DOCSLIB.ORG

Cosmology and Dark Matter Lecture 2

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cosmology and Dark Matter Lecture 2 1 Cosmology and Dark Matter V.A. Rubakov Lecture 2 2 Outline of Lecture 2 WIMP search Dark matter axions Theory Cosmology Search Fuzzy dark matter Warm dark matter Sterile neutrino Gravitino Dark matter summary 3 WIMP search: direct Difficulties in direct search for WIMPs Recoil energy of nucleus A 1 2 2 10 100 Erec . MAvX 2 keV (1 + MA/MX ) ∼ ÷ vX 200 km/s = WIMP velocity in our Galaxy. ≃ Rate in detector of mass Mdet (spin-independent) 23 ρloc 2 6 10 Mdet Γ vX (σNA ) · ≃ MX A g 100 σ 0 2events GeV A Mdet N . 100 10 45 2 ≃ yr · MX tonn − cm 3 ρloc 0.4 GeV/cm = local DM mass density. ≃ 4 Direct searches 5 SUSY neutralino strongly constrained NB: gray points require a lot of fine-tuning. 6 The LHC is sensitive to WIMPs spin-independent spin-dependent µ 5 µ 5 X¯ γµ X q¯γ q X¯ γµ γ X q¯γ γ q · · 2 σAX ∝ A σAX ∝ JA(JA + 1) 7 Indirect searches DM annihilation in centers of Sun, Earth ¯ X + X π± , K± + ... ν , ν¯ + ... → → High Baksan Underground Scintillation Telescope energy = ⇒ Super-K neutrinos IceCube Baikal GVD DM annihilation in space e+, p¯ in cosmic rays (PAMELA, AMS), annihilation γ’s (Fermi-LAT, MAGIC, HESS, CTA ...). 8 Limits from annihilation γ’s -24 10 χχ bb (CMB) -25 H.E.S.S. 10 Planck (Einasto) /s) 3 (NFW) thermal DM CTA (cm 〉 v (dSphs) -26 (Albert+, 2016) (Einasto) 〈σ 10 CTA Fermi-LAT Fermi-LAT+MAGIC (NFWc) Fermi-LAT(45dSphs,15y) -27 10 Fermi-LAT 10 10 2 10 3 10 4 mχ (GeV) Current limits, solid Projected limits, dashed NFW, Einasto: dark matter profiles in galaxies Thermal DM: WIMP annihilation cross section, assuming domination of X bb¯ → 9 TeV SCALE PHYSICS MAY WELL BE RESPONSIBLE FOR GENERATION OF DARK MATTER Is this guaranteed? By no means. Other good DM candidates: axion, sterile neutrino, gravitino Plus a lot of exotica... 10 Axions Motivation: solution of strong CP problem What’s the problem? Point No. 1: global symmetries of QCD in chiral limit mu = md = ms = 0 1 a aµν ¯ γ µ LQCD,m=0 = 4Gµν G +∑qii Dµ qi − i 1 a aµν µ µ = Gµν G +∑ q¯L iiγ Dµ qL i + q¯R iiγ Dµ qR i −4 , , , , i Naively: symmetry under independent SU(3) U(1) rotations of left and right quarks, × SU(3)L U(1)L SU(3)R U(1)R = SU(3)L SU(3)R U(1)B U(1)A × × × × × × iα iβγ5 U(1)B: qi e qi; U(1)A: qi e qi → → 11 Symmetry partially broken due to quark condensate in QCD vacuum, ¯ 1 3 u¯LuR = dLdR = qq¯ Λ h i h i 2h i ∼ QCD Remaining symmetry SU(3)V : rotates left and right quarks together; U(1)B Expect 9 Nambu–Goldstone bosons, 8 from SU(3)L SU(3)R SU(3)V plus 1 from U(1)B U(1)A U(1)B. × → × → 0 ¯ 0 But there are only 8 in Nature: π±, π , K±, K0, K , η. 2 2 NB: mπ = mu d qq¯ / fπ , h i η′ is heavy, does not behave like Nambu–Goldstone boson. Reason: U(1)A is not a symmetry in QCD A Axial current has triangle anomaly, ∂µ Jµ = 0. 