Planck Implications for Cosmology

Total Page:16

File Type:pdf, Size:1020Kb

Planck Implications for Cosmology Planck Collaboration: The Planck mission axio Fig. 11. The SMICA CMB map (with 3% of the sky replaced by a constrained Gaussian realization). lensing potential φ(ˆn), as well as estimates of itspower spectrum φWF (ˆn) φφ CL . Although noisy, thePlanck lensing potential map represents a projected measurement of all dark matter back to the last scat- tering surface, with considerable statistical power. InFig. 7.2 we plot the Planck lensing map, and in Fig. 7.2 we show an esti- mate of its signal power spectrum. I have no idea why the fig- urenumbers come out tobe 5.3 no matter what I do... - latex expert needed As a tracer of the large scale gravitational potential, the Planck lensing map issignificantly correlated with other tracers Galactic North Galactic South of large scale structure. We show several representative exam- ples of such correlations in Planck Collaboration XVII (2013), Fig. 14. Wiener-filtered lensing potential estimate reconstruction, in Galactic coordinates using orthographic projection. The reconstruction including the NVSS quasar catalog (Condon et al. 1998), the was bandpass filtered to L ∈ [10, 2048]. Note that the lensing recon- MaxBCG cluster catalog (Koester et al. 2007), luminous red struction, while highly statistically significant, is still noise dominated galaxies from SDSS Ross et al. (2011), and a survey of in- for every individual mode, and isat best S/ N 0.7 around L = 30. frared sources from the WISE satellite (Wright et al. 2010). The strength of the correlation between the Planck lensing map and such tracers provides athfairly direct measure of how they trace (Planck Collaboration XV 2013); here we summarize its main dark matter; from10our measurement Patrasof the lensing Workshop,potential, the features. CERN, 3.07.2014 Planck maps provide a mass survey of the intermediate redshift On large scales, the distribution for the angular power spec- Universe, in addition to a survey of the primary CMB tempera- trum cannot be assumed to be a multivariate Gaussian, and the ture and polarization anisotropies. Galactic contamination is most significant. We use the multi- Julien Lesgourgues (EPFL,frequency temperature CERN,maps from LFI LAPThand HFI, in the) range 7.3. Likelihood code 30 < ν < 353 GHz, to separate Galactic foregrounds. This pro- cedure uses a Gibbs sampling method to estimate the CMB map 7.3.1. CMB likelihood and the probability distribution of its power spectrum, p(C |d), for bandpowers at < 50, using thecleanest 87 % of thesky. We We follow a hybrid approach to construct the likelihood for the supplement this ‘low- ’ temperature likelihood with the pixel- Planck temperature data, using an exact likelihood approach at based polarization likelihood at large-scales ( < 23) from the large scales, < 50, and a pseudo-C power spectrum at smaller WMAP 9-year data release (Bennett et al. 2012). These need to 3.07.2014scales, 50 < < 2500. This follows similarCMB,analyses DM,in, WISPse.g., be corrected& Axionsfor the– J.dust Lesgourguescontamination, for which we use the 1 Spergel et al. (2007). The likelihood is described more fully in WMAP procedure. However, we have checked that switching 24 Planck Collaboration: The Planck mission axio Fig. 11. The SMICA CMB map (with 3% of the sky replaced by a constrained Gaussian realization). lensing potential φ(ˆn), as well as estimates of itspower spectrum φWF (ˆn) φφ CL . Although noisy, thePlanck lensing potential map represents a projected measurement of all dark matter back to the last scat- tering surface, with considerable statistical power. InFig. 7.2 we plot the Planck lensing map, and in Fig. 7.2 we show an esti- mate of its signal power spectrum. I have no idea why the fig- urenumbers come out tobe 5.3 no matter what I do... - latex expert needed As a tracer of the large scale gravitational potential, the Planck lensing map issignificantly correlated with other tracers Galactic North Galactic South of large scale structure. We show several representative exam- ples of such correlations in Planck Collaboration XVII (2013), Fig. 14. Wiener-filtered lensing potential estimate reconstruction, in Galactic coordinates using orthographic projection. The reconstruction including the NVSS quasar catalog (Condon et al. 1998), the was bandpass filtered to L ∈ [10, 2048]. Note that the lensing recon- MaxBCG cluster catalog (Koester et al. 2007), luminous red struction, while highly statistically significant, is still noise dominated Temperature galaxiesspectrumfrom SDSS Ross et al. (2011), and a survey of in- for every individual mode, and isat best S/ N 0.7 around L = 30. frared sources from the WISE satellite (Wright et al. 2010). The strength of the correlation between the Planck lensing map and from Marchsuch 2013tracers