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The Particle Zoo
219 8 The Particle Zoo 8.1 Introduction Around 1960 the situation in particle physics was very confusing. Elementary particlesa such as the photon, electron, muon and neutrino were known, but in addition many more particles were being discovered and almost any experiment added more to the list. The main property that these new particles had in common was that they were strongly interacting, meaning that they would interact strongly with protons and neutrons. In this they were different from photons, electrons, muons and neutrinos. A muon may actually traverse a nucleus without disturbing it, and a neutrino, being electrically neutral, may go through huge amounts of matter without any interaction. In other words, in some vague way these new particles seemed to belong to the same group of by Dr. Horst Wahl on 08/28/12. For personal use only. particles as the proton and neutron. In those days proton and neutron were mysterious as well, they seemed to be complicated compound states. At some point a classification scheme for all these particles including proton and neutron was introduced, and once that was done the situation clarified considerably. In that Facts And Mysteries In Elementary Particle Physics Downloaded from www.worldscientific.com era theoretical particle physics was dominated by Gell-Mann, who contributed enormously to that process of systematization and clarification. The result of this massive amount of experimental and theoretical work was the introduction of quarks, and the understanding that all those ‘new’ particles as well as the proton aWe call a particle elementary if we do not know of a further substructure. -
CERN Courier–Digital Edition
CERNMarch/April 2021 cerncourier.com COURIERReporting on international high-energy physics WELCOME CERN Courier – digital edition Welcome to the digital edition of the March/April 2021 issue of CERN Courier. Hadron colliders have contributed to a golden era of discovery in high-energy physics, hosting experiments that have enabled physicists to unearth the cornerstones of the Standard Model. This success story began 50 years ago with CERN’s Intersecting Storage Rings (featured on the cover of this issue) and culminated in the Large Hadron Collider (p38) – which has spawned thousands of papers in its first 10 years of operations alone (p47). It also bodes well for a potential future circular collider at CERN operating at a centre-of-mass energy of at least 100 TeV, a feasibility study for which is now in full swing. Even hadron colliders have their limits, however. To explore possible new physics at the highest energy scales, physicists are mounting a series of experiments to search for very weakly interacting “slim” particles that arise from extensions in the Standard Model (p25). Also celebrating a golden anniversary this year is the Institute for Nuclear Research in Moscow (p33), while, elsewhere in this issue: quantum sensors HADRON COLLIDERS target gravitational waves (p10); X-rays go behind the scenes of supernova 50 years of discovery 1987A (p12); a high-performance computing collaboration forms to handle the big-physics data onslaught (p22); Steven Weinberg talks about his latest work (p51); and much more. To sign up to the new-issue alert, please visit: http://comms.iop.org/k/iop/cerncourier To subscribe to the magazine, please visit: https://cerncourier.com/p/about-cern-courier EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING ATLAS spots rare Higgs decay Weinberg on effective field theory Hunting for WISPs CCMarApr21_Cover_v1.indd 1 12/02/2021 09:24 CERNCOURIER www. -
Planck Mass Rotons As Cold Dark Matter and Quintessence* F
Planck Mass Rotons as Cold Dark Matter and Quintessence* F. Winterberg Department of Physics, University of Nevada, Reno, USA Reprint requests to Prof. F. W.; Fax: (775) 784-1398 Z. Naturforsch. 57a, 202–204 (2002); received January 3, 2002 According to the Planck aether hypothesis, the vacuum of space is a superfluid made up of Planck mass particles, with the particles of the standard model explained as quasiparticle – excitations of this superfluid. Astrophysical data suggests that ≈70% of the vacuum energy, called quintessence, is a neg- ative pressure medium, with ≈26% cold dark matter and the remaining ≈4% baryonic matter and radi- ation. This division in parts is about the same as for rotons in superfluid helium, in terms of the Debye energy with a ≈70% energy gap and ≈25% kinetic energy. Having the structure of small vortices, the rotons act like a caviton fluid with a negative pressure. Replacing the Debye energy with the Planck en- ergy, it is conjectured that cold dark matter and quintessence are Planck mass rotons with an energy be- low the Planck energy. Key words: Analog Models of General Relativity. 1. Introduction The analogies between Yang Mills theories and vor- tex dynamics [3], and the analogies between general With greatly improved observational techniques a relativity and condensed matter physics [4 –10] sug- number of important facts about the physical content gest that string theory should perhaps be replaced by and large scale structure of our universe have emerged. some kind of vortex dynamics at the Planck scale. The They are: successful replacement of the bosonic string theory in 1. -
CERN Celebrates Discoveries
