DOCSLIB.ORG

Where the Complications Start

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Where the Complications Start 4 P. Grang´eet al.: The fine-tuning problem revisited in the light of the Taylor-Lagrange renormalization scheme the necessary (ultra-soft) cut-o in the calculation of the integral. After an evident change of variable, we get 3M 4 X M 2 ⇥ = H dX f H X (16) 1b,H 32⌅2v2 X +1 Λ2 ↵0 ⌃ ⌥ 3M 4 1 M 2 = H dX 1 f H X . 32⌅2v2 − X +1 Λ2 ↵0 ⌃ ⌥ ⌃ ⌥ The first term under the integral can be reduced to a pseudo-function, using (11). Indeed, with Z =1/X,we have dZ M 2 1 dXf(X)= f H (17) Z2 Λ2 Z ↵0 ↵0 ⌃ ⌥ 1 = dZ Pf Z2 ↵0 ⌃ ⌥ 1 = =0. −Z ⇧ where the complications start ⇧ a ⇧ one explicit mass scale of the Standard Model is a mass-squared parameter The notation f(u) simply indicates⇧ that f(u) should be taken at the value |u = a, the lower limit of integration be- defining the leading orderFig. shape 1. Radiativeof the Mexican corrections Hat to the Higgs mass in the Stan- dard Model in second order of perturbation theory. For simplic- ing taken care of by the definition of the pseudo-function. V()ϕ D 2 n mass. The “cancellation” of massless bosons to give ity, we have not shown contributions from ghosts or Goldstone This result is reminiscent of the property d p(p ) = 0, a massive boson, as anticipated by Anderson and • to get the correct shape for electroweak developed in the 1964 papers, is the famous Higgs for any n, in DR [15]. mechanism; for their contributions to its discovery, bosons. 2 Englert and Higgs received this year’s Nobel Prize symmetry breaking, m0 < 0 (tachyonic) ⌦ in Physics. (For more, see page 10 of this issue.) The self-energy thus writes As recounted in his 2010 talk “My Life as a 1 Boson,” Higgs submitted his second paper of 1964 2 2 4 to Physics Letters, which promptly rejected it.10 ! V0 = m0 H + λ H 4 2 Shocked at that setback, he revised and expanded shown in Fig. 1. We have| | left out,2 | for| simplicity, all contri- 3MH 1 MH the manuscript, adding the key observation that ⇥1b,H = dX f X . (18) when applied to a charged spinless boson, the Higgs butions coming from ghosts and Goldstone bosons. Each 2 2 2 mechanism leaves behind a neutral spinless boson. −32⌅ v 0 X +1 Λ That neutral particle—the Higgs boson—has a mass • assume electroweak symmetry ↵ ⌃ ⌥ determined by the shape of the Mexican-hat poten- Re ϕ diagram in this figure gives a contribution to the self- tial energy density, but that mass cannot be expressed 2 2 2 in terms of the mass generated for the gauge boson. 4 P. Grang´eetIm ϕ al.: The fine-tuning problem revisited in the light of the Taylor-Lagrangebreaking, renormalization scheme and start computing quantum Higgs sent the improved revision to a different jour- energy i⇥(p ), where p is the four-momentum of the The constant factor MH /Λ in the argument of the test nal, Physical Review Letters, and it was promptly Figure 2. The Mexican-hat potential energy density considered by the necessary (ultra-soft)− cut-o in the calculation of the accepted. Jeffrey Goldstone in his seminal 1961 paper.2 The energy density is a external particle,corrections and we involving have the Higgs boson function has no physical meaning since it can be absorbed At first, theorists thought that the most suitable integral. function of the real (Re) and imaginary (Im) values of a spinless field ϕ. After an evident change of variable, we get 2 application of spontaneous symmetry breaking to In the context of the electroweak theory developed later in the decade, by a rescaling of the arbitrary dimensionless scale ⇤ .This particle physics was in the arena of the strong inter- the yellow ball at the top of the hat would represent the symmetric 4 2 2 2 2 actions. Only in 1967 did Weinberg, and, independ- 3MH X MH solution for the potential, in which the photon, W bosons, and Z boson ⇥1b,H = dX f X (16) ently, Salam, realize that the Higgs mechanism of- •2 2 The leadingM2 = orderM + corrections⇥(M ) . involve (13) are all massless. The blue ball in the trough represents the solution after 32⌅ v 0 X +1 Λ H 0 H can be easily seen by applying the Lagrange formula (6) fered an elegant explanation of the weak interactions. ↵ ⌃ ⌥ symmetry breaking. In that solution the W and Z bosons are massive 3M 4 1 M 2 2 2 In their model, which is now the electroweak portion = H dX 1 f H X . and the photon remains massless. The steepness of the trough is related 2 2 2 with the intrinsic