DOCSLIB.ORG

Physics of Muonium and Muonium Oscillations

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Physics of Muonium and Muonium Oscillations Physics of muonium and muonium oscillations Alexey A. Petrov1 1Department of Physics and Astronomy Wayne State University, Detroit, MI 48201, USA Precision studies of a muonium, the bound state of a muon and an electron, provide access to physics beyond the Standard Model. We propose that extensive theoretical and experimental studies of atomic physics of a muonium, its decays and muonium-antimuonium oscillations could provide an impact on indirect searches for new physics. An especially clean system to study BSM effects in in the Standard Model at tree level, New Physics degrees lepton sector is muonium Mµ, a QED bound state of a of freedom can effectively compete with the SM parti- positively-charged muon and a negatively-charged elec- cles running in the loop graphs, making their discovery + − tron, jMµi ≡ jµ e i. The main decay channel of the possible. This is, of course, only true provided beyond state is driven by the weak decay of the muon. The av- the Standard Model (BSM) constructions include flavor- erage lifetime of a muonium state τMµ is thus expected violating interactions. In order to probe those we con- to be the same as that of the muon, τµ = (2:1969811 ± sider muonium decays and oscillations. −6 0:0000022) × 10 s [1], apart from the tiny effect due to Denoting the \muon quantum number" by Lµ, FCNC 2 2 2 −10 time dilation, (τMµ −τµ)/τµ = α me=(2mµ) = 6×10 . decays of a muonium would probe ∆Lµ = 1 interactions. Such a lifetime, in principle, is rather long to allow for The effective Lagrangian, L∆Lµ=1, can then be divided precision measurements of muonium's atomic and parti- eff into the dipole part, LD, and a part that involves four- cle physics properties [2]. In this Letter of Interest (LOI) fermion interactions. we will argue that a robust theoretical and experimental research program in muonium physics will help us better Leff = LD + L`q + :::: (1) understand both precision Standard Model (SM) physics and place competitive constraints on New Physics (NP) Here the ellipses denote effective operators that are not interactions. relevant for the following discussion. The dipole part in Eq. (1) is usually written as m h I. MUONIUM: ATOMIC PHYSICS L = − `1 C`1`2 ` σµν P ` D Λ2 DR 2 L 1 i `1`2 µν Muonium's structure is similar to that of a hydrogen + CDL `2σ PR`1 Fµν + h:c: ; (2) without the added complexity of a proton, both muon and electron are point-like, which helps in interpretation where PR;L = (1 ± γ5)=2 is the right (left) chiral projec- of atomic structure measurements. Just like a positron- tion operator. The Wilson coefficients would, in general, ium or a Hydrogen atom, muonium could be produced be different for different leptons `i. in two spin configurations, a spin-one triplet state called The four-fermion dimension-six lepton-quark La- ortho-muonium, and a spin-zero singlet state called para- grangian takes the form [5] muonium. Atomic calculations of muonium properties are impor- ∆L =1 1 X h L µ = − Cf µ γαe + Cf µ γαe jV tant and could be related to other systems. Measure- eff Λ2 VR R R VL L L α ments of its hyperfine splitting ∆ν , its Zeeman ef- f HFS fect, the 1s−2s frequency difference ∆ν could be use- f α q α A 1s2s + CAR µRγ eR + CAL µLγ eL jα ful in connection with similar computations in Hydrogen f f S without the complications of strong interactions and for + memf GF CSR µReL + CSL µLeR j (3) searches for New Physics. For example, the light-by-light f f P (LBL) contribution to the hyperfine splitting in muonium + memf GF CPR µReL + CPL µLeR j is similar to the LBL contribution to (g−2). A three-loop f αβ f αβ T i correction has recently been computed [3] with hadronic + memf GF CTR µRσ eL + CTL µLσ eR jαβ ; LBL scattering contribution computed earlier [4]. V A S P where jα = fγαf, jα = fγαγ5f, j = ff, j = fγ5f, T and jαβ = fσαβf are the fermion currents with f repre- II. MUONIUM: DECAYS senting fermions that are not integrated out at the the muonium scale. The subscripts on the Wilson coefficients Flavor-changing neutral current (FCNC) interactions are for the type of Lorentz structure: vector, axial-vector, serve as a powerful probe of physics beyond the standard scalar, pseudo-scalar, and tensor. The Wilson coefficients model (BSM). Since no local operators generate FCNCs would in general be different for different fermions f. 2 The effective Lagrangian of Eq. (1) could be probed ity improved by 2-3 orders of magnitude could exploit in muon decays such as µ ! eγ or µ ! 