6 12 Point No. 2 Quark Yukawa interactions = quark mass matrix ⇒ (d) ¯i j (u) ¯i j (d) ¯i j (u) i j LY = y Q Hd + y Q H∗u + h.c. = Lm = m d d + m u¯ u + h.c. ij L R ij L R ⇒ ij L R ij L R (u,d) (u,d) 2 1 2 3 mij = yij v/√ complex; i, j = , , = generation label. Standard lore: diagonalize = CKM matrix, 3 angles, 1 phase. ⇒ This is not quite true 13 One more phase: common phase of all Yukawa couplings/masses, iθ CKM mij = e m or θ=(Arg det m)/3 · ij At first sight: rotate away, 5 qi eiθ/2qi , qi e iθ/2qi , i.e., qi e iγ θ/2qi L → L R → − R → − But this is not allowed: U(1)A is not a symmetry! θ is a physical parameter Yet another subtlety: can have a term in QCD Lagrangian α s θ ε µνλρ a a 16π 0 Gµν Gλρ What matters is θ0 + Arg det m In what follows: θ0 moved to quark mass matrix. 14 Vacuum energy density for non-zero θ, call it V(θ) (useful in what follows). Keep only u,d-quarks, take their masses equal for simplicity, mu = md mq 4 MeV (heavier quarks less important), ≡ ∼ iθ ¯ Lm = e mq(u¯LuR + dLdR) + h.c. Perturbation theory in mq: V(θ)= Lm . Recall quark condensate −h i ¯ 1 3 u¯LuR = dLdR = qq¯ = real Λ h i h i 2h i ∼ QCD NB: No arbitrary phase here, otherwise η′ would be pseudo-Nambu–Goldstone boson! Get 2 2 mπ fπ V(θ) = Lm = mq qq¯ cosθ= cosθ −h i − h i − 4 θ is a physical parameter! Violates CP. NB: Minimum of V(θ) is at θ = 0. No use if θ is just a parameter. NB: V(θ) more complicated for mu = md. 6 15 26 CP-violation within QCD. Neutron edm dn < 3 10 e cm = · − · ⇒ 10 θ . 10− Strong CP problem. Fine tuning? Mechanism that ensures θ = 0 Peccei–Quinn: promote θ to a field. Simple version: two Englert–Brout–Higgs fields, Y1 = 1, Y2 = 1: − (d) ¯ (u) ¯ 2 2 L = y QLH1dR + y QLH2uR + Dµ H1 + Dµ H2 V(H1,H2) | | | | − Classical level: require global U(1)PQ symmetry (PQ symmetry) 5 i iγ θ/2 i iθ iθ q e q , H1 e H1 , H2 e H2 → → → Vev’s: H1 = v1/√2, H2 = v2/√2, break PQ symmetry spontaneously.h i h i 16 Parametrize iθ(x) iθ(x) H1 = e v1/√2 , H2 = e v2√2 If not for QCD, θ(x) would be a massless Nambu–Goldstone boson, axion. Kinetic term 1 1 1 2 ∂ θ 2 2 ∂ θ 2 2 ∂ θ 2 2v1( µ ) + 2v2( µ ) = 2 fPQ( µ ) i θ(x) Quark masses md,u = yd,uv1,2e h i. Turn on QCD: shift θ θ + const is NOT a symmetry. → Consequences θ(x) is such that V(θ) is at minimum = θ = 0 automatically.h i Strong CP problem solved.