scale a = M /Λ and k = 0. It can thus of the standard model, four Higgs fields are related 32⌅ v 0quadratically-divergent− X +1 Λ integrals over H to the mass of the Higgs boson. ↵ ⌃ ⌥ ⌃ ⌥ by a gauge symmetry of the type introduced by 1 Yang and Mills. Three Goldstone bosons are eaten The first term under the integral can be reduced to a safely be removed . to give large masses to the W+, W−, and Z bosons that decay process into two virtual Z bosons, each of pseudo-function,Using using avirtual (11).na¨ıve Indeed, momenta. cut-o with Z =1/Xto,we regularize Keep going the amplitudes, by cutting these mediate the weak interactions. An added bonus, not which, in turn, decays into an electron–positron or have We can now apply the Lagrange formula for k = 0. foreseen by Higgs and the rest, is that the Higgs muon–antimuon pair. The other shows the Higgs dZ M 2 1 field also gives mass to quarks and leptons, the ele- decay into two photons. The image on pages 28 and radiativedXf( correctionsXoff)= thef integralsH lead(17) to in thethe well UV with known some mass correc- Z2 Λ2 Z Using the boundary condition on the support of the test mentary fermions that make up matter. 29 shows a visualization of the data produced by a ↵0 ↵0 ⌃ ⌥ The mass of the Higgs boson left behind is not Higgs boson candidate at the LHC; the four decay 1 tion = dZ Pf predicted, but the interactions of the Higgs with products are muons or antimuons—a pair of each— arbitraryZ 2 ΛC cut-off scale function other elementary particles can be precisely com- whose tracks are depicted as red lines. ↵0 ⌃ ⌥ puted as a function of its mass and the masses of the The experimental results so far suggest that the 1 2 = =0. other particles. Furthermore, the exchange of virtual particle observed at the LHC is indeed a Higgs −Z 2 Xt H(X)=⇤ Xgα(X) , (19) ⇧ 3Λ Higgs bosons generates an attractive short-range boson, though not necessarily possessing exactly 2 2 ⇧ C 2 2 2 2 ⇥ force. If the Higgs boson is an elementary particle, the properties postulated by the standard model. a ⇧ TheM notation=f(uM) simply+ indicates⇧ that f(u) shouldM be +2M + M 4m + ... , as so far appears to be the case, then that force is The discovery itself is based on large excesses of H | 0 2 2 H W Z t Fig. 1. Radiative corrections to the Higgs mass in the Stan- taken at the value u = a, the lower limit of integration be- we finally get, in the limit f 1 every bit as fundamental as the gauge-boson-medi- Higgs-like events in the two decay channels de- 8⌅ v − dard Model in second order of perturbation theory. For simplic- ing taken care of by the definition of the pseudo-function. ated forces of the standard model. In that case, the scribed above, supported by less conclusive but D 2 n ⇤ ity, we have not shown contributions from ghosts or Goldstone This result is reminiscent of the property d p(p ) = 0, (14) Higgs would be the first fundamental force media- compatiblein absence excesses observed of insomething other channels. (a symmetry,for any n, in DR or [15]. other conspiracy),⇤ the electroweak scale can⌅ tor ever detected that is not a gauge boson. Figurebosons. 4 displays CMS data for the four-lepton The self-energy thus writes ⌦ 4 ⇥ channel. The measured mass is about 126 GeV/c2, where mt,MW,Z and MH are the2 masses of the top quark, 3M X dt The discovery intermediate between the mass of the Z boson and H onlyshown inbe Fig. obtained 1. We have left out, by for simplicity, fine-tuning all contri- a bare3M parameter4 1 Magainst2 (cut-off) dependent radiative The ATLAS and CMS (Compact Muon Solenoid) ex- the mass of the top quark. ⇥ = H dX f H X . (18) ⇥1b = dX∂X butions coming from ghosts and Goldstone bosons. Each W,1 Zb,H and−32⌅2v2 HiggsX +1 bosonsΛ2 respectively, and v is the vacuum 2 2 periments at the LHC were built to probe the mech- The new particle cannot be a spin-1 particle be- ↵0 ⌃ ⌥ −32⌅ v X +1 t anisms of electroweak symmetry breaking and the causecorrections thediagram decay of in such this an figure object (or gives into the two a photons contribution so -iscalled to the self-naturalness mess) rc 0 1 2 2 2 particle origins of dark matter. Wired up with about energy i⇥(p ), where p is the four-momentum of the The constant factor M /Λ in the argument of the test ↵ ⌃ ⌥ ↵ forbidden by a− general result known as the Landau– expectationH value of the Higgs potential in the Standard a hundred million readout channels each and made Yang externaltheorem.