3e, etc. These the time evolution of the Mµ − M µ conversion process. decays receive contributions from many possible opera- Integrating over time and normalizing to Γ(Mµ ! f) tors in Eqs. (2) and (3), making it difficult to identify we get the probability of Mµ decaying as M µ at some the Lorentz structure of possible NP interactions. This time t > 0 [8], problem could be alleviated by studying decays with con- strained kinematics [5, 6]. Studying decays of para- and ortho-muonia M V ! e+e−, M V ! 3γ, and M P ! γγ Γ(Mµ ! f) µ µ µ P (Mµ ! M µ) = = RM (x; y): (6) will only select particular combinations of the operators Γ(Mµ ! f) in Eq. (3), making possible identification of NP interac- Using the data from [9] to place constraints on the oscil- tions. lation parameters, one must take into to account the fact that the set-up described in [9] had muonia propagating in a magnetic field B0. This magnetic field suppresses os- III. MUONIUM-ANTIMUONIUM cillations by removing degeneracy between Mµ and M µ. OSCILLATIONS It also has a different effect on different spin configura- tions of the muonium state and the Lorentz structure of In the presence of flavor-violating interactions muo- the operators that generate mixing [10{12]. Experimen- + − tally these effects could accounted for by introducing a nium jMµi ≡ jµ e i could oscillate into an antimuo- − + factor SB(B0). The oscillation probability is then [9], nium jM µi ≡ jµ e i state. While such processes are strongly suppressed by neutrino masses in the Standard −11 Model, plenty of BSM scenarios boast much larger tran- P (Mµ ! M µ) ≤ 8:3 × 10 =SB(B0): (7) sition rates [7]. A mere presence of ∆Lµ = 2 interac- tions leads to the fact that muonium flavor eigenstates A more thorough analysis of the effects of magnetic fields are no longer its mass eigenstates, leading to the time- would be desirable for better constraints on the oscillat- dependent oscillations of flavor states, and generation of ing parameters. the mass and lifetime splittings of its mass eigenstates, One can use Ref. [8] to relate x and y to the BSM scale which we denote ∆m and ∆Γ, respectively. Λ (or the Wilson coefficients Ci of BSM operators) and Denoting an amplitude for the muonium decay into a constrain their values from the experimental data. Since final state f as Af = hfjHjMµi and an amplitude for both spin-0 and spin-1 muonium states were produced its decay into a CP-conjugated final state f as Af¯ = in the experiment [9], one should average the oscillation hfjHjMµi, we can write the time-dependent decay rate probability over the number of polarization degrees of of Mµ into the f [8], freedom, 1 2 2 Γ(M ! f)(t) = N jA j e−Γt (Γt) R (x; y); (4) X 1 i i µ 2 f f M P (Mµ ! M µ)exp = P (Mµ ! M µ ); (8) 2Si + 1 i=P;V where Nf is a phase-space factor and RM (x; y) is the oscillation rate, where P (Mµ ! M µ)exp is the experimental oscillation 1 probability from Eq. (7).The values of SB(B0) are given R (x; y) = x2 + y2 ; (5) M 2 in Table II of [9]. As can be seen [8], even 20 year old ex- perimental data provide constraints on the New Physics where x = ∆M=ΓMµ and y = ∆Γ=2ΓMµ . Since ∆M scale that are comparable to those probed by the LHC and ∆Γ are dominated by New Physics interactions [8], program of the order Λ ∼ 5 TeV. An improvement of sen- while ΓMµ is given by the SM interactions, x; y 1. sitivity by two orders of magnitude will allow constraint Thus, oscillating functions can be expanded in x and y specific models of New Physics better then the combina- resulting in a power-law dependence displayed in Eq. (5). tions of other measurements. We urge our experimental The most recent experiment studying Mµ −M µ oscilla- colleagues to further study muonium-antimuonium oscil- tions was done in the 1990s [9], and was statistics limited lations. For this, a pulsed µ+ source could significantly by the available µ+ flux. It could not study the time- reduce the ratio of the potential M¯ signal to µ+ and M dependence of Eq. (4). A new experiment with sensitiv- decay related background [2]. [1] R. H. Bernstein and P. S. Cooper, \Charged Lepton Fla- Phys. Soc. Jap. 85, no.9, 091004 (2016) vor Violation: An Experimenter's Guide," Phys. Rept. [3] M. I. Eides and V. A. Shelyuto, \Muon Loop Light-by- 532, 27-64 (2013) Light Contribution to Hyperfine Splitting in Muonium," [2] K. P. Jungmann, \Precision Muonium Spectroscopy," J. Phys. Rev. Lett. 112, no.17, 173004 (2014) 3 [4] S.