provides a fairly direct measure of how they trace (Planck Collaboration XV 2013); here we summarize its main dark matter; from our measurement of the lensing potential, the features. Planck maps provide a mass survey of the intermediate redshift On large scales, the distribution for the angular power spec- Universe, in addition to a survey of the primary CMB tempera- trum cannot be assumed to be a multivariate Gaussian, and the ture and polarization anisotropies. Galactic contamination is most significant. We use the multi- frequency temperature maps from LFI and HFI, in the range 7.3. Likelihood code 30 < ν < 353 GHz, to separate Galactic foregrounds. This pro- cedure uses a Gibbs sampling method to estimate the CMB map 7.3.1. CMB likelihood and the probability distribution of its power spectrum, p(C |d), for bandpowers at < 50, using thecleanest 87 % of thesky. We We follow a hybrid approach to construct the likelihood for the supplement this ‘low- ’ temperature likelihood with the pixel- Planck temperature data, using an exact likelihood approach at based polarization likelihood at large-scales ( < 23) from the large scales, < 50, and a pseudo-C power spectrum at smaller WMAP 9-year data release (Bennett et al. 2012). These need to 3.07.2014scales, 50 < < 2500. This follows similarCMB,analyses DM,in, WISPse.g., be corrected& Axionsfor the– J.dust Lesgourguescontamination, for which we use the 2 Spergel et al. (2007). The likelihood is described more fully in WMAP procedure. However, we have checked that switching 24 Planck Collaboration: Gravitational lensing by large-scale structures with Planck maps). To match the power spectrum of these simulations to the Power spectrum estimates at this mask level show consis- power spectrum of the data maps, we find it isnecessary to add tency with the MV reconstruction within two standard devia- extragalactic foreground power following the model in Sect. 4, tions of the measurement uncertainty. The increased sky cover- 2 2 with Acib = 18 µK and Asrc = 28 µK . The resulting simula- age does not bring significant improvements in the error-bars of tions have a power spectrum which agrees with that of the CMB thepower spectrum, however. Using Eq. 20 as an estimate of the map estimate based on the data to better than 2% at l < 2048. power spectrum variance, the larger sky coverage yields only a This could be improved slightly by tailoring a specific correc- 3.5% improvement at L < 40 over the MV result, decreasing tion for each map. We also add homogeneous pixel noise with a down to 0 at L = 400. This could be due to the different weight- Planck Collaboration: The Planck mission level of 12 µK arcmin. If we neglected this power, theagreement ing used in the component separation compared to the one of would be only at the 8% level, primarily due to the noise term the MV map, which results in slightly noisier maps for our pur- (the Acib and Asrc contributions are each at the level of 1 − 2%). pose. While the component separated maps allow for a reduced Due to the procedure which we use to subtract the disconnected mask maintaining arobust lensing potential estimation, they lead noise bias (Eq. 17) from our lensing power spectrum estimates, to a marginal improvement of the power spectrum uncertainties. the inclusion of these components does not significantly affect Nevertheless, their agreement with the MV result isreassuring. our results, but comparison with the values used for our single- frequency simulations in Sect. 4 are a useful indicator of the ex- tent to which the foreground separation algorithms are able to remove extragalactic foreground power in the high- regime. As already discussed, our results on the component- separated CMB maps are presented in Fig. 18. Because the CMB and FFP6 noise components of the foreground-cleaned map simulations are the same as those used to characterize our fiducial lens reconstruction, we can measure the expected scatter between the foreground separated maps and our fidu- cial reconstruction. This scatter will be slightly overestimated because we have not attempted to coherently model the con- tribution to the reconstruction noise from residual diffuse eaxiox- MV, fsky = 0.70 tragalactic foreground power. For the eight bins in 40 ≤ L ≤ 400 on which ourFig. 11.fiducialThe SMICAlikCMBelihoodmap (withis3%based,of the skywereplacedmeasureby a constraineda Gaussian realization). χ2 for the difference between our fiducial reconstruction and 2 the correspondinglensingforepotentialground-cleanedφ(ˆn), as well as estimatesreconstructionof itspower spectrumof χ =φWF (ˆn) φφ (3.14, 4.3, 2.5, 14C.7)L . Althoughfor nilnoisy c, smica, thePlanc, sevemk lensing, potentialand r mapul errepresentsrespec- 2a projected measurement of all dark matter back to the last scat- tively. These
Recommended publications
  • Naturally Light Sterile Neutrinos in Gauge Mediated Supersymmetry