Load more

Recommended publications
  • Gammev: Fermilab Axion-Like Particle Photon Regeneration Results
    GammeV: Fermilab Axion-like Particle Photon Regeneration Results William Wester Fermilab, MS222, Batavia IL, USA presented on behalf of the GammeV Collaboration DOI: http://dx.doi.org/10.3204/DESY-PROC-2008-02/wester william GammeV is an axion-like particle photon regeneration experiment conducted at Fermilab that employs the light shining through a wall technique. We obtain limits on the cou- pling of a photon to an axion-like particle that extend previous limits for both scalar and pseudoscalar axion-like particles in the milli-eV mass range. We are able to exclude the axion-like particle interpretation of the anomalous PVLAS 2006 result by more than 5 standard deviations. 1 Introduction The question, What are the particles that make up the dark matter of the universe?, is one of the most fundamental scientific questions today. Besides weakly interacting massive particles (WIMPs) such as neutralinos, axion-like particles or other weakly interacting sub-eV particles (WISPs) are highly motivated dark matter particle candidates since they have properties that might explain the cosmic abundance of dark matter. The milli-eV mass scale is of particular interest in modern particle physics since that mass scale may be constructed with a see-saw between the Planck and TeV mass scales, and may be related to neutrino mass differences, the dark energy density expressed in (milli-eV)4, and known dark matter candidates such as gravitinos and axion-like particles. In 2006, the PVLAS experiment reported [1] anomalous polarization effects in the presence of a magnetic field including polarization rotation and el- lipticity generation that could be interpreted as being mediated by an axion-like particle in the milli-eV mass range with a unexpectedly strong coupling to photons.
    [Show full text]
  • Circular and Linear Magnetic Birefringences in Xenon at =1064 Nm
    Downloaded from orbit.dtu.dk on: Oct 06, 2021 Circular and linear magnetic birefringences in xenon at =1064 nm Cadene, Agathe; Fouche, Mathilde; Rivere, Alice; Battesti, Remy; Coriani, Sonia; Rizzo, Antonio; Rizzo, Carlo Published in: Journal of Chemical Physics Link to article, DOI: 10.1063/1.4916049 Publication date: 2015 Document Version Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Cadene, A., Fouche, M., Rivere, A., Battesti, R., Coriani, S., Rizzo, A., & Rizzo, C. (2015). Circular and linear magnetic birefringences in xenon at =1064 nm. Journal of Chemical Physics, 142(12), [124313]. https://doi.org/10.1063/1.4916049 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Circular and linear magnetic birefringences in xenon at λ = 1064 nm Agathe Cadène, Mathilde Fouché, Alice Rivère,
    [Show full text]
  • Dark Matter and the Early Universe: a Review Arxiv:2104.11488V1 [Hep-Ph
    Dark matter and the early Universe: a review A. Arbey and F. Mahmoudi Univ Lyon, Univ Claude Bernard Lyon 1, CNRS/IN2P3, Institut de Physique des 2 Infinis de Lyon, UMR 5822, 69622 Villeurbanne, France Theoretical Physics Department, CERN, CH-1211 Geneva 23, Switzerland Institut Universitaire de France, 103 boulevard Saint-Michel, 75005 Paris, France Abstract Dark matter represents currently an outstanding problem in both cosmology and particle physics. In this review we discuss the possible explanations for dark matter and the experimental observables which can eventually lead to the discovery of dark matter and its nature, and demonstrate the close interplay between the cosmological properties of the early Universe and the observables used to constrain dark matter models in the context of new physics beyond the Standard Model. arXiv:2104.11488v1 [hep-ph] 23 Apr 2021 1 Contents 1 Introduction 3 2 Standard Cosmological Model 3 2.1 Friedmann-Lema^ıtre-Robertson-Walker model . 4 2.2 A quick story of the Universe . 5 2.3 Big-Bang nucleosynthesis . 8 3 Dark matter(s) 9 3.1 Observational evidences . 9 3.1.1 Galaxies . 9 3.1.2 Galaxy clusters . 10 3.1.3 Large and cosmological scales . 12 3.2 Generic types of dark matter . 14 4 Beyond the standard cosmological model 16 4.1 Dark energy . 17 4.2 Inflation and reheating . 19 4.3 Other models . 20 4.4 Phase transitions . 21 5 Dark matter in particle physics 21 5.1 Dark matter and new physics . 22 5.1.1 Thermal relics . 22 5.1.2 Non-thermal relics .