⇒ θ(x) gets a mass 17 1 2 2 1 2 Lθ = f (∂µθ) V(θ) , V(θ) mq qq¯ cosθ = mq qq¯ θ 2 PQ − ≃ − h i 2 h i Axion field θ(x) = a(x)/ fPQ: 2 2 12 m qq¯ mπ fπ 10 GeV m2 q m 6 10 6 eV a h2 i 4 2 = a = − ≃ fPQ ≃ fPQ ⇒ · · fPQ Interactions: Axion-photon-photon α α a(x) Caγγ θ εµνλρFµν Fλρ =Caγγ (~E H~ ) , Caγγ 1 roughly 16π · 2π fPQ · ∼ 18 Two Englert–Brout–Higgs fields are not enough 2 2 fPQ= v1 + v2 = 246 GeV too small: q (Weinberg–Wilczek) axion is too heavy (ma 15 keV), its couplings too large, ruled out experimentally.∼ Add heavy fields, make fPQ large. Dine–Fischler–Srednicki–Zhitnitsky (DFSZ); Kim–Shifman–Vainshtein–Zakharov (KSVZ) General picture: PQ field Φ(x) = ρ(x)eiθ(x), vev Φ = fPQ h i axion field a(x) = θ(x)/ fPQ m qq¯ ∂ Φ 2 ¯ θ 2 2 ∂ θ 2 ¯ θ 2 ∂ 2 q 2 ( µ ) mq qq ( ) + = fPQ( µ ) mq qq = ( µa) h2 ia − h i ··· − h i − fPQ Light axions, interact very weakly 19 To summarize Peccei–Quinn solution to strong CP problem predicts axion with mass 1012 GeV ma = 6 µeV · fPQ and aγγ interaction α a(x) Caγγ (~E H~ ) 2π fPQ · where Caγγ 1 is model-dependent, and fPQ is the only free ∼ parameter. Larger fPQ = smaller ma, weaker interactions. ⇒ 20 Why is this interesting for cosmology? Axion is practically stable: 5 α 2 m3 eV Γ a γγ C2 a τ 1017 yrs ( ) = aγγ 8π 4π 2 = a = → fPQ ⇒ ma Interacts very weakly = dark matter candidate ⇒ May never be in thermal equilibrium = cold dark matter if momenta are negligibly small. ⇒ Q. How can one arrange for negligibly small momenta for particles with sub-eV masses? A. Condensates (not the only option) 21 Axion production: misalignment Recall V(θ) mq qq¯ cosθ ≃ − h i Early Universe, high T: qq¯ = 0 = V(θ) = 0. h i ⇒ No preferred value of θ = Initial condinion θ0 anywhere between π and⇒π. − At QCD epoch (T 200 MeV) potential V(θ) builds up. θ starts to roll down. ∼ V(θ) V(θ) • • 0θ0 2π θ θ high T lower T 22 Estimating axion mass density Rolling down starts when ma(T) H(T): before that time scale of ∼ rolling m 1 is larger than the cosmological time scale H 1. a− ∼ − After initial rolling, θ oscillates about minimum θ = 0. Homogeneous oscillating field = condensate = collection of quanta with zero spatial momentum. Just what we need for cold dark matter! Estimate for present mass density: Energy density at beginning of rolling 2 2 2 2 2 V(θ0,T) m (T)a0 = m (T) f θ0 ≃ a a PQ Number density of quanta at that time 2 2 na(T) V(θ0,T)/ma(T) = ma(T) f θ0 ≃ PQ 23 2 Recall ma(T) H(T) = T /M = number-to-entropy ∼ Pl∗ ⇒ H(T) f 2 θ 2 f 2 θ 2 na # PQ 0 # PQ 0 = 3 = s g T √g MPlT ∗ ∗ with T = TQCD 200 MeV and # 1.