INTERNATIONAL JOURNAL OF HIGH-ENERGY PHYSICS CERN COURIER VOLUME 43 NUMBER 10 DECEMBER 2003 CERN celebrates discoveries NEW PARTICLES NETWORKS SPAIN Protons make pentaquarks p5 Measuring the digital divide pl7 Particle physics thrives p30 16 KPH impact 113 KPH impact series VISyN High Voltage Power Supplies When the objective is to measure the almost immeasurable, the VISyN-Series is the detector power supply of choice. These multi-output, card based high voltage power supplies are stable, predictable, and versatile. VISyN is now manufactured by Universal High Voltage, a world leader in high voltage power supplies, whose products are in use in every national laboratory. For worldwide sales and service, contact the VISyN product group at Universal High Voltage. Universal High Voltage Your High Voltage Power Partner 57 Commerce Drive, Brookfield CT 06804 USA « (203) 740-8555 • Fax (203) 740-9555 www.universalhv.com Covering current developments in high- energy physics and related fields worldwide CERN Courier (ISSN 0304-288X) is distributed to member state governments, institutes and laboratories affiliated with CERN, and to their personnel. It is published monthly, except for January and August, in English and French editions. The views expressed are CERN not necessarily those of the CERN management. Editor Christine Sutton CERN, 1211 Geneva 23, Switzerland E-mail: [email protected] Fax:+41 (22) 782 1906 Web: cerncourier.com COURIER Advisory Board R Landua (Chairman), P Sphicas, K Potter, E Lillest0l, C Detraz, H Hoffmann, R Bailey -
Absence of Landau Damping in Driven Three-Component Bose–Einstein
www.nature.com/scientificreports OPEN Absence of Landau damping in driven three-component Bose– Einstein condensate in optical Received: 19 June 2017 Accepted: 10 July 2018 lattices Published: xx xx xxxx Gavriil Shchedrin, Daniel Jaschke & Lincoln D. Carr We explore the quantum many-body physics of a three-component Bose-Einstein condensate in an optical lattice driven by laser felds in V and Λ confgurations. We obtain exact analytical expressions for the energy spectrum and amplitudes of elementary excitations, and discover symmetries among them. We demonstrate that the applied laser felds induce a gap in the otherwise gapless Bogoliubov spectrum. We fnd that Landau damping of the collective modes above the energy of the gap is carried by laser-induced roton modes and is considerably suppressed compared to the phonon-mediated damping endemic to undriven scalar condensates Multicomponent Bose-Einstein condensates (BECs) are a unique form of matter that allow one to explore coherent many-body phenomena in a macroscopic quantum system by manipulating its internal degrees of freedom1–3. Te ground state of alkali-based BECs, which includes 7Li, 23Na, and 87Rb, is characterized by the hyperfne spin F, that can be best probed in optical lattices, which liberate its 2F + 1 internal components and thus provides a direct access to its internal structure4–11. Driven three-component F = 1 BECs in V and Λ confgurations (see Fig. 1(b) and (c)) are totally distinct from two-component BECs3 due to the light interaction with three-level systems that results in the laser-induced coherence between excited states and ultimately leads to a number of fascinating physical phenomena, such as lasing without inversion (LWI)12,13, ultraslow light14,15, and quantum memory16. -
Physical Vacuum Is a Special Superfluid Medium
Physical vacuum is a special superfluid medium Valeriy I. Sbitnev∗ St. Petersburg B. P. Konstantinov Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, Leningrad district, 188350, Russia; Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA (Dated: August 9, 2016) The Navier-Stokes equation contains two terms which have been subjected to slight modification: (a) the viscosity term depends of time (the viscosity in average on time is zero, but its variance is non-zero); (b) the pressure gradient contains an added term describing the quantum entropy gradient multiplied by the pressure. Owing to these modifications, the Navier-Stokes equation can be reduced to the Schr¨odingerequation describing behavior of a particle into the vacuum being as a superfluid medium. Vortex structures arising in this medium show infinitely long life owing to zeroth average viscosity. The non-zero variance describes exchange of the vortex energy with zero-point energy of the vacuum. Radius of the vortex trembles around some average value. This observation sheds the light to the Zitterbewegung phenomenon. The long-lived vortex has a non-zero core where the vortex velocity vanishes. Keywords: Navier-Stokes; Schr¨odinger; zero-point fluctuations; superfluid vacuum; vortex; Bohmian trajectory; interference I. INTRODUCTION registered. Instead, the wave function represents it existence within an experimental scene [13]. A dramatic situation in physical understand- Another interpretation was proposed by Louis ing of the nature emerged in the late of 19th cen- de Broglie [18], which permits to explain such an tury. Observed phenomena on micro scales came experiment. In de Broglie's wave mechanics and into contradiction with the general positions of the double solution theory there are two waves. -
A Time of Great Growth