    [Show full text]
  • Strategies for the Detection of Dark Matter
    Bernard Sadoulet Dept. of Physics /LBNL UC Berkeley UC Institute for Nuclear and Particle Astrophysics and Cosmology (INPAC) Strategies for the Detection of Dark Matter What do we know? What have we achieved so far? Strategies for the future Strategies for the Detection f Dark Matter Hanoi 10 Aug 06 1 B.Sadoulet 1. What do we know? 2. What has been achieved? 3. Strategies for the future Standard Model of Cosmology A surprising but consistent picture Non Baryonic Λ Dark Matter Ω Ωmatter Not ordinary matter (Baryons) Nucleosynthesis Ω >> Ω = 0.047 ± 0.006 from m b WMAP Mostly cold: Not light neutrinos≠ small scale structure mv < .17eV Large Scale structure+baryon oscillation + Lyman α Strategies for the Detection f Dark Matter Hanoi 10 Aug 06 2 B.Sadoulet 1. What do we know? 2. What has been achieved? 3. Strategies for the future Ongoing Systematic Mapping dark matter and energy non baryonic Λ Quintessence baryonic clumped H2? ? gas Primordial Black Holes VMO Mirror branes ? exotic particles dust Energy in bulk MACHOs thermal non-thermal SuperWIMPs Light Neutrinos WIMPs Axions Wimpzillas Most baryonic forms excluded (independently of BBN, CMB) Particles: well defined if thermal (difficult when athermal) Additional dimensions? Strategies for the Detection f Dark Matter Hanoi 10 Aug 06 3 B.Sadoulet 1. What do we know? 2. What has been achieved? 3. Strategies for the future Standard Model of Particle Physics Fantastic success but Model is unstable Why is W and Z at ≈100 Mp? Need for new physics at that scale supersymmetry additional dimensions Flat: Cheng et al.
    [Show full text]
  • From Space, a New View of Doomsday
    Past 30 Days Welcome, kamion This page is print-ready, and this article will remain available for 90 days. Instructions for Saving | About this Service | Purchase History February 17, 2004, Tuesday SCIENCE DESK From Space, A New View Of Doomsday By DENNIS OVERBYE (NYT) 2646 words Once upon a time, if you wanted to talk about the end of the universe you had a choice, as Robert Frost put it, between fire and ice. Either the universe would collapse under its own weight one day, in a fiery ''big crunch,'' or the galaxies, now flying outward from each other, would go on coasting outward forever, forever slowing, but never stopping while the cosmos grew darker and darker, colder and colder, as the stars gradually burned out like tired bulbs. Now there is the Big Rip. Recent astronomical measurements, scientists say, cannot rule out the possibility that in a few billion years a mysterious force permeating space-time will be strong enough to blow everything apart, shred rocks, animals, molecules and finally even atoms in a last seemingly mad instant of cosmic self-abnegation. ''In some ways it sounds more like science fiction than fact,'' said Dr. Robert Caldwell, a Dartmouth physicist who described this apocalyptic possibility in a paper with Dr. Marc Kamionkowski and Dr. Nevin Weinberg, from the California Institute of Technology, last year. The Big Rip is only one of a constellation of doomsday possibilities resulting from the discovery by two teams of astronomers six years ago that a mysterious force called dark energy seems to be wrenching the universe apart.
