zero CP vio- copiously produced at the φ and B-factories, respectively lation. Interestingly, the average mixedness increases with and the neutrino system generated in reactors and acceler- time for about one lifetime of these particles. For neutrino ators. These particles mainly aim at probing higher order system, in the context of the model considered, the decoher- corrections to the Standard Model (SM) of particle physics ence effect is maximum for neutrino energy around 30 MeV. along with hunting for physics beyond the SM. The preci- Further, the effect of CP violating phase is found to decrease sion measurement at BaBar and Belle experiments confirmed (increase) the coherence in the upper 0 <δ<π(lower the Cabibbo–Kobayasshi–Maskawa (CKM) paradigm of the π<δ<2π) half plane. SM. The ongoing experiments at the Large Hadron Collider (LHC) and Belle II experiments will now look for the sig- nals of non standard CP (C stands for Charge Conjugation 1 Introduction whereas P stands for Parity) violating phases by very high precision measurements of various B decays. On the other The quest for understanding the diverse nature of quantum hand, the phenomena of neutrino oscillations is experimen- correlations has lead in recent times to a rethinking in terms tally well established and ongoing and future experimental of the most pristine adjective associated with quantumness, facilities in neutrino sector aim to resolve some unsolved viz., quantum coherence. Quantum coherence has been the problems such as observation of CP-violating phase in lep- subject of a lot of interest as a resource, having implications tonic sector and the mass hierarchy problem. to implementation of technology [1–3] as well as in studies These systems can also be used to study a number of related to nonclassicality under the action of general open fundamental issues in physics such as non-locality, entan- system effects [4]. The resource-driven viewpoint is aimed glement [10–21] as well as probing signatures of quantum at achieving a better understanding of the classical-quantum gravity like background fluctuations [22]. Further, these sys- boundary, in a mathematically rigorous fashion. Some of the tems are oscillating, unstable in nature and driven by weak well known measures of quantum coherence are those based interactions in contrast to the usual systems used in quantum on relative entropy [2,5] and skew-information [6]. Further, information processing which are basically stable and gov- it has been recently shown that measures of entanglement can erned by the electromagnetic interactions. Neutrinos are also weakly interacting and stable particles, showing oscillating a e-mail: [email protected] behavior. Thus, the blend of all these makes these systems b e-mail: [email protected] unique and interesting for the study of fundamental issues. c e-mail: [email protected] In [23], a subtle spilloff of the concept of wave-particle d e-mail: [email protected] duality was brought out by the introduction of the concepts 0123456789().: V,-vol 123 96 Page 2 of 7 Eur. Phys. J. C (2019) 79:96 1 of quantum marking and erasure. This was quantified, in |ψ(0)=√ |M M¯ −|MM¯ , (1) the language of interferometry, by the Englert–Greenberger– 2 Yasinrelation[24,25] which expressed a trade-off between the fringe visibility, a wave like nature, and path distinguisha- where the first (second) particle in each ket is the one fly- ¯ bility, a particle like nature. This is also known as the quan- ing off in the left (right) direction and |M and |M are tum erasure and has been investigated in the context of corre- flavour eigenstates. As can be seen from (1), the initial state of lated neutral kaons [26]. Along with coherence, an important the neutral meson system is a singlet (maximally entangled) aspect of quantum dynamics is mixing which quantifies the state. ability of the system of interest to retain its quantumness. The Hilbert space of a system of two correlated neutral Decaying systems are inherently open systems [17,22]. mesons, as in (1), is Hence, it becomes relevant to understand the trade-off H = (H ⊕ H ) ⊗ (H ⊕ H ), (2) between coherence and mixing in these decaying meson sys- L 0 R 0 tems. In this work we study the complementarity between where HL,R are the Hilbert spaces of the left-moving and coherence and mixing in these oscillating unstable systems, right-moving decay products, each of which can be either a driven by weak interactions, using the generic decoherence meson or an anti-meson, and H0 is that of the zero-particle model. We study how these are dependent on the decoherence (vacuum) state. Thus, the total Hilbert space is the tensor parameter, decay width and CPviolation, which is one of the sum of a two-particle space, two one-particle spaces, and important criterion to explain the present matter anti-matter one zero-particle state. The initial density matrix of the full asymmetry of the