Load more

Recommended publications
  • Letter of Interest Cosmic Probes of Ultra-Light Axion Dark Matter
    Snowmass2021 - Letter of Interest Cosmic probes of ultra-light axion dark matter Thematic Areas: (check all that apply /) (CF1) Dark Matter: Particle Like (CF2) Dark Matter: Wavelike (CF3) Dark Matter: Cosmic Probes (CF4) Dark Energy and Cosmic Acceleration: The Modern Universe (CF5) Dark Energy and Cosmic Acceleration: Cosmic Dawn and Before (CF6) Dark Energy and Cosmic Acceleration: Complementarity of Probes and New Facilities (CF7) Cosmic Probes of Fundamental Physics (TF09) Astro-particle physics and cosmology Contact Information: Name (Institution) [email]: Keir K. Rogers (Oskar Klein Centre for Cosmoparticle Physics, Stockholm University; Dunlap Institute, University of Toronto) [ [email protected]] Authors: Simeon Bird (UC Riverside), Simon Birrer (Stanford University), Djuna Croon (TRIUMF), Alex Drlica-Wagner (Fermilab, University of Chicago), Jeff A. Dror (UC Berkeley, Lawrence Berkeley National Laboratory), Daniel Grin (Haverford College), David J. E. Marsh (Georg-August University Goettingen), Philip Mocz (Princeton), Ethan Nadler (Stanford), Chanda Prescod-Weinstein (University of New Hamp- shire), Keir K. Rogers (Oskar Klein Centre for Cosmoparticle Physics, Stockholm University; Dunlap Insti- tute, University of Toronto), Katelin Schutz (MIT), Neelima Sehgal (Stony Brook University), Yu-Dai Tsai (Fermilab), Tien-Tien Yu (University of Oregon), Yimin Zhong (University of Chicago). Abstract: Ultra-light axions are a compelling dark matter candidate, motivated by the string axiverse, the strong CP problem in QCD, and possible tensions in the CDM model. They are hard to probe experimentally, and so cosmological/astrophysical observations are very sensitive to the distinctive gravitational phenomena of ULA dark matter. There is the prospect of probing fifteen orders of magnitude in mass, often down to sub-percent contributions to the DM in the next ten to twenty years.
    [Show full text]
  • X-Ray Line Signal from Decaying Axino Warm Dark Matter
    Physics Letters B 735 (2014) 92–94 Contents lists available at ScienceDirect Physics Letters B www.elsevier.com/locate/physletb X-ray line signal from decaying axino warm dark matter ∗ Ki-Young Choi a, , Osamu Seto b a Korea Astronomy and Space Science Institute, Daejon 305-348, Republic of Korea b Department of Life Science and Technology, Hokkai-Gakuen University, Sapporo 062-8605, Japan a r t i c l e i n f o a b s t r a c t Article history: We consider axino warm dark matter in a supersymmetric axion model with R-parity violation. In this Received 11 March 2014 scenario, axino with the mass ma˜ 7keVcan decay into photon and neutrino resulting in the X-ray line Received in revised form 14 May 2014 signal at 3.5 keV, which might be the origin of unidentified X-ray emissions from galaxy clusters and Accepted 3 June 2014 Andromeda galaxy detected by the XMM-Newton X-ray observatory. Available online 6 June 2014 © 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license Editor: A. Ringwald 3 (http://creativecommons.org/licenses/by/3.0/). Funded by SCOAP . 1. Introduction In Section 2 we introduce the model of axino dark matter and in Section 3 we consider the R-parity violation and decay of axinos. Various astrophysical and cosmological observations provide We summarize in Section 4. convincing evidences for the existence of dark matter (DM). Dark matter distribution spans in wide range of scales from galaxy to 2.