Load more

Recommended publications
  • The Lamb Shift Experiment in Muonic Hydrogen
    The Lamb Shift Experiment in Muonic Hydrogen Dissertation submitted to the Physics Faculty of the Ludwig{Maximilians{University Munich by Aldo Sady Antognini from Bellinzona, Switzerland Munich, November 2005 1st Referee : Prof. Dr. Theodor W. H¨ansch 2nd Referee : Prof. Dr. Dietrich Habs Date of the Oral Examination : December 21, 2005 Even if I don't think, I am. Itsuo Tsuda Je suis ou` je ne pense pas, je pense ou` je ne suis pas. Jacques Lacan A mia mamma e mio papa` con tanto amore Abstract The subject of this thesis is the muonic hydrogen (µ−p) Lamb shift experiment being performed at the Paul Scherrer Institute, Switzerland. Its goal is to measure the 2S 2P − energy difference in µp atoms by laser spectroscopy and to deduce the proton root{mean{ −3 square (rms) charge radius rp with 10 precision, an order of magnitude better than presently known. This would make it possible to test bound{state quantum electrody- namics (QED) in hydrogen at the relative accuracy level of 10−7, and will lead to an improvement in the determination of the Rydberg constant by more than a factor of seven. Moreover it will represent a benchmark for QCD theories. The experiment is based on the measurement of the energy difference between the F=1 F=2 2S1=2 and 2P3=2 levels in µp atoms to a precision of 30 ppm, using a pulsed laser tunable at wavelengths around 6 µm. Negative muons from a unique low{energy muon beam are −1 stopped at a rate of 70 s in 0.6 hPa of H2 gas.
    [Show full text]
  • Muonium-Antimuonium Conversion Abstract
    SciPost Phys. Proc. 5, 009 (2021) Muonium-antimuonium conversion Lorenz Willmann? and Klaus Jungmann Van Swinderen Institute, University of Groningen, 9747 AA, Groningen, The Netherlands ? [email protected] Review of Particle Physics at PSI doi:10.21468/SciPostPhysProc.5 Abstract The MACS experiment performed at PSI in the 1990s provided an yet unchallenged upper bound on the probability for a spontaneous conversion of the muonium atom, + + M =(µ e−), into its antiatom, antimuonium M =(µ−e ). It comprises the culmination of a series of measurements at various accelerator laboratories worldwide. The experimen- tal limits on the process have provided input and steering for the further development of a variety of theoretical models beyond the standard theory, in particular for mod- els which address lepton number violating processes and matter-antimatter oscillations. Several models beyond the standard theory could be strongly disfavored. There is inter- est in a new measurement and improved sensitivity could be reached by exploiting the time evolution of the conversion process, e.g., at intense pulsed muonium sources. Copyright L. Willmann and K. Jungmann. Received 16-02-2021 This work is licensed under the Creative Commons Accepted 28-04-2021 Check for Attribution 4.0 International License. Published 06-09-2021 updates Published by the SciPost Foundation. doi:10.21468/SciPostPhysProc.5.009 9.1 Introduction + The bound state of a positive muon (µ ) and an electron (e−) is an exotic atom which has been named muonium (M) by V.Telegdi. This exotic atom was first produced and observed by V.W. Hughes and collaborators in 1960 [1].