universe. system is To undertake a similar study for neutrinos, we incorpo- rate decoherence effects (possibly) due to quantum gravity ρH (0) =|ψ(0)ψ(0)| . (3) like fluctuations in neutrino system, using the formalism of [27,28]. This was constructed to explain the LSND (a short baseline accelerator neutrino experiment) data which could The system, initially in the two-particle subspace, evolves not be described by usual three flavour neutrino oscillation in time into the full Hilbert space, eventually (after the decay phenomena. We have also studied the CP-violating effects in of both particles) finding itself in the vacuum state. As can be this system. appreciated from basic notions of quantum correlations such The paper is organized as follows. In Sect. 2, we discuss as entanglement, we need to project from the full Hilbert H H ⊗ H the dynamics of meson and neutrino system. The unstable space down to the two-particle sector L R.This ρ ( ) meson system is describe in the language of open quantum is easily done once H t is written in the operator-sum systems. In Sect. 3, we give a brief account of the measures representation [17,22,29]. The result is of quantum coherence and mixedness. Section 4 is devoted ⎛ ⎞ | |4 − 2 to results and their discussion. We conclude in Sect. 5. r a− 00 r a− ⎜ ⎟ ⎜ 0 a+ −a+ 0 ⎟ ρ(t) = A ⎝ ⎠ , (4) 0 −a+ a+ 0 ∗ −r 2a− 00 a− 2 System dynamics = ( 2λt ± )( ± δ ) = ( − δ )/ ( 2λt − δ2 ) where a± e 1 1 L , A 1 L 4 e L , 2 In this section, we briefly discuss the dynamics of the meson δL = 2Re(ε)/(1+|ε| ) and r = (1+ε)/(1−ε). ρ(t), which and neutrino system. The former being a decaying system, is written in the basis {|MM , |M M¯ , |MM¯ , |M¯ M¯ },is is treated as an open quantum system, leading to a generic trace-preserving. Here ε is a small CP-violating parame- description of decoherence in this system. Neutrino dynamics ter [30]. It is of order ∼ 10−3 for K mesons and 10−5 for is studied in the context of three flavour oscillations within Bd,s mesons. λ is the decoherence parameter, representing the framework of a decoherence model recently used in the interaction between the one-particle system and its environ- context of LSND experiment. ment which could be ascribed to quantum gravity effects Meson.FortheB system, imagine the decay Υ → bb¯ [31–40]. Some quantum gravity models are characterized by followed by hadronization into a B B¯ pair. In the Υ rest frame, quantum fluctuations of space-time geometry, such as micro- the mesons fly off in opposite directions (left and right, say); scopic black holes, giving rise to quantum space-time foam since the Υ is a spin-1 particle, they are in an antisymmetric backgrounds and hence may lead to decoherence. A stochas- spatial state. The same considerations apply to the K system, tic fluctuation of point-like solitonic structure, known as D- with the Υ replaced by a φ meson. particles, can constitute an environment for matter propaga- The flavour-space wave function of the correlated M M¯ tion [35,36]. Further, if the ground state of quantum gravity meson systems (M = K, Bd , Bs) at the initial time t = 0is consists of stochastically-fluctuating metrics, it can lead to 123 Eur.
Load more

Recommended publications
  • Mass Shift of Σ-Meson in Nuclear Matter
    Mass shift of σ-Meson in Nuclear Matter J. R. Morones-Ibarra, Mónica Menchaca Maciel, Ayax Santos-Guevara, and Felipe Robledo Padilla. Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, Ciudad Universitaria, San Nicolás de los Garza, Nuevo León, 66450, México. Facultad de Ingeniería y Arquitectura, Universidad Regiomontana, 15 de Mayo 567, Monterrey, N.L., 64000, México. April 6, 2010 Abstract The propagation of sigma meson in nuclear matter is studied in the Walecka model, assuming that the sigma couples to a pair of nucleon-antinucleon states and to particle-hole states, including the in medium effect of sigma-omega mixing. We have also considered, by completeness, the coupling of sigma to two virtual pions. We have found that the sigma meson mass decreases respect to its value in vacuum and that the contribution of the sigma omega mixing effect on the mass shift is relatively small. Keywords: scalar mesons, hadrons in dense matter, spectral function, dense nuclear matter. PACS:14.40;14.40Cs;13.75.Lb;21.65.+f 1. INTRODUCTION The study of matter under extreme conditions of density and temperature, has become a very important issue due to the fact that it prepares to understand the physics for some interesting subjects like, the conditions in the early universe, the physics of processes in stellar evolution and in heavy ion collision. Particularly, the study of properties of mesons in hot and dense matter is important to understand which could be the signature for detecting the Quark-Gluon Plasma (QGP) state in heavy ion collision, and to get information about the signal of the presence of QGP and also to know which symmetries are restored [1].