    [Show full text]
  • Sterile Neutrinos As Dark Matter
    Sterile neutrinos as dark matter Alexey Boyarsky October 23, 2018 1 / 36 Neutrino dark matter Neutrino seems to be a perfect dark matter candidate: neutral, long-lived, massive, abundantly produced in the early Universe Cosmic neutrinos I We know how neutrinos interact and we can compute their 3 primordial number density nν = 112 cm− (per flavour) I To give correct dark matter abundance the sum of neutrino masses, P m , should be P m 11 eV ν ν ∼ Tremaine-Gunn bound (1979) I Such light neutrinos cannot form small galaxies { one would have to put too many of them and violated Pauli exclusion principle I Minimal mass for fermion dark matter 300 400 eV ∼ − I If particles with such mass were weakly interacting (like neutrino) { they would overclose the Universe 2 / 36 "Between friends" I The final blow to neutrino as dark matter came in mid-80s when M. Davis, G. Efstathiou, C. Frenk, S. White, et al. \Clustering in a neutrino-dominated universe" I They argued that structure formation in the neutrino dominated Universe (with masses around 100 eV would be incompatible with the observations) http://www.adsabs.harvard.edu/abs/1983ApJ...274L...1W Abstract The nonlinear growth of structure in a universe dominated by massive neutrinos using initial conditions derived from detailed linear calculations of earlier evolution has been simulated The conventional neutrino-dominated picture appears to be ruled out. 3 / 36 Two generalizations of neutrino DM I Dark matter cannot be both light and weakly interacting at the same time I To satisfy Tremaine-Gunn
    [Show full text]
  • Closing the Window on Warm Dark Matter
    View metadata, citation and similar papers at core.ac.uk LAPTH-852/01; astro-ph/0106108brought to you by CORE provided by CERN Document Server Closing the Window on Warm Dark Matter Steen H. Hansen1, Julien Lesgourgues2, Sergio Pastor3, Joseph Silk1 1 Department of Physics, Nuclear & Astrophysics Laboratory, University of Oxford, Keble Road, Oxford OX1 3RH, U.K. 2 Laboratoire de Physique Th´eorique LAPTH, B.P. 110, F-74941 Annecy-le-Vieux Cedex, France 3 Max-Planck-Institut f¨ur Physik (Werner-Heisenberg-Institut), F¨ohringer Ring 6, D-80805, Munich, Germany Sterile neutrinos may be one of the best Warm Dark Matter candidates we have today. Both lower and upper bounds on the mass of the sterile neutrino come from astronomical observations. We show that the proper inclusion of the neutrino momentum distribution and the solution of the kinetic equations with the correct coherence breaking terms lead to the near exclusion of the sterile neutrino as a dark matter candidate. PACS number(s): 14.60.Pq, 14.60.St, 95.35.+d I. INTRODUCTION do massless neutrinos. Therefore they do not share the entropy release from the successive particle annihilations. Astrophysics provides an increasing amount of inde- Since they were relativistic at decoupling, their distribu- pendent indications that the dark matter of the universe tion function in momentum space is subsequently that of is warm, so that the small-scale fluctuations are damped a massless fermion, but with a temperature, TW , which out by free streaming. This is most easily achieved by is given today by giving a keV mass to the DM particle, in which case the 1=3 preferred candidate is the sterile neutrino.
    [Show full text]
  • Warm Dark Matter
    Cosmology in the Nonlinear Domain: Warm Dark Matter Katarina Markoviˇc M¨unchen 2012 Cosmology in the Nonlinear Domain: Warm Dark Matter Katarina Markoviˇc Dissertation an der Fakult¨atf¨urPhysik der Ludwig{Maximilians{Universit¨at M¨unchen vorgelegt von Katarina Markoviˇc aus Ljubljana, Slowenien M¨unchen, den 17.12.2012 Erstgutachter: Prof. Dr. Jochen Weller Zweitgutachter: Prof. Dr. Andreas Burkert Tag der m¨undlichen Pr¨ufung:01.02.2013 Abstract The introduction of a so-called dark sector in cosmology resolved many inconsistencies be- tween cosmological theory and observation, but it also triggered many new questions. Dark Matter (DM) explained gravitational effects beyond what is accounted for by observed lumi- nous matter and Dark Energy (DE) accounted for the observed accelerated expansion of the universe. The most sought after discoveries in the field would give insight into the nature of these dark components. Dark Matter is considered to be the better established of the two, but the understanding of its nature may still lay far in the future. This thesis is concerned with explaining and eliminating the discrepancies between the current theoretical model, the standard model of cosmology, containing the cosmological constant (Λ) as the driver of accelerated expansion and Cold Dark Matter (CDM) as main source of gravitational effects, and available observational evidence pertaining to the dark sector. In particular, we focus on the small, galaxy-sized scales and below, where N-body simulations of cosmological structure in the ΛCDM universe predict much more structure and therefore much more power in the matter power spectrum than what is found by a range of different observations.
