Lecture 17 : the Cosmic Microwave Background
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1 Lecture 26
PHYS 445 Lecture 26 - Black-body radiation I 26 - 1 Lecture 26 - Black-body radiation I What's Important: · number density · energy density Text: Reif In our previous discussion of photons, we established that the mean number of photons with energy i is 1 n = (26.1) i eß i - 1 Here, the questions that we want to address about photons are: · what is their number density · what is their energy density · what is their pressure? Number density n Eq. (26.1) is written in the language of discrete states. The first thing we need to do is replace the sum by an integral over photon momentum states: 3 S i ® ò d p Of course, it isn't quite this simple because the density-of-states issue that we introduced before: for every spin state there is one phase space state for every h 3, so the proper replacement more like 3 3 3 S i ® (1/h ) ò d p ò d r The units now work: the left hand side is a number, and so is the right hand side. But this expression ignores spin - it just deals with the states in phase space. For every photon momentum, there are two ways of arranging its polarization (i.e., the orientation of its electric or magnetic field vectors): where the photon momentum vector is perpendicular to the plane. Thus, we have 3 3 3 S i ® (2/h ) ò d p ò d r. (26.2) Assuming that our system is spatially uniform, the position integral can be replaced by the volume ò d 3r = V. -
Baryogenesis and Dark Matter from B Mesons: B-Mesogenesis
Baryogenesis and Dark Matter from B Mesons: B-Mesogenesis Miguel Escudero Abenza [email protected] arXiv:1810.00880, PRD 99, 035031 (2019) with: Gilly Elor & Ann Nelson Based on: arXiv:2101.XXXXX with: Gonzalo Alonso-Álvarez & Gilly Elor New Trends in Dark Matter 09-12-2020 The Universe Baryonic Matter 5% 26% Dark Matter 69% Dark Energy Planck 2018 1807.06209 Miguel Escudero (TUM) B-Mesogenesis New Trends in DM 09-12-20 !2 Theoretical Understanding? Motivating Question: What fraction of the Energy Density of the Universe comes from Physics Beyond the Standard Model? 99.85%! Miguel Escudero (TUM) B-Mesogenesis New Trends in DM 09-12-20 !3 SM Prediction: Neutrinos 40% 60% Photons Miguel Escudero (TUM) B-Mesogenesis New Trends in DM 09-12-20 !4 The Universe Baryonic Matter 5% 26% Dark Matter 69% Dark Energy Planck 2018 1807.06209 Miguel Escudero (TUM) B-Mesogenesis New Trends in DM 09-12-20 !5 Baryogenesis and Dark Matter from B Mesons: B-Mesogenesis arXiv:1810.00880 Elor, Escudero & Nelson 1) Baryogenesis and Dark Matter are linked 2) Baryon asymmetry directly related to B-Meson observables 3) Leads to unique collider signatures 4) Fully testable at current collider experiments Miguel Escudero (TUM) B-Mesogenesis New Trends in DM 09-12-20 !6 Outline 1) B-Mesogenesis 1) C/CP violation 2) Out of equilibrium 3) Baryon number violation? 2) A Minimal Model & Cosmology 3) Implications for Collider Experiments 4) Dark Matter Phenomenology 5) Summary and Outlook Miguel Escudero (TUM) B-Mesogenesis New Trends in DM 09-12-20 !7 Baryogenesis -
The Matter – Antimatter Asymmetry of the Universe and Baryogenesis
The matter – antimatter asymmetry of the universe and baryogenesis Andrew Long Lecture for KICP Cosmology Class Feb 16, 2017 Baryogenesis Reviews in General • Kolb & Wolfram’s Baryon Number Genera.on in the Early Universe (1979) • Rio5o's Theories of Baryogenesis [hep-ph/9807454]} (emphasis on GUT-BG and EW-BG) • Rio5o & Trodden's Recent Progress in Baryogenesis [hep-ph/9901362] (touches on EWBG, GUTBG, and ADBG) • Dine & Kusenko The Origin of the Ma?er-An.ma?er Asymmetry [hep-ph/ 0303065] (emphasis on Affleck-Dine BG) • Cline's Baryogenesis [hep-ph/0609145] (emphasis on EW-BG; cartoons!) Leptogenesis Reviews • Buchmuller, Di Bari, & Plumacher’s Leptogenesis for PeDestrians, [hep-ph/ 0401240] • Buchmulcer, Peccei, & Yanagida's Leptogenesis as the Origin of Ma?er, [hep-ph/ 0502169] Electroweak Baryogenesis Reviews • Cohen, Kaplan, & Nelson's Progress in Electroweak Baryogenesis, [hep-ph/ 9302210] • Trodden's Electroweak Baryogenesis, [hep-ph/9803479] • Petropoulos's Baryogenesis at the Electroweak Phase Transi.on, [hep-ph/ 0304275] • Morrissey & Ramsey-Musolf Electroweak Baryogenesis, [hep-ph/1206.2942] • Konstandin's Quantum Transport anD Electroweak Baryogenesis, [hep-ph/ 1302.6713] Constituents of the Universe formaon of large scale structure (galaxy clusters) stars, planets, dust, people late ame accelerated expansion Image stolen from the Planck website What does “ordinary matter” refer to? Let’s break it down to elementary particles & compare number densities … electron equal, universe is neutral proton x10 billion 3⇣(3) 3 3 n =3 T 168 cm− neutron x7 ⌫ ⇥ 4⇡2 ⌫ ' matter neutrinos photon positron =0 2⇣(3) 3 3 n = T 413 cm− γ ⇡2 CMB ' anti-proton =0 3⇣(3) 3 3 anti-neutron =0 n =3 T 168 cm− ⌫¯ ⇥ 4⇡2 ⌫ ' anti-neutrinos antimatter What is antimatter? First predicted by Dirac (1928). -
Measurement of the Cosmic Microwave Background Radiation at 19 Ghz
Measurement of the Cosmic Microwave Background Radiation at 19 GHz 1 Introduction Measurements of the Cosmic Microwave Background (CMB) radiation dominate modern experimental cosmology: there is no greater source of information about the early universe, and no other single discovery has had a greater impact on the theories of the formation of the cosmos. Observation of the CMB confirmed the Big Bang model of the origin of our universe and gave us a look into the distant past, long before the formation of the very first stars and galaxies. In this lab, we seek to recreate this founding pillar of modern physics. The experiment consists of a temperature measurement of the CMB, which is actually “light” left over from the Big Bang. A radiometer is used to measure the intensity of the sky signal at 19 GHz from the roof of the physics building. A specially designed horn antenna allows you to observe microwave noise from isolated patches of sky, without interference from the relatively hot (and high noise) ground. The radiometer amplifies the power from the horn by a factor of a billion. You will calibrate the radiometer to reduce systematic effects: a cryogenically cooled reference load is periodically measured to catch changes in the gain of the amplifier circuit over time. 2 Overview 2.1 History The first observation of the CMB occurred at the Crawford Hill NJ location of Bell Labs in 1965. Arno Penzias and Robert Wilson, intending to do research in radio astronomy at 21 cm wavelength using a special horn antenna designed for satellite communications, noticed a background noise signal in all of their radiometric measurements. -
Baryogenesis and Dark Matter from B Mesons
Baryogenesis and Dark Matter from B mesons Abstract: In [1] a new mechanism to simultaneously generate the baryon asymmetry of the Universe and the Dark Matter abundance has been proposed. The Standard Model of particle physics succeeds to describe many physical processes and it has been tested to a great accuracy. However, it fails to provide a Dark Matter candidate, a so far undetected component of matter which makes up roughly 25% of the energy budget of the Universe. Furthermore, the question arises why there is a more matter (or baryons) than antimatter in the Universe taking into account that cosmology predicts a Universe with equal parts matter and anti-matter. The mechanism to generate a primordial matter-antimatter asymmetry is called baryogenesis. Any successful mechanism for baryogenesis needs to satisfy the three Sakharov conditions [2]: • violation of charge symmetry and of the combination of charge and parity symmetry • violation of baryon number • departure from thermal equilibrium In this paper [1] a new mechanism for the generation of a baryon asymmetry together with Dark Matter production has been proposed. The mechanism proposed to explain the observed baryon asymetry as well as the pro- duction of dark matter is developed around a fundamental ingredient: a new scalar particle Φ. The Φ particle is massive and would dominate the energy density of the Universe after inflation but prior to the Bing Bang nucleosynthesis. The same particle will directly decay, out of thermal equilibrium, to b=¯b quarks and if the Universe is cool enough ∼ O(10 MeV), the produced b quarks can hadronize and form B-mesons. -