    [Show full text]
  • Phenomenology of Gev-Scale Heavy Neutral Leptons Arxiv:1805.08567
    Prepared for submission to JHEP INR-TH-2018-014 Phenomenology of GeV-scale Heavy Neutral Leptons Kyrylo Bondarenko,1 Alexey Boyarsky,1 Dmitry Gorbunov,2;3 Oleg Ruchayskiy4 1Intituut-Lorentz, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands 2Institute for Nuclear Research of the Russian Academy of Sciences, Moscow 117312, Russia 3Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia 4Discovery Center, Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK- 2100 Copenhagen, Denmark E-mail: [email protected], [email protected], [email protected], [email protected] Abstract: We review and revise phenomenology of the GeV-scale heavy neutral leptons (HNLs). We extend the previous analyses by including more channels of HNLs production and decay and provide with more refined treatment, including QCD corrections for the HNLs of masses (1) GeV. We summarize the relevance O of individual production and decay channels for different masses, resolving a few discrepancies in the literature. Our final results are directly suitable for sensitivity studies of particle physics experiments (ranging from proton beam-dump to the LHC) aiming at searches for heavy neutral leptons. arXiv:1805.08567v3 [hep-ph] 9 Nov 2018 ArXiv ePrint: 1805.08567 Contents 1 Introduction: heavy neutral leptons1 1.1 General introduction to heavy neutral leptons2 2 HNL production in proton fixed target experiments3 2.1 Production from hadrons3 2.1.1 Production from light unflavored and strange mesons5 2.1.2
    [Show full text]
  • A Quark-Meson Coupling Model for Nuclear and Neutron Matter
    Adelaide University ADPT February A quarkmeson coupling mo del for nuclear and neutron matter K Saito Physics Division Tohoku College of Pharmacy Sendai Japan and y A W Thomas Department of Physics and Mathematical Physics University of Adelaide South Australia Australia March Abstract nucl-th/9403015 18 Mar 1994 An explicit quark mo del based on a mean eld description of nonoverlapping nucleon bags b ound by the selfconsistent exchange of ! and mesons is used to investigate the prop erties of b oth nuclear and neutron matter We establish a clear understanding of the relationship b etween this mo del which incorp orates the internal structure of the nucleon and QHD Finally we use the mo del to study the density dep endence of the quark condensate inmedium Corresp ondence to Dr K Saito email ksaitonuclphystohokuacjp y email athomasphysicsadelaideeduau Recently there has b een considerable interest in relativistic calculations of innite nuclear matter as well as dense neutron matter A relativistic treatment is of course essential if one aims to deal with the prop erties of dense matter including the equation of state EOS The simplest relativistic mo del for hadronic matter is the Walecka mo del often called Quantum Hadro dynamics ie QHDI which consists of structureless nucleons interacting through the exchange of the meson and the time comp onent of the meson in the meaneld approximation MFA Later Serot and Walecka extended the mo del to incorp orate the isovector mesons and QHDI I and used it to discuss systems like
    [Show full text]
  • Quark Diagram Analysis of Bottom Meson Decays Emitting Pseudoscalar and Vector Mesons
    Quark Diagram Analysis of Bottom Meson Decays Emitting Pseudoscalar and Vector Mesons Maninder Kaur†, Supreet Pal Singh and R. C. Verma Department of Physics, Punjabi University, Patiala – 147002, India. e-mail: [email protected], [email protected] and [email protected] Abstract This paper presents the two body weak nonleptonic decays of B mesons emitting pseudoscalar (P) and vector (V) mesons within the framework of the diagrammatic approach at flavor SU(3) symmetry level. Using the decay amplitudes, we are able to relate the branching fractions of B PV decays induced by both b c and b u transitions, which are found to be well consistent with the measured data. We also make predictions for some decays, which can be tested in future experiments. PACS No.:13.25.Hw, 11.30.Hv, 14.40.Nd †Corresponding author: [email protected] 1. Introduction At present, several groups at Fermi lab, Cornell, CERN, DESY, KEK and Beijing Electron Collider etc. are working to ensure wide knowledge of the heavy flavor physics. In future, a large quantity of new and accurate data on decays of the heavy flavor hadrons is expected which calls for their theoretical analysis. Being heavy, bottom hadrons have several channels for their decays, categorized as leptonic, semi-leptonic and hadronic decays [1-2]. The b quark is especially interesting in this respect as it has W-mediated transitions to both first generation (u) and second generation (c) quarks. Standard model provides satisfactory explanation of the leptonic and semileptonic decays but weak hadronic decays confronts serious problem as these decays experience strong interactions interferences [3-6].