    [Show full text]
  • Supersymmetric Dark Matter Candidates in Light of Constraints from Collider and Astroparticle Observables Jonathan Da Silva
    Supersymmetric Dark Matter candidates in light of constraints from collider and astroparticle observables Jonathan da Silva To cite this version: Jonathan da Silva. Supersymmetric Dark Matter candidates in light of constraints from collider and astroparticle observables. High Energy Physics - Phenomenology [hep-ph]. Université de Grenoble, 2013. English. NNT : 2013GRENY033. tel-00912650v2 HAL Id: tel-00912650 https://tel.archives-ouvertes.fr/tel-00912650v2 Submitted on 19 Jan 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. THESE` Pour obtenir le grade de DOCTEUR DE L’UNIVERSITE´ DE GRENOBLE Specialit´ e´ : Physique Theorique´ Arretˆ e´ ministeriel´ : 7 aoutˆ 2006 Present´ ee´ par Jonathan DA SILVA These` dirigee´ par Genevieve` BELANGER´ prepar´ ee´ au sein du Laboratoire d’Annecy-le-Vieux de Physique Theorique´ (LAPTh) et de l’Ecole´ Doctorale de Physique de Grenoble Supersymmetric Dark Matter candidates in light of constraints from collider and astroparticle observables These` soutenue publiquement le 3 juillet 2013, devant le jury compose´ de : Dr. Rohini GODBOLE Professeur, CHEP Bangalore, Inde, Presidente´ Dr. Farvah Nazila MAHMOUDI Maˆıtre de Conferences,´ LPC Clermont, Rapporteur Dr. Ulrich ELLWANGER Professeur, LPT Orsay, Rapporteur Dr. Celine´ BŒHM Charge´ de recherche, Durham University, Royaume-Uni, Examinatrice Dr.
    [Show full text]
  • Gamma-Ray Line Emission from OB Associations and Young Open Knödlseder, J
    Title Authors Reference ---2002--- Gamma-ray line emission from OB associations and young open KnÖdlseder, J. et al. A&A 390, 945-960 (2002) clusters. II. The Cygnus region Detectability and characteristics of the 2.223 MeV line emission from Guessoum, N, & Jean, P. A&A, 396, 157-169 (2002) nearby X-ray binaries New Astronomy Reviews, Volume 46, Gamma-ray lines in advection dominated accretion flows Prantzos, N. Issue 8-10, p. 567-571 (2002) New Astronomy Reviews, Volume 46, SPI cosmic radioactivity measurements in perspective Schoenfelder, V. Issue 8-10, p. 597-604 (2002) Pre-launch calibration campaign of the gamma-ray spectrometer aboard New Astronomy Reviews, Volume 46, Schanne, S. the INTEGRAL satellite Issue 8-10, p. 605-609 (2002) New Astronomy Reviews, Volume 46, Instrumental lines of astrophysical relevance in TGRS and SPI Weidenspointner, G. et al. Issue 8-10, p. 625-629 (2002) Proceedings of the XXII Moriond Coded-Mask Imaging in Gamma-Ray Astronomy - Separating the Real Astrophysics Meeting The Gamma- Skinner, G.K. and Imaginary parts of a Complex subject Ray Universe (Les Arcs, March 9-16, 2002) Proceedings of the XXII Moriond Astrophysics Meeting The Gamma Observation of Gamma-ray Bursts with INTEGRAL Gotz, D. & Mereghetti, S. Ray Universe (Les Arcs, March 9-16, 2002) Proceedings of the XXII Moriond Astrophysics Meeting The Gamma- The INTEGRAL Science Data Centre Beckmann, V. Ray Universe (Les Arcs, March 9-16, 2002) Proceedings of the XXII Moriond Astrophysics Meeting The Gamma- The INTEGRAL Mission Hermsen, W. & Winkler, C. Ray Universe (Les Arcs, March 9-16, 2002) Proceedings of the XXII Moriond Astrophysics Meeting The Gamma- IBIS/PICsIT Data and Analysis Stephen, J.B.