Newsletter | Spring 2019 A Time of Great Growth Heartfelt greetings from the UC Riverside Department of Physics and Astronomy. This is our annual newsletter, sent out each Spring to stay connected with our former students, retired faculty, and friends in the wider community. The Department continues to grow, not merely in size but also in stature and reputation. For the 2018-2019 academic year, we were pleased to welcome two new faculty: Professors Thomas Kuhlman and Barry Barish. Professor Kuhlman was previously on the faculty at the University of Illinois at Urbana-Champaign. He joins our efforts in the emerging field of biophysics. His research lies in the quantitative imaging and theoretical modeling of biological systems. He works on genome dynamics, quantification of the activity of transposable elements in living cells, and applications to the engineering of genome editing. Professor Barry Barish, who joins us from Caltech, is the winner of the 2017 Nobel Prize in Physics. He brings great prestige to our Department. Along with Professor Richard Schrock of the Department of Chemistry, who also joined UCR in 2018, UCR now has two Nobel Prize winners on its faculty. Professor Barish is an expert on the detection and physics of gravitational waves. He has been one of the key figures in the conception, construction, and operation of the LIGO detector, where gravitational waves were first discovered in 2015, and which led to his Nobel Prize. He is a member of the National Academy of Sciences and the winner of many other prestigious awards. The discovery of gravitational waves is one of the most exciting developments in physics so far this century. -
Exploring the Stability and Dynamics of Dipolar Matter-Wave Dark Solitons
PHYSICAL REVIEW A 93, 063617 (2016) Exploring the stability and dynamics of dipolar matter-wave dark solitons M. J. Edmonds,1 T. Bland,1 D. H. J. O’Dell,2 and N. G. Parker1 1Joint Quantum Centre Durham–Newcastle, School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom 2Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1, Canada (Received 4 March 2016; published 15 June 2016) We study the stability, form, and interaction of single and multiple dark solitons in quasi-one-dimensional dipolar Bose-Einstein condensates. The solitons are found numerically as stationary solutions in the moving frame of a nonlocal Gross Pitaevskii equation and characterized as a function of the key experimental parameters, namely the ratio of the dipolar atomic interactions to the van der Waals interactions, the polarization angle, and the condensate width. The solutions and their integrals of motion are strongly affected by the phonon and roton instabilities of the system. Dipolar matter-wave dark solitons propagate without dispersion and collide elastically away from these instabilities, with the dipolar interactions contributing an additional repulsion or attraction to the soliton-soliton interaction. However, close to the instabilities, the collisions are weakly dissipative. DOI: 10.1103/PhysRevA.93.063617 I. INTRODUCTION the atoms and their interactions using lasers as well as magnetic and electric fields. This, for example, has led to proposals to Solitary waves, or solitons, are excitations of nonlinear access exotic solitons such as in spin-orbit coupled conden- systems that possess both wavelike and particle-like qual- sates [21–23], chiral solitons in “interacting” gauge theories ities. -
Ilia Engineer 1971 16Th Anniversary Issue
Vol 17 No 1 Jun Jul _Ilia Engineer 1971 16th Anniversary Issue www.americanradiohistory.com RCA Engineer Staff W. O. Hadlock Editor J. C. Phillips Associate Editor Relax, John Q. Let's talk this over Miss Diane Juchno Editorial Secretary Joan P. Dunn Design and Layout rsary issu priate to Mrs. Julianne Clifton pay tribute to you, the reader -contributor. Supported by your Editorial Representative Subscriptions and the Technical Publications editorial staff, you have made this publication uniq Consulting Editors in its class. Outstanding both in the variety and the quality of its content, the RC Engineer is a major forum for communication among members of the RCA profes- C. A. Meyer Technical Publications Adm., sional community. Electronic Components C. W. Sall Technical Publications Adm., It is appropriate too, in these perplexing times, to give thought to another area of Laboratories communication; one which the RCA Engineer as an internal publication does not ,Strobl Technical Publications Adm. address directly. I refer to the need for each of us in the technical community to Corporate Engineering Services help put the layman at ease with technology so he can make informed decisions about its use. Editorial Advisory Board In recent months this need has been starkly and, in a way, brutally highlighted. The P. A. Beeby VP, Technical Operations. spectacular successes of the space program, which displayed unprecedented tech Systems Development Division, Computer Systems cal virtuosity, drew responses from the public ranging from disbelief to near adulation. Almost simultaneously, engineers and scientists were shocked to find themselves J. J. Brant Staff VP, Industrial Relations-International and their disciplines held responsible for the great social concerns of our time. -
The AWAKE Acceleration Scheme for New Particle Physics Experiments at CERN