    [Show full text]
  • Mass Generation Via the Higgs Boson and the Quark Condensate of the QCD Vacuum
    Pramana – J. Phys. (2016) 87: 44 c Indian Academy of Sciences DOI 10.1007/s12043-016-1256-0 Mass generation via the Higgs boson and the quark condensate of the QCD vacuum MARTIN SCHUMACHER II. Physikalisches Institut der Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen, Germany E-mail: [email protected] Published online 24 August 2016 Abstract. The Higgs boson, recently discovered with a mass of 125.7 GeV is known to mediate the masses of elementary particles, but only 2% of the mass of the nucleon. Extending a previous investigation (Schumacher, Ann. Phys. (Berlin) 526, 215 (2014)) and including the strange-quark sector, hadron masses are derived from the quark condensate of the QCD vacuum and from the effects of the Higgs boson. These calculations include the π meson, the nucleon and the scalar mesons σ(600), κ(800), a0(980), f0(980) and f0(1370). The predicted second σ meson, σ (1344) =|ss¯, is investigated and identified with the f0(1370) meson. An outlook is given on the hyperons , 0,± and 0,−. Keywords. Higgs boson; sigma meson; mass generation; quark condensate. PACS Nos 12.15.y; 12.38.Lg; 13.60.Fz; 14.20.Jn 1. Introduction adds a small additional part to the total constituent- quark mass leading to mu = 331 MeV and md = In the Standard Model, the masses of elementary parti- 335 MeV for the up- and down-quark, respectively [9]. cles arise from the Higgs field acting on the originally These constituent quarks are the building blocks of the massless particles. When applied to the visible matter nucleon in a similar way as the nucleons are in the case of the Universe, this explanation remains unsatisfac- of nuclei.
    [Show full text]
  • D MESON PRODUCTION in E+E ANNIHILATION* Petros-Afentoulis Rapidis Stanford Linear Accelerator Center Stanford University Stanfor
    SLAC-220 UC-34d (E) D MESON PRODUCTION IN e+e ANNIHILATION* Petros-Afentoulis Rapidis Stanford Linear Accelerator Center Stanford University Stanford, California 94305 June 1979 Prepared for the Department of Energy under contract number DE-AC03-76SF00515 Printed in the United States of America . Available from National Technical Information Service, U .S . Department of Commerce, 5285 Port Royal Road, Springfield, VA 22161 . Price : Printed Copy $6 .50 ; Microfiche $3 .00 . * Ph .D . dissertation . ABSTRACT The production of D mesons in e+e annihilation for the center-of- mass energy range 3 .7 to 7 .0 GeV has been studied with the MARK :I magnetic detector at the Stanford Positron Electron Accelerating Rings facility . We observed a resonance in the total cross-section for hadron production in e+e annihilation at an energy just above the threshold for charm production. This resonance,which we name I", has a mass of 3772 ± 6 MeV/c 2 , a total width of 28 ± 5 MeV/c 2 , a partial width to electron pairs of 345 ± 85 eV/c 2 , and decays almost exclusively into DD pairs . The •" provides a rich source of background-free and kinematically well defined D mesons for study . From the study of D mesons produced in the decay of the *" we have determined the masses of the D ° and D+ mesons to be 1863 .3 ± 0 .9 MeV/c 2 and 1868 .3 ± 0 .9 MeV/c 2 respectively . We also determined the branching fractions for D ° decay to K-7r+ , K°ir+e and K 1r+ur ir+ to be (2 .2 ± 0 .6)%, (4 .0 ± 1 .3)%, and (3 .2 ± 1 .1)% and the r+i+ + branching fractions for D + decay to K°7+ and K to be (1 .5 0 .6)1 and (3 .9 '~ 1 .0)% .