Black Body Radiation
BLACK BODY RADIATION hemispherical Stefan-Boltzmann law This law states that the energy radiated from a black body is proportional to the fourth power of the absolute temperature. Wien Displacement Law FormulaThe Wien's Displacement Law provides the wavelength where the spectral radiance has maximum value. This law states that the black body radiation curve for different temperatures peaks at a wavelength inversely proportional to the temperature. Maximum wavelength = Wien's displacement constant / Temperature The equation is: λmax= b/T Where: λmax: The peak of the wavelength b: Wien's displacement constant. (2.9*10(−3) m K) T: Absolute Temperature in Kelvin. Emissive power The value of the Stefan-Boltzmann constant is approximately 5.67 x 10 -8 watt per meter squared per kelvin to the fourth (W · m -2 · K -4 ). If the radiation emitted normal to the surface and the energy density of radiation is u, then emissive power of the surface E=c u If the radiation is diffuse Emitted uniformly in all directions 1 E= 푐푢 4 Thermal radiation exerts pressure on the surface on which they are Incident. If the intensity of directed beam of radiations incident normally to The surface is I 퐼 Then Pressure P=u= 푐 If the radiation is diffused 1 P= 푢 3 The value of the constant is approximately 1.366 kilowatts per square metre. When the emissivity of non-black surface is constant at all temperatures and throughout the entire range of wavelength, the surface is called Gray Body. PROBLEMS 1. The temperature of a person’s skin is 350 C. -
Origin and Evolution of the Universe Baryogenesis
Physics 224 Spring 2008 Origin and Evolution of the Universe Baryogenesis Lecture 18 - Monday Mar 17 Joel Primack University of California, Santa Cruz Post-Inflation Baryogenesis: generation of excess of baryon (and lepton) number compared to anti-baryon (and anti-lepton) number. in order to create the observed baryon number today it is only necessary to create an excess of about 1 quark and lepton for every ~109 quarks+antiquarks and leptons +antileptons. Other things that might happen Post-Inflation: Breaking of Pecci-Quinn symmetry so that the observable universe is composed of many PQ domains. Formation of cosmic topological defects if their amplitude is small enough not to violate cosmological bounds. There is good evidence that there are no large regions of antimatter (Cohen, De Rujula, and Glashow, 1998). It was Andrei Sakharov (1967) who first suggested that the baryon density might not represent some sort of initial condition, but might be understandable in terms of microphysical laws. He listed three ingredients to such an understanding: 1. Baryon number violation must occur in the fundamental laws. At very early times, if baryon number violating interactions were in equilibrium, then the universe can be said to have “started” with zero baryon number. Starting with zero baryon number, baryon number violating interactions are obviously necessary if the universe is to end up with a non-zero asymmetry. As we will see, apart from the philosophical appeal of these ideas, the success of inflationary theory suggests that, shortly after the big bang, the baryon number was essentially zero. 2. CP-violation: If CP (the product of charge conjugation and parity) is conserved, every reaction which produces a particle will be accompanied by a reaction which produces its antiparticle at precisely the same rate, so no baryon number can be generated. -
Class 12 I : Blackbody Spectra