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server hep-ph/9810257 IC/98/163 WIS-98/25/Oct-DPP Naturally Light Sterile Neutrinos in Gauge Mediated Sup ersymmetry Breaking a b Gia Dvali and Yosef Nir a ICTP, Trieste, 34100, Italy b Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100, Israel Mo duli are generic in string (M) theory. In a large class of gauge-mediated Sup ersymmetry breaking mo dels, the fermionic comp onents of such elds havevery light masses, around the eV scale, and non-negligible mixing with 4 active neutrinos, of order 10 . Consequently, these fermions could play the role of sterile neutrinos to which active neutrinos oscillate, thus a ecting measurements of solar neutrinos or of atmospheric neutrinos. They could also provide warm dark matter, thus a ecting structure formation. 10/98 1. Intro duction Light sterile neutrinos are o ccasionally invoked by theorists to explain various hints of neutrino masses which cannot b e accommo dated in a framework of only three light active neutrinos (see e.g. refs. [1-26]). There are, however, three puzzles related to the hyp othesis that light sterile neutrinos may play a role in various observations: (i) The Ma jorana mass term of a sterile neutrino is not protected byany Standard Mo del (SM) gauge symmetry and can, therefore, be arbitrarily large. The mass that is relevant to the various exp eriments is at or b elow the eV scale. (ii) The Dirac mass term that mixes a sterile neutrino with an active one is protected by the electroweak breaking scale and is exp ected to b e in the range m m .
    [Show full text]
  • Phenomenology of Gev-Scale Heavy Neutral Leptons Arxiv:1805.08567
    Prepared for submission to JHEP INR-TH-2018-014 Phenomenology of GeV-scale Heavy Neutral Leptons Kyrylo Bondarenko,1 Alexey Boyarsky,1 Dmitry Gorbunov,2;3 Oleg Ruchayskiy4 1Intituut-Lorentz, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands 2Institute for Nuclear Research of the Russian Academy of Sciences, Moscow 117312, Russia 3Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia 4Discovery Center, Niels Bohr Institute, Copenhagen University, Blegdamsvej 17, DK- 2100 Copenhagen, Denmark E-mail: [email protected], [email protected], [email protected], [email protected] Abstract: We review and revise phenomenology of the GeV-scale heavy neutral leptons (HNLs). We extend the previous analyses by including more channels of HNLs production and decay and provide with more refined treatment, including QCD corrections for the HNLs of masses (1) GeV. We summarize the relevance O of individual production and decay channels for different masses, resolving a few discrepancies in the literature. Our final results are directly suitable for sensitivity studies of particle physics experiments (ranging from proton beam-dump to the LHC) aiming at searches for heavy neutral leptons. arXiv:1805.08567v3 [hep-ph] 9 Nov 2018 ArXiv ePrint: 1805.08567 Contents 1 Introduction: heavy neutral leptons1 1.1 General introduction to heavy neutral leptons2 2 HNL production in proton fixed target experiments3 2.1 Production from hadrons3 2.1.1 Production from light unflavored and strange mesons5 2.1.2
    [Show full text]
  • Arxiv:1801.08947V2 [Hep-Ph] 24 May 2018
    UCI-TR-2017-18 Heavy Neutral Leptons at FASER Felix Kling1, ∗ and Sebastian Trojanowski1, 2, y 1Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575 USA 2National Centre for Nuclear Research, Ho_za 69, 00-681 Warsaw, Poland Abstract We study the prospects for discovering heavy neutral leptons at ForwArd Search ExpeRiment, or FASER, the newly proposed detector at the LHC. Previous studies showed that a relatively small 2 detector with ∼ 10 m length and . 1 m cross sectional area can probe large unconstrained parts of parameter space for dark photons and dark Higgs bosons. In this work we show that FASER will also be sensitive to heavy neutral leptons that have mixing angles with the active neutrinos that are up to an order of magnitude lower than current bounds. In particular, this is true for heavy neutral leptons produced dominantly in B-meson decays, in which case FASER's discovery potential is comparable to the proposed SHiP detector. We also illustrate how the search for heavy neutral leptons at FASER will be complementary to ongoing searches in high-pT experiments at the LHC and can shed light on the nature of dark matter and the process of baryogenesis in the early Universe. arXiv:1801.08947v2 [hep-ph] 24 May 2018 ∗Electronic address: [email protected] yElectronic address: [email protected] 1 I. INTRODUCTION In the past years, the Large Hadron Collider (LHC) has collected an impressive amount of data and placed constraints on a multitude of models for new physics. Most of these searches are targeting high-pT signatures corresponding to new strongly interacting heavy particles.