    [Show full text]
  • Chapter 16 Constituent Quark Model
    Chapter 16 Constituent Quark Model 1 Quarks are fundamental spin- 2 particles from which all hadrons are made up. Baryons consist of three quarks, whereas mesons consist of a quark and an anti-quark. There are six 2 types of quarks called “flavours”. The electric charges of the quarks take the value + 3 or 1 (in units of the magnitude of the electron charge). − 3 2 Symbol Flavour Electric charge (e) Isospin I3 Mass Gev /c 2 1 1 u up + 3 2 + 2 0.33 1 1 1 ≈ d down 3 2 2 0.33 − 2 − ≈ c charm + 3 0 0 1.5 1 ≈ s strange 3 0 0 0.5 − 2 ≈ t top + 3 0 0 172 1 ≈ b bottom 0 0 4.5 − 3 ≈ These quarks all have antiparticles which have the same mass but opposite I3, electric charge and flavour (e.g. anti-strange, anti-charm, etc.) 16.1 Hadrons from u,d quarks and anti-quarks Baryons: 2 Baryon Quark content Spin Isospin I3 Mass Mev /c 1 1 1 p uud 2 2 + 2 938 n udd 1 1 1 940 2 2 − 2 ++ 3 3 3 ∆ uuu 2 2 + 2 1230 + 3 3 1 ∆ uud 2 2 + 2 1230 0 3 3 1 ∆ udd 2 2 2 1230 3 3 − 3 ∆− ddd 1230 2 2 − 2 113 1 1 3 Three spin- 2 quarks can give a total spin of either 2 or 2 and these are the spins of the • baryons (for these ‘low-mass’ particles the orbital angular momentum of the quarks is zero - excited states of quarks with non-zero orbital angular momenta are also possible and in these cases the determination of the spins of the baryons is more complicated).
    [Show full text]
  • 8. Quark Model of Hadrons Particle and Nuclear Physics
    8. Quark Model of Hadrons Particle and Nuclear Physics Dr. Tina Potter Dr. Tina Potter 8. Quark Model of Hadrons 1 In this section... Hadron wavefunctions and parity Light mesons Light baryons Charmonium Bottomonium Dr. Tina Potter 8. Quark Model of Hadrons 2 The Quark Model of Hadrons Evidence for quarks The magnetic moments of proton and neutron are not µN = e~=2mp and 0 respectively ) not point-like Electron-proton scattering at high q2 deviates from Rutherford scattering ) proton has substructure Hadron jets are observed in e+e− and pp collisions Symmetries (patterns) in masses and properties of hadron states, \quarky" periodic table ) sub-structure Steps in R = σ(e+e− ! hadrons)/σ(e+e− ! µ+µ−) Observation of cc¯ and bb¯ bound states and much, much more... Here, we will first consider the wave-functions for hadrons formed from light quarks (u, d, s) and deduce some of their static properties (mass and magnetic moments). Then we will go on to discuss the heavy quarks (c, b). We will cover the t quark later... Dr. Tina Potter 8. Quark Model of Hadrons 3 Hadron Wavefunctions Quarks are always confined in hadrons (i.e. colourless states) Mesons Baryons Spin 0, 1, ... Spin 1/2, 3/2, ... Treat quarks as identical fermions with states labelled with spatial, spin, flavour and colour. = space flavour spin colour All hadrons are colour singlets, i.e. net colour zero qq¯ 1 Mesons = p (rr¯+ gg¯ + bb¯) colour 3 qqq 1 Baryons = p (rgb + gbr + brg − grb − rbg − bgr) colour 6 Dr. Tina Potter 8.