    [Show full text]
  • Interacting Warm Dark Matter Allows These Two Possibilities and So It Assumes from the Beginning a Positive Eos Constant
    Prepared for submission to JCAP Interacting warm dark matter Norman Cruz,a Guillermo Palma,a David Zambranoa and Arturo Avelinob aDepartamento de F´ısica, Facultad de Ciencia, Universidad de Santiago de Chile, Casilla 307, Santiago, Chile. bDepartamento de F´ısica, DCI, Campus Le´on, Universidad de Guanajuato, CP. 37150, Le´on, Guanajuato, M´exico. E-mail: [email protected] Abstract. We explore a cosmological model composed by a dark matter fluid interacting α β with a dark energy fluid. The interaction term has the non-linear λρmρe form, where ρm and ρe are the energy densities of the dark matter and dark energy, respectively. The parameters α and β are in principle not constrained to take any particular values, and were estimated from observations. We perform an analytical study of the evolution equations, finding the fixed points and their stability properties in order to characterize suitable physical regions in the phase space of the dark matter and dark energy densities. The constants (λ, α, β) as well as wm and we of the EoS of dark matter and dark energy respectively, were estimated using the cosmological observations of the type Ia supernovae and the Hubble expansion rate H(z) data sets. We find that the best estimated values for the free parameters of the model correspond to a warm dark matter interacting with a phantom dark energy component, with a well goodness-of-fit to data. However, using the Bayesian Information Criterion (BIC) we find that this model is overcame by a warm dark matter – phantom dark energy model without interaction, as well as by the ΛCDM model.
    [Show full text]
  • Constraining Nonthermal Dark Matter's Impact on the Matter Power
    Constraining Nonthermal Dark Matter’s Impact on the Matter Power Spectrum Carisa Miller∗ and Adrienne L. Erickcek† Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Phillips Hall CB3255, Chapel Hill, NC 27599 USA Riccardo Murgia‡ SISSA, Via Bonomea 265, 34136 Trieste, Italy INFN, Sezione di Trieste, via Valerio 2, 34127 Trieste, Italy and IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy The inclusion of a period of (effective) matter domination following inflation and prior to the onset of radiation domination has interesting and observable consequences for structure growth. During this early matter-dominated era (EMDE), the Universe was dominated by massive particles, or an oscillating scalar field, that decayed into Standard Model particles, thus reheating the Universe. This decay process could also be the primary source of dark matter. In the absence of fine-tuning between the masses of the parent and daughter particles, both dark matter particles and Standard Model particles would be produced with relativistic velocities. We investigate the effects of the nonthermal production of dark matter particles with relativistic velocities on the matter power spectrum by determining the resulting velocity distribution function for the dark matter. We find that the vast majority of dark matter particles produced during the EMDE are still relativistic at reheating, so their free streaming erases the perturbations that grow during the EMDE. The free streaming of the dark matter particles can also prevent the formation of satellite galaxies around the Milky Way and the structures observed in the Lyman-α forest. For a given reheat temperature, these observations put an upper limit on the velocity of the dark matter particles at their creation.
    [Show full text]
  • Sterile Neutrino Dark Matter
    Sterile Neutrino Dark Matter A. Boyarskya, M. Drewesb,c, T. Lasserred,e,f,g, S. Mertensf,h, O. Ruchayskiyi aUniversiteit Leiden - Instituut Lorentz for Theoretical Physics, P.O. Box 9506, NL-2300 RA Leiden, Netherlands bCentre for Cosmology, Particle Physics and Phenomenology, Universit´ecatholique de Louvain, Louvain-la-Neuve B-1348, Belgium cExcellence Cluster Universe, Boltzmannstr. 2, D-85748, Garching, Germany dCommissariat `al'´energie atomique et aux ´energies alternatives, Centre de Saclay,DRF/IRFU, 91191 Gif-sur-Yvette, France eInstitute for Advance Study, Technische Universit¨atM¨unchen,James-Franck-Str. 1, 85748 Garching fPhysik-Department, Technische Universit¨atM¨unchen,James-Franck-Str. 1, 85748 Garching gAstroParticule et Cosmologie, Universit´eParis Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cit´e,75205 Paris Cedex 13, France hMax-Planck-Institut f¨urPhysik (Werner-Heisenberg-Institut), Foehringer Ring 6, 80805 M¨unchen, Germany iDiscovery Center, Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK-2100 Copenhagen, Denmark Abstract We review sterile neutrinos as possible Dark Matter candidates. After a short summary on the role of neutrinos in cosmology and particle physics, we give a comprehensive overview of the current status of the research on sterile neutrino Dark Matter. First we discuss the motivation and limits obtained through astrophysical observations. Second, we review different mechanisms of how sterile neutrino Dark Matter could have been produced in the early universe.