    [Show full text]
  • Hadronic Light-By-Light Contribution to $(G-2) \Mu $ from Lattice QCD: A
    MITP/21-019 CERN-TH-2021-047 Hadronic light-by-light contribution to (g − 2)µ from lattice QCD: a complete calculation En-Hung Chao,1 Renwick J. Hudspith,1 Antoine G´erardin,2 Jeremy R. Green,3 Harvey B. Meyer,1, 4, 5 and Konstantin Ottnad1 1PRISMA+ Cluster of Excellence & Institut f¨urKernphysik, Johannes Gutenberg-Universit¨atMainz, D-55099 Mainz, Germany 2Aix Marseille Univ, Universit´ede Toulon, CNRS, CPT, Marseille, France 3Theoretical Physics Department, CERN, 1211 Geneva 23, Switzerland 4Helmholtz Institut Mainz, Staudingerweg 18, D-55128 Mainz, Germany 5GSI Helmholtzzentrum f¨urSchwerionenforschung, Darmstadt, Germany (Dated: April 7, 2021) We compute the hadronic light-by-light scattering contribution to the muon g 2 − from the up, down, and strange-quark sector directly using lattice QCD. Our calcu- lation features evaluations of all possible Wick-contractions of the relevant hadronic four-point function and incorporates several different pion masses, volumes, and lattice-spacings. We obtain a value of aHlbl = 106:8(14:7) 10−11 (adding statistical µ × and systematic errors in quadrature), which is consistent with current phenomenolog- ical estimates and a previous lattice determination. It now appears conclusive that the hadronic light-by-light contribution cannot explain the current tension between theory and experiment for the muon g 2. − I. INTRODUCTION The anomalous magnetic moment of the muon, aµ (g 2)µ=2, is one of the most precisely measured quantities of the Standard Model (SM)≡ of− particle physics. Its value is of considerable interest to the physics community as, currently, there exists a 3:7σ tension between the experimental determination of Ref.
    [Show full text]
  • Angular Distribution Measurement of Beam-Foil Muonium Part II: Muon Injection Simulation for a New Muon G-2 Experiment
    LAr-12380-T DE93 002178 Part I: Angular Distribution Measurement of Beam-Foil Muonium Part II: Muon Injection Simulation for a New Muon g-2 Experiment Hyo Eun Ahn* 'Guest Scientist at Los Alamos. Department of Physics, Yale University, New Haven, CT 06511-8167. DISTFUDUTiCN Of-' TH5S DOCUMENT 16 f7\\C^ /A\ fl^ir?Trr)/?^i(^ Los A|amos National Laboratoryy L ^© ZAiUaiLI LJ U\VJ& LoL s Alamos.NeAlN w MexicMi o 8754875455 Acknowledgement s I thank my advisor, Vernon Hughes, for his support and guidance throughout the last five years and for providing me an opportunity to work on both muonium experiments at LAMPF and the simulation study on muon g—2 experiment at BNL. I am grateful to Walter Lysenko for introducing me to the simulation study of muon injection and the availability of his help whenever I need. I also like to thank my collaborators for the angular distribution experiment. They are Frank Chmely, Ver- non Hughes, Steve Kittell, Yunan Kuang, Bjorn Matthias, Hans-Jurgen Mundinger, Benwen Ni, Gisbert zu Putlitz, Reiner Schaefer, and Kim Woodle. This experiment would not have been possible without the effort and commitment of these co-workers. Special thanks goes to Bjorn Matthias ior many helpful remarks and discussion from the first stage of data analysis to reading this manuscript. Technical support from LAMPF staff was marvelous. Thanks goes to Jov Ivie, Chandra Pillai, Richard Werbeck, and the LAMPF staff. I appreciate the help of the staff at the data analysis center (DAC) of LAMPF; they are Art Chavez, John Faucett, Elvira Martinez, and Mike Oothoudt.
    [Show full text]
  • Experimental Limits for the Electron-Proton Charge Difference and for the Neutron Charge
    790 Session P 1 (II and III) polarized muons were stopped in argon Our recent measurements of the asymmetry para­ at different magnetic fields and for case I pions were meter, a, for various gases at high pressure, done in stopped. The solid curves were obtained from the a free muon precession experiment3), give : analysis of the data and represent the per cent am­ plitude of A compared to the total counting rate. The dashed curves are theoretical line shapes centered in each case at the muonium precession frequency predicted from the measured value of the magnetic field. Resonances are clearly seen in cases II and Since depolarization in this experiment is a necessary III and indicate abundant formation of muonium condition for muonium formation, it can be conclu­ in pure argon. ded that no more than one half of the muons stopping The general conditions required to form muonium in SF6 and 02 form muonium, whereas all of the and to retain its polarization are not well understood. muons may form muonium in A, N2, and N20. From our experiments alone it is not determined In view of the abundant formation of muonium in whether the high purity of the argon gas is required, pure argon, it should be possible to measure the although if they are combined with unpublished hyperfine structure, Av, of muonium with high preci­ negative results of others2) it appears that the purity sion. Comparison of a precise experimental value is essential. If this is indeed true, it seems quite for Av with the theoretical value would provide a likely that free muonium is lost in a chemical reac­ critical test of electrodynamics involving the muon tion in impure argon.