    [Show full text]
  • Dark Energy with W < Ÿ1 Causes a Cosmic Doomsday
    PHYSICAL REVIEW LETTERS week ending VOLUME 91, N UMBER 7 15 AUGUST 2003 Phantom Energy: Dark Energy with w<ÿ1 Causes a Cosmic Doomsday Robert R. Caldwell,1 Marc Kamionkowski,2 and Nevin N. Weinberg2 1Department of Physics & Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, New Hampshire 03755, USA 2Mail Code 130-33, California Institute of Technology, Pasadena, California 91125, USA (Received 20 February 2003; published 13 August 2003) We explore the consequences that follow if the dark energy is phantom energy, in which the sum of the pressure and energy density is negative. The positive phantom-energy density becomes infinite in finite time, overcoming all other forms of matter, such that the gravitational repulsion rapidly brings our brief epoch of cosmic structure to a close. The phantom energy rips apart the Milky Way, solar system, Earth, and ultimately the molecules, atoms, nuclei, and nucleons of which we are composed, before the death of the Universe in a ‘‘big rip.’’ DOI: 10.1103/PhysRevLett.91.071301 PACS numbers: 98.80.Cq Hubble’s discovery of the cosmological expansion, But what about w<ÿ1? Might the convergence to crossed with the mathematical predictions of Friedmann w ÿ1 actually be indicating that w<ÿ1? Why re- and others within Einstein’s general theory of relativity, strict our attention exclusively to w 1? Matter with has long sparked speculation on the ultimate fate of the w<ÿ1, dubbed ‘‘phantom energy’’ [19], has received Universe. In particular, it has been shown that if the increased attention among theorists recently. It certainly matter that fills the Universe can be treated as a pressure- has some strange properties.
    [Show full text]
  • Arxiv:2101.08781V1 [Hep-Ph] 21 Jan 2021
    MI-TH-2135 PASSAT at Future Neutrino Experiments: Hybrid Beam-Dump-Helioscope Facilities to Probe Light Axion-Like Particles P. S. Bhupal Dev,1, ∗ Doojin Kim,2, y Kuver Sinha,3, z and Yongchao Zhang4, 1, x 1Department of Physics and McDonnell Center for the Space Sciences, Washington University, St. Louis, MO 63130, USA 2Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA 3Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA 4School of Physics, Southeast University, Nanjing 211189, China There are broadly three channels to probe axion-like particles (ALPs) produced in the laboratory: through their subsequent decay to Standard Model (SM) particles, their scattering with SM particles, or their subsequent conversion to photons. Decay and scattering are the most commonly explored channels in beam-dump type experiments, while conversion has typically been utilized by light- shining-through-wall (LSW) experiments. A new class of experiments, dubbed PASSAT (Particle Accelerator helioScopes for Slim Axion-like-particle deTection), has been proposed to make use of the ALP-to-photon conversion in a novel way: ALPs, after being produced in a beam-dump setup, turn into photons in a magnetic field placed near the source. It has been shown that such hybrid beam-dump-helioscope experiments can probe regions of parameter space that have not been investigated by other laboratory-based experiments, hence providing complementary information; in particular, they probe a fundamentally different region than decay or LSW experiments. We propose the implementation of PASSAT in future neutrino experiments, taking a DUNE-like experiment as an example.
    [Show full text]
  • Signal Processing in the PVLAS Experiment
    Signal Processing in the PVLAS Experiment E. ZAVATTINI1, G. ZAVATTINI4, G. RUOSO2, E. POLACCO3, E. MILOTTI,1, M. KARUZA1, U. GASTALDI 2, G. DI DOMENICO4, F. DELLA VALLE1, R. CIMINO5, S. CARUSOTTO3, G. CANTATORE1, M. BREGANT1 1 - Università e I.N.F.N. Trieste, Via Valerio 2, 34127 Trieste, ITALY 2 - Lab. Naz.di Legnaro dell’I.N.F.N., Viale dell’Università 2, 35020 Legnaro, ITALY 3 - Università e I.N.F.N. Pisa, Via F. Buonarroti 2, 56100 Pisa, ITALY 4 - Università e I.N.F.N. Ferrara, Via del Paradiso 12, 44100 Ferrara, ITALY 5 - Lab. Naz.di Frascati dell’I.N.F.N., Via E. Fermi 40, 00044 Frascati, ITALY [email protected] http://www.ts.infn.it/experiments/pvlas/ Abstract: - Nonlinear interactions of light with light are well known in quantum electronics, and it is quite common to generate harmonic or subharmonic beams from a primary laser with photonic crystals. One suprising result of quantum electrodynamics is that because of the quantum fluctuations of charged fields, the same can happen in vacuum. The virtual charged particle pairs can be polarized by an external field and vacuum can thus become birefringent: the PVLAS experiment was originally meant to explore this strange quantum regime with optical methods. Since its inception PVLAS has found a new, additional goal: in fact vacuum can become a dichroic medium if we assume that it is filled with light neutral particles that couple to two photons, and thus PVLAS can search for exotic particles as well. PVLAS implements a complex signal processing scheme: here we describe the double data acquisition chain and the data analysis methods used to process the experimental data.