    [Show full text]
  • Sterile Neutrino, Hidden Dark Matter and Their Cosmological Signatures
    International Conference on Modern Perspectives of Cosmology and Gravitation (COSGRAV12) IOP Publishing Journal of Physics: Conference Series 405 (2012) 012011 doi:10.1088/1742-6596/405/1/012011 Sterile neutrino, hidden dark matter and their cosmological signatures Subinoy Das Institut f¨ur Theoretische Teilchenphysik und Kosmologie RWTH Aachen, D-52056 Aachen, Germany E-mail: [email protected] Abstract. Though thermal dark matter has been the central idea behind the dark matter candidates, it is highly possible that dark matter of the universe is non-thermal in origin or it might be in thermal contact with some hidden or dark sector but not with standard model. Here we explore the cosmological bounds as well as the signatures on two types of non-thermal dark matter candidates. First we discuss a hidden dark matter with almost no interaction (or very feeble) with standard model particles so that it is not in thermal contact with visible sector but we assume it is thermalized with in a hidden sector due to some interaction. While encompassing the standard cold WIMP scenario, we do not require the freeze-out process to be non-relativistic. Rather, freeze-out may also occur when dark matter particles are semi-relativistic or relativistic. Especially we focus on the warm dark matter scenario in this set up and find the constraints on the warm dark matter mass, cross-section and hidden to visible sector temperature ratio which accounts for the observed dark-matter density, satisfies the Tremaine-Gunn bound on dark-matter phase space density and has a free-streaming length consistent with cosmological constraints on the matter power spectrum.
    [Show full text]
  • Sterile Neutrinos As Warm Dark Matter
    Sterile Neutrinos as Warm Dark Matter Manfred Lindner What is ν – June 25-29 M. Lindner, MPIK GGI, Florence, June 25-29, 2012 1 SM works perfectly & Higgs Mass Range is converging - allowed mass range is shrinking… - if SM Higgs exists light - no (clear) signs for anything else just the SM? A ‘peak’ at 126 GeV ??? Dark Matter? M. Lindner, MPIK GGI, Florence, June 25-29, 2012 2 Triviality and Vacuum Stability Λ(GeV) 126 GeV < mH < 174 GeV SM does not exist w/o embedding - U(1) copling , Higgs self-coupling λ triviality 126 GeV is here! allowed λ(Mpl)=0 vacuum stavility - just SM??? ln(µ) Λ ML ‘86 - hierarchy problem Holthausen, ML, Lim RGE arguments seem to work we need some embedding M. Lindner, MPIK GGI, Florence, June 25-29, 2012 3 The SM works perfect but must be extended…. • Hierarchy problem - separation of two scalar scales is unstable… SUSY, TeV physics - Planck scale physics: New concepts … ??? • Many theoretical reasons for BSM physics… • SM cannot explain Baryon Asymmetry of the Universe (BAU) BUT: Massive neutrinos require SM extension SM+ leptogenesis = one of the best BAU explanations nothing else needed! • Dark Matter - an extra particle is needed which is DM - particles connected to the hierarchy problem, strong CP, … - massive neutrinos require new physics DM? M. Lindner, MPIK GGI, Florence, June 25-29, 2012 4 Most favoured Dark Matter: WIMPs • Candidates in BSM models hierarchy problem • WIMP miracle correct abundance • MSSM neutralino: Level of fine-tuning Δtot XENON100-2010 XENON100-2012 ??? XENON1T * becoming more tuned… * other candiates..? BSM neutrinos? P.
    [Show full text]