    [Show full text]
  • Dark Matter Searches for Monoenergetic Neutrinos Arising from Stopped Meson Decay in the Sun
    UH511-1249-15 CETUP2015-020 Prepared for submission to JCAP Dark Matter Searches for Monoenergetic Neutrinos Arising from Stopped Meson Decay in the Sun Carsten Rotta Seongjin Ina Jason Kumarb David Yaylalic;d aDepartment of Physics, Sungkyunkwan University, Suwon 440-746, Korea bDepartment of Physics & Astronomy, University of Hawai'i, Honolulu, HI 96822, USA cDepartment of Physics, University of Arizona, Tucson, AZ 85721, USA dDepartment of Physics, University of Maryland, College Park, MD 20742, USA E-mail: [email protected], [email protected], [email protected], [email protected] Abstract. Dark matter can be gravitationally captured by the Sun after scattering off solar nuclei. Annihilations of the dark matter trapped and accumulated in the centre of the Sun could result in one of the most detectable and recognizable signals for dark mat- ter. Searches for high-energy neutrinos produced in the decay of annihilation products have yielded extremely competitive constraints on the spin-dependent scattering cross sections of dark matter with nuclei. Recently, the low energy neutrino signal arising from dark-matter annihilation to quarks which then hadronize and shower has been suggested as a competitive and complementary search strategy. These high-multiplicity hadronic showers give rise to a large amount of pions which will come to rest in the Sun and decay, leading to a unique sub- GeV neutrino signal. We here improve on previous works by considering the monoenergetic neutrino signal arising from both pion and kaon decay. We consider searches at liquid scin- arXiv:1510.00170v2 [hep-ph] 25 Nov 2015 tillation, liquid argon, and water Cherenkov detectors and find very competitive sensitivities for few-GeV dark matter masses.
    [Show full text]
  • LIGHT UNFLAVORED MESONS (S = C = B = 0) for I =1(Π, B, Ρ, A): Ud, (Uu Dd)/√2, Du; − for I =0(Η, Η′, H, H′, Ω, Φ, F , F ′): C1(U U + D D) + C2(S S)
    Citation: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018) and 2019 update LIGHT UNFLAVORED MESONS (S = C = B = 0) For I =1(π, b, ρ, a): ud, (uu dd)/√2, du; − for I =0(η, η′, h, h′, ω, φ, f , f ′): c1(u u + d d) + c2(s s) ± G P π I (J )=1−(0−) Mass m = 139.57061 0.00024 MeV (S = 1.6) ± 8 Mean life τ = (2.6033 0.0005) 10− s (S=1.2) cτ = 7.8045 m ± × [a] π± ℓ± ν γ form factors ± → ± FV = 0.0254 0.0017 F = 0.0119 ± 0.0001 A ± FV slope parameter a = 0.10 0.06 +0.009 ± R = 0.059 0.008 − π− modes are charge conjugates of the modes below. For decay limits to particles which are not established, see the section on Searches for Axions and Other Very Light Bosons. p + π DECAY MODES Fraction (Γi /Γ) Confidence level (MeV/c) µ+ ν [b] (99.98770 0.00004) % 30 µ ± µ+ ν γ [c] ( 2.00 0.25 ) 10 4 30 µ ± × − e+ ν [b] ( 1.230 0.004 ) 10 4 70 e ± × − e+ ν γ [c] ( 7.39 0.05 ) 10 7 70 e ± × − e+ ν π0 ( 1.036 0.006 ) 10 8 4 e ± × − e+ ν e+ e ( 3.2 0.5 ) 10 9 70 e − ± × − e+ ν ν ν < 5 10 6 90% 70 e × − Lepton Family number (LF) or Lepton number (L) violating modes µ+ ν L [d] < 1.5 10 3 90% 30 e × − µ+ ν LF [d] < 8.0 10 3 90% 30 e × − µ e+ e+ ν LF < 1.6 10 6 90% 30 − × − 0 G PC + π I (J )=1−(0 − ) Mass m = 134.9770 0.0005 MeV (S = 1.1) ± mπ mπ0 = 4.5936 0.0005 MeV ± − ± 17 Mean life τ = (8.52 0.18) 10− s (S=1.2) cτ = 25.5 nm ± × HTTP://PDG.LBL.GOV Page1 Created: 5/22/2019 10:04 Citation: M.