    [Show full text]
  • Axions (A0) and Other Very Light Bosons, Searches for See the Related Review(S): Axions and Other Similar Particles
    Citation: M. Tanabashi et al. (Particle Data Group), Phys. Rev. D 98, 030001 (2018) Axions (A0) and Other Very Light Bosons, Searches for See the related review(s): Axions and Other Similar Particles A0 (Axion) MASS LIMITS from Astrophysics and Cosmology These bounds depend on model-dependent assumptions (i.e. — on a combination of axion parameters). VALUE (MeV) DOCUMENT ID TECN COMMENT We do not use the following data for averages, fits, limits, etc. ••• ••• >0.2 BARROSO 82 ASTR Standard Axion >0.25 1 RAFFELT 82 ASTR Standard Axion >0.2 2 DICUS 78C ASTR Standard Axion MIKAELIAN 78 ASTR Stellar emission >0.3 2 SATO 78 ASTR Standard Axion >0.2 VYSOTSKII 78 ASTR Standard Axion 1 Lower bound from 5.5 MeV γ-ray line from the sun. 2 Lower bound from requiring the red giants’ stellar evolution not be disrupted by axion emission. A0 (Axion) and Other Light Boson (X 0) Searches in Hadron Decays Limits are for branching ratios. VALUE CL% DOCUMENT ID TECN COMMENT We do not use the following data for averages, fits, limits, etc. ••• ••• <2 10 10 95 1 AAIJ 17AQ LHCB B+ K+ X 0 (X 0 µ+ µ ) × − → → − <3.7 10 8 90 2 AHN 17 KOTO K0 π0 X 0, m = 135 MeV × − L → X 0 11 3 0 0 + <6 10− 90 BATLEY 17 NA48 K± π± X (X µ µ−) × 4 → 0 0 →+ WON 16 BELL η γ X (X π π−) 9 5 0→ 0 0 → 0 + <1 10− 95 AAIJ 15AZ LHCB B K∗ X (X µ µ−) × 6 6 0 → 0 0 →+ <1.5 10− 90 ADLARSON 13 WASA π γ X (X e e−), × m→ = 100 MeV→ X 0 <2 10 8 90 7 BABUSCI 13B KLOE φ η X0 (X 0 e+ e ) × − → → − 8 ARCHILLI 12 KLOE φ η X0, X 0 e+ e → → − <2 10 15 90 9 GNINENKO 12A BDMP π0 γ X 0 (X 0 e+ e ) × − → → −
    [Show full text]
  • Dark Matter Vienna University of Technology V2.1
    Dark Matter Vienna University of Technology V2.1 Jochen Schieck and Holger Kluck Institut f¨urHochenergiephysik Nikolsdorfer Gasse 18 1050 Wien Atominstitut derTechnischen Universit¨atWien Stadionallee 2 1020 Wien Wintersemester 2017/18 18.12.2017 2 Contents 1 Introduction 7 1.1 What is "Dark Matter" . .7 1.1.1 Dark . .7 1.1.2 Matter . .7 1.1.3 Cosmology . .7 1.1.4 Massive particles as origin of "Dark Matter" . .7 1.1.5 "Dark Matter" as contribution to the energy density of the universe in Cosmology . .7 1.2 First Indication of observing "Dark Matter" . 13 1.3 Brief Introduction to Cosmology . 15 1.3.1 Special Relativity . 16 1.3.2 Differential geometry . 16 1.3.3 General Relativity . 16 1.3.4 Cosmology . 17 1.3.5 Decoupling of matter and radiation . 18 1.4 The Standard Model of Particle Physics . 19 1.4.1 The matter content of the Standard Model . 19 1.4.2 Forces within the Standard Model . 19 1.4.3 Shortcoming of the Standard Model . 20 1.4.4 Microscopic Behaviour of Gravity . 21 2 Evidence 23 2.1 Dynamics of Galaxies . 23 2.2 Gravitational Lensing . 24 2.2.1 Bullet Cluster . 31 2.3 Cosmic Microwave Background . 33 2.4 Primordial Nucleosynthesis (Big Bang Nucleosynthesis - BBN) . 35 3 Structure Evolution 39 3.1 Structure Formation . 39 3.1.1 The Classic Picture . 39 3.1.2 Structure Formation and Cosmology . 41 3.2 Model of the Dark Matter Halo in our Galaxy . 45 3 4 Unsolved Questions and Open Issues 49 4.1 Core-Cusp Problem .