AWAKE++: the AWAKE Acceleration Scheme for New Particle Physics Experiments at CERN W. Bartmann1, A. Caldwell2, M. Calviani1, J. Chappell3, P. Crivelli4, H. Damerau1, E. Depero4, S. Doebert1, J. Gall1, S. Gninenko5, B. Goddard1, D. Grenier1, E. Gschwendtner*1, Ch. Hessler1, A. Hartin3, F. Keeble3, J. Osborne1, A. Pardons1, A. Petrenko1, A. Scaachi3, and M. Wing3 1CERN, Geneva, Switzerland 2Max Planck Institute for Physics, Munich, Germany 3University College London, London, UK 4ETH Zürich, Switzerland 5INR Moscow, Russia 1 Abstract The AWAKE experiment reached all planned milestones during Run 1 (2016-18), notably the demon- stration of strong plasma wakes generated by proton beams and the acceleration of externally injected electrons to multi-GeV energy levels in the proton driven plasma wakefields. During Run 2 (2021 - 2024) AWAKE aims to demonstrate the scalability and the acceleration of elec- trons to high energies while maintaining the beam quality. Within the Physics Beyond Colliders (PBC) study AWAKE++ has explored the feasibility of the AWAKE acceleration scheme for new particle physics experiments at CERN. Assuming continued success of the AWAKE program, AWAKE will be in the position to use the AWAKE scheme for particle physics ap- plications such as fixed target experiments for dark photon searches and also for future electron-proton or electron-ion colliders. With strong support from the accelerator and high energy physics community, these experiments could be installed during CERN LS3; the integration and beam line design show the feasibility of a fixed target experiment in the AWAKE facility, downstream of the AWAKE experiment in the former CNGS area. The expected electrons on target for fixed target experiments exceeds the electrons on target by three to four orders of magnitude with respect to the current NA64 experiment, making it a very promising experiment in the search for new physics. -
Barry Barish and the Gde: Mission Achievable
INTERVIEW Barry Barish and the GDE: mission achievable The head of the Global Design Effort for a future International Linear Collider talks about challenges past, present and future. Barry Barish likes a challenge. He admits to a complete tendency to go for the difficult in his research – in his view, life is an adventure. Some might say that his most recent challenge would fit well with a certain famous TV series: “Your mission, should you choose to accept it… is to produce a design for the International Linear Collider that includes a detailed design concept, performance assessments, reliable international costing, an industrialization plan, and siting analysis, as well as detector concepts and scope.” Barish did indeed accept the challenge in March 2005, when he became director of the Global Design Effort (GDE) for a proposed International Linear Collider (ILC). He started in a directorate of one – himself – at the head of a “virtual” laboratory of hundreds of physicists and engineers around the globe. To run the “lab” he has set up a small executive committee, which includes three regional directors (for the Americas, Asia and Europe), three project manag- ers and two leading accelerator experts. There are also boards for R&D, change control and design cost. Barish operates from his base at Caltech, where he has been since 1962 and ultimately became Linde Professor of Physics (now emeri- tus). His taste for research challenges became evident in the 1970s, when he was co-spokesperson with Frank Sciulli (also at Caltech) of the “narrow band” neutrino experiment at Fermilab that studied Barish became director of the Global Design Effort for the International weak neutral currents and the quark substructure of the nucleon. -
Vibrational Substructure in the OH Stretching Transition of Water and HOD
9054 J. Phys. Chem. A 2004, 108, 9054-9063 Vibrational Substructure in the OH Stretching Transition of Water and HOD Zhaohui Wang, Andrei Pakoulev, Yoonsoo Pang, and Dana D. Dlott* School of Chemical Sciences, UniVersity of Illinois at Urbana-Champaign, 600 South Mathews AVenue, Urbana, Illinois 61801 ReceiVed: April 2, 2004; In Final Form: August 13, 2004 Ultrafast nonlinear vibrational spectroscopy with mid-IR pumping and incoherent anti-Stokes Raman probing is used to study V)1 excitations of OH stretching (νOH) of water and of HOD in D2O solvent (HOD/D2O). The parent νOH decay and the appearance of daughter stretching and bending excitations are simultaneously monitored, which allows for characterization of the stretch decay pathways. At all times and with all pump frequencies within the νOH band, the excited-state spectrum can be fit by two overlapping subbands, a broader R B red-shifted band νOH and a narrower blue-shifted band νOH. We show these subbands are dynamically distinguishable. They decay with different lifetimes and evidence characteristically different decay pathways. R B ∼ Excitations of the νOH subband generate bending vibrations that νOH does not. The shorter lifetime ( 0.5 ps) R B - of the νOH subband compared to the νOH subband (0.8 0.9 ps) results primarily from enhanced stretch-to- bend anharmonic coupling. The subbands represent persistent structures in the excited state, in that interconversion between subbands (2-10 ps) is slower than excited-state decay. A tentative structural R interpretation is proposed. The νOH subband, on the basis of simulations, its red shift ,and its shorter lifetime, R is proposed to result from strongly hydrogen-bonded “ice-like” water.