    [Show full text]
  • RCED-85-96 DOE's Physics Accelerators
    DOE’s Physics Accelerators: Their Costs And Benefits This report provides an inventory of the Department of Energy’s existing and planned high-energy physics and nuclear physics accelerator facilities, identifies their as- sociated costs, and presents information on the benefits being derived from their construction and operation. These facilities are the primary tools used by high-energy and nuclear physicists to learn more about what energy and matter consist of and how their component parts or particles are influenced by the most basic natural forces. Of DOE’s $728 million budget for high-energy physics and nuclear physics during fiscal year 1985, about $372.1 million is earmarked for operating 14 DOE-supported accelerator facilities coast-to-coast. DOE’s investment in these facilities amounts to about $1.2 billion. If DOE’s current plans for adding new facilities are carried out, this investment could grow by about $4.3 billion through fiscal year 1994. Annual facility operating costs wilt also grow by about $230 million, or an increase of about 60 percent over current costs. The primary benefits gained from DOE’s investment in these facilities are new scientific knowledge and the education and training of future physicists. Accor- ding to DOE and accelerator facility officials, accelerator particle beams are also used in other scientific applications and have some medical and industrial applications. GAOIRCED-85-96 B APRIL 1,198s 031763 UNITED STATES GENERAL ACCOUNTING OFFICE WASHINGTON, D.C. 20548 RESOURCES, COMMUNlfY, \ND ECONOMIC DEVELOPMENT DIV ISlON B-217863 The Honorable J. Bennett Johnston Ranking Minority Member Subcommittee on Energy and Water Development Committee on Appropriations United States Senate Dear Senator Johnston: This report responds to your request dated November 25, 1984.
    [Show full text]
  • Study of Nuclear Properties with Muonic Atoms
    EPJ manuscript No. (will be inserted by the editor) Study of nuclear properties with muonic atoms A. Knecht1a, A. Skawran1;2b, and S. M. Vogiatzi1;2c 1 Paul Scherrer Institut, Villigen, Switzerland 2 Institut f¨urTeilchen- und Astrophysik, ETH Z¨urich, Switzerland Received: date / Revised version: date Abstract. Muons are a fascinating probe to study nuclear properties. Muonic atoms can easily be formed by stopping negative muons inside a material. The muon is subsequently captured by the nucleus and, due to its much higher mass compared to the electron, orbits the nucleus at very small distances. During this atomic capture process the muon emits characteristic X-rays during its cascade down to the ground state. The energies of these X-rays reveal the muonic energy level scheme, from which properties like the nuclear charge radius or its quadrupole moment can be extracted. While almost all stable elements have been examined using muons, probing highly radioactive atoms has so far not been possible. The muX experiment has developed a technique based on transfer reaction inside a high pressure hydrogen/deuterium gas cell to examine targets available only in microgram quantities. PACS. 14.60. Ef Muons { 36.10.Dr Positronium, muonium, muonic atoms and molecules { 32.30.Rj X-ray spectra { 21.10.-k General and average properties of nuclei 1 Introduction Muons are fascinating particles with experiments being conducted in the context of particle, nuclear and atomic physics [1]. Additionally, also applied research is possible by measuring the spin precession and dynamics of muons inside materials through the µSR technique [2] thus probing the internal magnetic fields of the sample under study.