    [Show full text]
  • Dark Matter in Nuclear Physics
    Dark Matter in Nuclear Physics George Fuller (UCSD), Andrew Hime (LANL), Reyco Henning (UNC), Darin Kinion (LLNL), Spencer Klein (LBNL), Stefano Profumo (Caltech) Michael Ramsey-Musolf (Caltech/UW Madison), Robert Stokstad (LBNL) Introduction A transcendent accomplishment of nuclear physics and observational cosmology has been the definitive measurement of the baryon content of the universe. Big Bang Nucleosynthesis calculations, combined with measurements made with the largest new telescopes of the primordial deuterium abundance, have inferred the baryon density of the universe. This result has been confirmed by observations of the anisotropies in the Cosmic Microwave Background. The surprising upshot is that baryons account for only a small fraction of the observed mass and energy in the universe. It is now firmly established that most of the mass-energy in the Universe is comprised of non-luminous and unknown forms. One component of this is the so- called “dark energy”, believed to be responsible for the observed acceleration of the expansion rate of the universe. Another component appears to be composed of non-luminous material with non-relativistic kinematics at the current epoch. The relationship between the dark matter and the dark energy is unknown. Several national studies and task-force reports have found that the identification of the mysterious “dark matter” is one of the most important pursuits in modern science. It is now clear that an explanation for this phenomenon will require some sort of new physics, likely involving a new particle or particles, and in any case involving physics beyond the Standard Model. A large number of dark matter studies, from theory to direct dark matter particle detection, involve nuclear physics and nuclear physicists.
    [Show full text]
  • Gammev: Fermilab Axion-Like Particle Photon Regeneration Results
    GammeV: Fermilab Axion-like Particle Photon Regeneration Results William Wester Fermilab, MS222, Batavia IL, USA presented on behalf of the GammeV Collaboration DOI: http://dx.doi.org/10.3204/DESY-PROC-2008-02/wester william GammeV is an axion-like particle photon regeneration experiment conducted at Fermilab that employs the light shining through a wall technique. We obtain limits on the cou- pling of a photon to an axion-like particle that extend previous limits for both scalar and pseudoscalar axion-like particles in the milli-eV mass range. We are able to exclude the axion-like particle interpretation of the anomalous PVLAS 2006 result by more than 5 standard deviations. 1 Introduction The question, What are the particles that make up the dark matter of the universe?, is one of the most fundamental scientific questions today. Besides weakly interacting massive particles (WIMPs) such as neutralinos, axion-like particles or other weakly interacting sub-eV particles (WISPs) are highly motivated dark matter particle candidates since they have properties that might explain the cosmic abundance of dark matter. The milli-eV mass scale is of particular interest in modern particle physics since that mass scale may be constructed with a see-saw between the Planck and TeV mass scales, and may be related to neutrino mass differences, the dark energy density expressed in (milli-eV)4, and known dark matter candidates such as gravitinos and axion-like particles. In 2006, the PVLAS experiment reported [1] anomalous polarization effects in the presence of a magnetic field including polarization rotation and el- lipticity generation that could be interpreted as being mediated by an axion-like particle in the milli-eV mass range with a unexpectedly strong coupling to photons.
    [Show full text]