Class 12 Spectra and the structure of atoms Blackbody spectra and Wien’s law Emission and absorption lines Structure of atoms and the Bohr model I : Blackbody spectra Definition : The spectrum of an object is the distribution of its observed electromagnetic radiation as a function of wavelength or frequency Particularly important example… A blackbody spectrum is that emitted from an idealized dense object in “thermal equilibrium” You don’t have to memorize this! h=6.626x10-34 J/s -23 kB=1.38x10 J/K c=speed of light T=temperature 1 2 Actual spectrum of the Sun compared to a black body 3 Properties of blackbody radiation… The spectrum peaks at Wien’s law The total power emitted per unit surface area of the emitting body is given by finding the area under the blackbody curve… answer is Stephan-Boltzmann Law σ =5.67X10-8 W/m2/K4 (Stephan-Boltzmann constant) II : Emission and absorption line spectra A blackbody spectrum is an example of a continuum spectrum… it is smooth as a function of wavelength Line spectra: An absorption line is a sharp dip in a (continuum) spectrum An emission line is a sharp spike in a spectrum Both phenomena are caused by the interaction of photons with atoms… each atoms imprints a distinct set of lines in a spectrum The precise pattern of emission/absorption lines tells you about the mix of elements as well as temperature and density 4 Solar spectrum… lots of absorption lines 5 Kirchhoffs laws: A solid, liquid or dense gas produces a continuous (blackbody) spectrum A tenuous gas seen against a hot -
Peter Scicluna – Systematic Effects in Dust-Mass Determinations
The other side of the equation Systematic effects in the determination of dust masses Peter Scicluna ASIAA JCMT Users’ Meeting, Nanjing, 13th February 2017 Peter Scicluna JCMT Users’ Meeting, Nanjing, 13th February 2017 1 / 9 Done for LMC (Reibel+ 2012), SMC (Srinivasan+2016) Total dust mass ∼ integrated dust production over Hubble time What about dust destruction? Dust growth in the ISM? Are the masses really correct? The dust budget crisis: locally Measure dust masses in FIR/sub-mm Measure dust production in MIR Gordon et al., 2014 Peter Scicluna JCMT Users’ Meeting, Nanjing, 13th February 2017 2 / 9 What about dust destruction? Dust growth in the ISM? Are the masses really correct? The dust budget crisis: locally Measure dust masses in FIR/sub-mm Measure dust production in MIR Done for LMC (Reibel+ 2012), SMC (Srinivasan+2016) Total dust mass ∼ integrated dust production over Hubble time Gordon et al., 2014 Peter Scicluna JCMT Users’ Meeting, Nanjing, 13th February 2017 2 / 9 Dust growth in the ISM? Are the masses really correct? The dust budget crisis: locally Measure dust masses in FIR/sub-mm Measure dust production in MIR Done for LMC (Reibel+ 2012), SMC (Srinivasan+2016) Total dust mass ∼ integrated dust production over Hubble time What about dust destruction? Gordon et al., 2014 Peter Scicluna JCMT Users’ Meeting, Nanjing, 13th February 2017 2 / 9 How important are supernovae? Are there even enough metals yet? Dust growth in the ISM? Are the masses really correct? The dust budget crisis: at high redshift Rowlands et al., 2014 Measure -
Kinetics of Spontaneous Baryogenesis
Kinetics of Spontaneous Baryogenesis Elena Arbuzova Dubna University & Novosibirsk State University based on common work with A.D. Dolgov and V.A. Novikov arXiv:1607.01247 The 10th APCTP-BLTP/JINR-RCNP-RIKEN Joint Workshop on Nuclear and Hadronic Physics Aug. 17 - Aug. 21, 2016, RIKEN, Wako, Japan E. Arbuzova () Kinetics of SBG August 18 1 / 30 Outline Introduction Generalities about SBG Evolution of Baryon Asymmetry Kinetic Equation in Time-dependent Background Conclusions E. Arbuzova () Kinetics of SBG August 18 2 / 30 Standard Cosmological Model (SCM) The Standard Model of Cosmology: the Standard Model of particle physics ) matter content General Relativity ) gravitational interaction the inflationary paradigm ) to fix a few problems of the scenario SCM explains a huge amount of observational data: Hubble's law the primordial abundance of light