    [Show full text]
  • The Nuclear Physics of Muon Capture
    Physics Reports 354 (2001) 243–409 The nuclear physics of muon capture D.F. Measday ∗ University of British Columbia, 6224 Agricultural Rd., Vancouver, BC, Canada V6T 1Z1 Received December 2000; editor: G:E: Brown Contents 4.8. Charged particles 330 4.9. Fission 335 1. Introduction 245 5. -ray studies 343 1.1. Prologue 245 5.1. Introduction 343 1.2. General introduction 245 5.2. Silicon-28 350 1.3. Previous reviews 247 5.3. Lithium, beryllium and boron 360 2. Fundamental concepts 248 5.4. Carbon, nitrogen and oxygen 363 2.1. Properties of the muon and neutrino 248 5.5. Fluorine and neon 372 2.2. Weak interactions 253 5.6. Sodium, magnesium, aluminium, 372 3. Muonic atom 264 phosphorus 3.1. Atomic capture 264 5.7. Sulphur, chlorine, and potassium 377 3.2. Muonic cascade 269 5.8. Calcium 379 3.3. Hyperÿne transition 275 5.9. Heavy elements 383 4. Muon capture in nuclei 281 6. Other topics 387 4.1. Hydrogen 282 6.1. Radiative muon capture 387 4.2. Deuterium and tritium 284 6.2. Summary of g determinations 391 4.3. Helium-3 290 P 6.3. The (; e±) reaction 393 4.4. Helium-4 294 7. Summary 395 4.5. Total capture rate 294 Acknowledgements 396 4.6. General features in nuclei 300 References 397 4.7. Neutron production 311 ∗ Tel.: +1-604-822-5098; fax: +1-604-822-5098. E-mail address: [email protected] (D.F. Measday). 0370-1573/01/$ - see front matter c 2001 Published by Elsevier Science B.V.
    [Show full text]
  • ELEMENTARY PARTICLES in PHYSICS 1 Elementary Particles in Physics S
    ELEMENTARY PARTICLES IN PHYSICS 1 Elementary Particles in Physics S. Gasiorowicz and P. Langacker Elementary-particle physics deals with the fundamental constituents of mat- ter and their interactions. In the past several decades an enormous amount of experimental information has been accumulated, and many patterns and sys- tematic features have been observed. Highly successful mathematical theories of the electromagnetic, weak, and strong interactions have been devised and tested. These theories, which are collectively known as the standard model, are almost certainly the correct description of Nature, to first approximation, down to a distance scale 1/1000th the size of the atomic nucleus. There are also spec- ulative but encouraging developments in the attempt to unify these interactions into a simple underlying framework, and even to incorporate quantum gravity in a parameter-free “theory of everything.” In this article we shall attempt to highlight the ways in which information has been organized, and to sketch the outlines of the standard model and its possible extensions. Classification of Particles The particles that have been identified in high-energy experiments fall into dis- tinct classes. There are the leptons (see Electron, Leptons, Neutrino, Muonium), 1 all of which have spin 2 . They may be charged or neutral. The charged lep- tons have electromagnetic as well as weak interactions; the neutral ones only interact weakly. There are three well-defined lepton pairs, the electron (e−) and − the electron neutrino (νe), the muon (µ ) and the muon neutrino (νµ), and the (much heavier) charged lepton, the tau (τ), and its tau neutrino (ντ ). These particles all have antiparticles, in accordance with the predictions of relativistic quantum mechanics (see CPT Theorem).
    [Show full text]
  • Positronium and Muonium Two Photon Laser Spectroscopy
    Positronium and Muonium two photon laser spectroscopy Paolo Crivelli Institute for Particle Physics and Astrophysics, ETH Zurich LEAP 2018- 16th of March 2018 – Paris (France) Leptonic atoms PrecisePrecise test test of of FundamentalFundamental boundbound state state QED QED freefree from from finite finite size size effects effects constantsconstants PositroniumPositronium (Ps) (Ps) MuoniumMuonium (Mu) (Mu) ee- - ee+ + TestTest of of the the fundamental fundamental TestTest the the effect effect of of gravity gravity symmetriessymmetries and and search search onon forfor new new physics physics anti-matteranti-matter See talks Vargas and Moskal See talk A. Soter ApplicationsApplications in in material material TODAY: arXiv:1803.05744 [hep-ex] sciencescience Ps/Mu energy levels Ps Energy levels Mu Energy levels n n 4 4 3S 3P 3D 3S 3P 3D 3 3 3 2 S 1.1 s 2P 3.2 ns 2S 2.2 s 2P 1.6 ns 2 1 2 2 photons transition: 2 photons transition: =486 nm =244 nm Natural linewidth: Natural linewidth: 1.2 MHz 144 kHz 3S 142 ns 1S 2.2 s 1 1 1 Positronium 1S-2S transition S. G. Karshenboim, Phys. Rep. 422, 1 (2005) Theory: νtheory=1233607222.2(6 ) MHz K. Pachucki and S. G. Karshenboim, Phys. Rev. A60, 2792 (1999), K. Melnikov and A. Yelkhovsky, Phys. Lett. B458, 143 (1999)¨. Adkins, Kim, Parsons and Fell, PRL 115 233401 (2015) Experiments: νa=1233607216 .4 (3.2 ) MHz M. S. Fee et al., Phys. Rev. Lett. 70, 1397 (1993) S. Chu, A. P. Mills, Jr. and J. Hall, Phys. Rev. Lett. 52,1689 (1984) New measurement ongoing at ETHZ: goal 0.5 MHz 1) Check QED calculations (7m) 2) Stringent test of SME See talk A.Vargas 3) Positron to electron mass ratio Paolo Crivelli Muonium 1S-2S spectroscopy Experiment: Meyer et al.