    [Show full text]
  • Search for Higgs Boson Decays to a Meson and a Photon
    Search for Higgs boson decays to a meson and a photon Konstantinos Nikolopoulos University of Birmingham on behalf of the ATLAS and CMS Collaborations Precision Workshop - Rencontres du Vietnam ATLAS experiment at CERN 26 September 2016, Quy Nhon, Vietnam This project has received funding from the European Union’s 7th Framework Programme for research, technological development and demonstration under grant agreement no 334034 (EWSB) Higgs Mechanism: Scalar Couplings Structure Higgs-fermion interactions: YukawaBosonic sector:couplings + V EWSB gives mass to W , W −, Z bosons H • Higgs interactions to vector bosons: defined by symmetryHiggs breaking couplings proportional to m2 gHV V • W /Z Higgs interactions to fermions: ad-hoc hierarchical Yukawa couplings∝mf 2m2 g = V V HVV v Higgs Mechanism: Scalar Couplings Structure Fermionic sector: Bosonic sector: f + V EWSB gives mass to W , W −, Z bosons H After introducting Higgs field, can add • H • Higgs couplings proportional to m2 gHV V gHff¯ Yukawa terms to Lagrangian • W /Z 2 m Higgs couplings proportional to fermion mass 2 2mV f • 2mV ghV V = V ghff¯ = f¯ gHVV = υ υ mf v gHf f¯ = Yf = v Fermionic sector: v is Higgs field vacuum expectation value f • After introducting Higgs field, can add Loops (e.g. γ,gluon)sensitivetoBSMphysics H • Yukawa couplings not imposed• by fundamental principle gHff¯ Yukawa terms to Lagrangian Higgs couplings Enhanced proportional Yukawa to fermion couplings mass in BSM scenarios • 4of39 ¯ [Phys. Rev. D80, 076002, Phys. Lett. B665 (2008) 79, Phys.Rev. D90 (2014) 115022,…] f mf Unitarityg ¯ = Y = bounds (through EFT) for fermion mass Hf f f v generation scale (1st/2nd generation) v is Higgs field vacuum expectation value • Loops (e.g.
    [Show full text]
  • The Quark Model
    Lecture The Quark model WS2018/19: ‚Physics of Strongly Interacting Matter‘ 1 Quark model The quark model is a classification scheme for hadrons in terms of their valence quarks — the quarks and antiquarks which give rise to the quantum numbers of the hadrons. The quark model in its modern form was developed by Murray Gell-Mann - american physicist who received the 1969 Nobel Prize in physics for his work on the theory of elementary particles. * QM - independently proposed by George Zweig 1929 .Hadrons are not ‚fundamental‘, but they are built from ‚valence quarks‘, i.e. quarks and antiquarks, which give the quantum numbers of the hadrons | Baryon | qqq | Meson | qq q= quarks, q – antiquarks 2 Quark quantum numbers The quark quantum numbers: . flavor (6): u (up-), d (down-), s (strange-), c (charm-), t (top-), b(bottom-) quarks anti-flavor for anti-quarks q: u, d, s, c, t, b . charge: Q = -1/3, +2/3 (u: 2/3, d: -1/3, s: -1/3, c: 2/3, t: 2/3, b: -1/3 ) . baryon number: B=1/3 - as baryons are made out of three quarks . spin: s=1/2 - quarks are the fermions! . strangeness: Ss 1, Ss 1, Sq 0 for q u, d, c,t,b (and q) charm: . Cc 1, Cc 1, Cq 0 for q u, d, s,t,b (and q) . bottomness: Βb 1, Bb 1, Bq 0 for q u, d, s,c,t (and q) . topness: Tt 1, Tt 1, Tq 0 for q u, d, s,c,b (and q) 3 Quark quantum numbers The quark quantum numbers: hypercharge: Y = B + S + C + B + T (1) (= baryon charge + strangeness + charm + bottomness +topness) .
    [Show full text]