elements the cosmic microwave background E. Arbuzova () Kinetics of SBG August 18 3 / 30 Some Puzzles Matter Inventory of the Universe: Baryonic matter (mainly protons and neutrons): 5%. Dark matter (weakly interactive particles not belonging to the MSM of particle physics): 25%. Dark energy: 70% of the Universe is really a mystery looking like a uniformly distributed substance with an unusual equation of state P ≈ −%. DE is responsible for the contemporary accelerated expansion of the Universe. The mechanism of inflation still remains at the level of paradigm. It does not fit the framework of the Standard Model of particle physics. Matter-antimatter asymmetry around us: the local Universe is clearly -
Lesson 8 : Baryogenesis
Lesson 8 : Baryogenesis Notes from Prof. Susskind video lectures publicly available on YouTube 1 Introduction Baryogenesis means the creation of matter particles. Its study is more specifically concerned with explaining the excess of matter over antimatter in the universe. The conditions which explain the imbalance of particles and antiparticles are called nowadays the Sakharov conditions 1. In the previous chapter, we studied several landmarks in the temperature of the universe. Going backwads in time, we met the decoupling time when the universe become trans- parent. The temperature was about 4000°. Further back at T ≈ 1010 degrees, photons could create electron-positron pairs. Protons had already been created earlier. Even further back at T ≈ 1012 or 1013, photons could create proton-antiproton pairs. More accurately they could create quark-antiquark pairs, because in truth it was too hot for protons to exist as such. But, at that temperature, let’s say by convention that when we talk about a proton we really talk about three quarks. It does not make any difference in the reasonings. 1. Named after Andrei Sakharov (1921 - 1989), Russian nuclear physicist. Sakharov published his work on this in 1967 in Russian and it remained little known until the 1980s. In the meantime, the same conditions were rediscovered in 1980 by Savas Dimopoulos and Leonard Susskind who were trying to answer the question of why the number of photons, which is a measure of the entropy of the universe, exceeds by eight orders of magnitude the number of protons or electrons. Thus for a time the conditions were known in the West as the Dimopoulos-Susskind conditions. -
Outline of Lecture 2 Baryon Asymmetry of the Universe. What's
Outline of Lecture 2 Baryon asymmetry of the Universe. What’s the problem? Electroweak baryogenesis. Electroweak baryon number violation Electroweak transition What can make electroweak mechanism work? Dark energy Baryon asymmetry of the Universe There is matter and no antimatter in the present Universe. Baryon-to-photon ratio, almost constant in time: nB 10 ηB = 6 10− ≡ nγ · Baryon-to-entropy, constant in time: n /s = 0.9 10 10 B · − What’s the problem? Early Universe (T > 1012 K = 100 MeV): creation and annihilation of quark-antiquark pairs ⇒ n ,n n q q¯ ≈ γ Hence nq nq¯ 9 − 10− nq + nq¯ ∼ How was this excess generated in the course of the cosmological evolution? Sakharov conditions To generate baryon asymmetry, three necessary conditions should be met at the same cosmological epoch: B-violation C-andCP-violation Thermal inequilibrium NB. Reservation: L-violation with B-conservation at T 100 GeV would do as well = Leptogenesis. & ⇒ Can baryon asymmetry be due to electroweak physics? Baryon number is violated in electroweak interactions. Non-perturbative effect Hint: triangle anomaly in baryonic current Bµ : 2 µ 1 gW µνλρ a a ∂ B = 3colors 3generations ε F F µ 3 · · · 32π2 µν λρ ! "Bq a Fµν: SU(2)W field strength; gW : SU(2)W coupling Likewise, each leptonic current (n = e, µ,τ) g2 ∂ Lµ = W ε µνλρFa Fa µ n 32π2 · µν λρ a 1 Large field fluctuations, Fµν ∝ gW− may have g2 Q d3xdt W ε µνλρFa Fa = 0 ≡ 32 2 · µν λρ ' # π Then B B = d3xdt ∂ Bµ =3Q fin− in µ # Likewise L L =Q n, fin− n, in B is violated, B L is not.