    [Show full text]
  • Muonium-Antimuonium Oscillations in Effective Field Theory
    PHYSICAL REVIEW D 102, 095001 (2020) Muonium-antimuonium oscillations in effective field theory Renae Conlin 1 and Alexey A. Petrov 1,2 1Department of Physics and Astronomy Wayne State University, Detroit, Michigan 48201, USA 2Leinweber Center for Theoretical Physics University of Michigan, Ann Arbor, Michigan 48196, USA (Received 3 June 2020; accepted 9 October 2020; published 3 November 2020) Flavor violating processes in the lepton sector have highly suppressed branching ratios in the standard model, mainly due to the tiny neutrino mass. This means that observing a lepton flavor violation (LFV) in the next round of experiments would constitute a clear indication of physics beyond the standard model (BSM). We revisit a discussion of one possible way to search for LFV, muonium-antimuonium oscillations. This process violates the muon lepton number by two units and could be sensitive to the types of BSM physics that are not probed by other types of LFV processes. Using techniques of effective field theory, we calculate the mass and width differences of the mass eigenstates of muonium. We argue that its invisible decays give the parametrically leading contribution to the lifetime difference and put constraints on the scales of new physics probed by effective operators in muonium oscillations. DOI: 10.1103/PhysRevD.102.095001 I. INTRODUCTION So far, we have not yet observed FCNC in the charged Flavor-changing neutral current (FCNC) interactions lepton sector. This is because in the standard model with serve as a powerful probe of physics beyond the standard massive neutrinos, the charged lepton flavor violating (CLFV) transitions are suppressed by the powers of model (BSM).
    [Show full text]
  • Arxiv:1311.3245V3 [Hep-Ph] 12 Nov 2014 Cay Products Include Not Only Monochromatic Photons, Light-Front Techniques
    True Muonium (µ+µ−) on the Light Front Henry Lamm∗ and Richard F. Lebedy Department of Physics, Arizona State University, Tempe, AZ 85287 (Dated: April, 2014) Applying Discretized Light Cone Quantization, we perform the first calculation of the spectrum of true muonium, the µ+µ− atom, as modified by the inclusion of an jee¯i Fock component. The shift in the mass eigenvalue is found to be largest for triplet states. If me is taken to be a substantial 3 fraction of mµ, the integrated probability of the electronic component of the 1 S1 state is found to be as large as O(10−2). Initial studies of the Lamb shift for the atom are performed. Directions for making the simulations fully realistic are discussed. PACS numbers: 36.10.Ee, 11.10.Ef, 11.10.St, 12.20.Ds I. INTRODUCTION of the atoms. Indeed, remarkable experiments can in principle be performed on these \atoms in flight", includ- The atom consisting of a µ+µ− bound state, called true ing measurements of the Lamb shift [7]. Bound states in muonium [in distinction from conventional muonium, the quantum field theory (QFT) are notoriously complicated atom (µ+e−)] has not yet been identified, despite much objects, due not only to the fact that the vacuum con- more exotic bound states having been successfully char- sists of an arbitrarily large number of virtual particles, acterized, such as πµ atoms [1] and even the dipositro- but also because the constituents can be relativistic, and nium (e+e−)(e+e−) molecule [2]. While (µ+µ−) atoms the required boosts to relate the components of the wave have doubtless been produced many times, for example function depend in a detailed way upon the interaction.
    [Show full text]