    [Show full text]
  • Topics in Physics Beyond the Standard Model Phd Thesis
    Topics in Physics Beyond the Standard Model PhD Thesis Andrea Caputo IFIC - Universitat de València - CSIC Departamento de Física Teórica Programa de Doctorado en Física Under the supervision of Pilar Hernandez Gamazo Valencia, Julio 2020 Pilar Hernández Gamazo, catedrática del Departamento de Física Teórica de la Universidad de Valencia, Certifica: Que la presente memoria, ”Topics in physics Beyond The Standard Model” ,ha sido realizada bajo su dirección en el Instituto de Física Corpuscular, centro mixto de la Universidad de Valencia y del CSIC, por Andrea Caputo, y constituye su Tesis para optar al grado de Doctor en Ciencias Físicas. Y para que así conste, en cumplimiento de la legislación vigente, presenta en el Departamento de Física Teórica de la Universidad de Valencia la referida Tesis Doctoral, y firman el presente certificado. Valencia, Julio 2020 Pilar Hernández Gamazo List of Publications This PhD thesis is based on the following publications: • The seesaw path to leptonic CP violation [1] Caputo, A. and Hernandez, P. and Kekic, M. and Lopez-Pavon, J. and Salvado, J. Eur. Phys. J. C77 (2017) no.4, 258,[1611.05000]. • The seesaw portal in testable models of neutrino masses [2] Caputo, A. and Hernandez,P. and Lopez-Pavon, J. and Salvado, J. JHEP 1706 (2017) 112,[1704.08721]. • Looking for Axion Dark Matter in Dwarf Spheroidals [3] Caputo, A. and Garay, C. P and Witte, S.J. Phys.Rev. D 98 (2018) no.8, 083024,[1805.08780]. • Leptogenesis from oscillations and dark matter [4] Caputo, A. and Hernandez, P. and Rius, N. Eur.Phys.J. C 79 (2019) no.7, 574,[1807.03309].
    [Show full text]
  • Impact of Sterile Neutrinos in Lepton Flavour Violating Processes
    Valentina De Romeri UAM/IFT Madrid Impact of sterile neutrinos in lepton flavour violating processes based on JHEP 1504 (2015) 051 and JHEP 1602 (2016) 083 done in collaboration with Asmaa Abada2 and Ana Teixeira1 1) Laboratoire de Physique Corpusculaire Clermont-Ferrand 2) Laboratoire de Physique Theorique, Orsay 1 Valentina De Romeri - UAM/IFT Madrid Lepton flavour violation and new physics ‣ By construction, lepton flavour violation (LFV) is forbidden in the SM (Strict conservation of total lepton number (L) and lepton flavours (Li))" ! !BUT … neutral lepton flavour is violated through neutrino oscillations! (solar, atmospheric, reactor neutrino data)" ! !Flavour violation in the charged lepton sector: NEW PHYSICS beyond SMm# (SM with UPMNS)!" ! !Are neutral and charged LFV (cLFV) related?$ Does cLFV arise from #-mass mechanism? " ! !We will focus on the study of cLFV signals arising in minimal extensions of the SM by sterile fermion states 2 Valentina De Romeri - UAM/IFT Madrid Beyond the 3-neutrino paradigm: Sterile neutrinos ! From the invisible decay width of the Z boson [LEP]:" ⇒ extra neutrinos must be sterile (=EW singlets) or cannot be a Z decay product" Any singlet fermion that mixes with the SM neutrinos" ● Right-handed neutrinos ● Other singlet fermions" ! !Sterile neutrinos are SM gauge singlets - colourless, no weak interactions, electrically neutral. Interactions with SM fields: through mixings with active neutrinos (via Higgs)" !No bound on the number of sterile states, no limit on their mass scale(s)" !Phenomenological interest (dependent on the mass scale): 3 Valentina De Romeri - UAM/IFT Madrid Beyond the 3-neutrino paradigm: Sterile neutrinos ! From the invisible decay width of the Z boson [LEP]:" ⇒ extra neutrinos must be sterile (=EW singlets) or cannot be a Z decay product" Any singlet fermion that mixes with the SM neutrinos" ● Right-handed neutrinos ● Other singlet fermions" ! !Sterile neutrinos are SM gauge singlets - colourless, no weak interactions, electrically neutral.
    [Show full text]
  • 27. Dark Matter
    1 27. Dark Matter 27. Dark Matter Written August 2019 by L. Baudis (Zurich U.) and S. Profumo (UC Santa Cruz). 27.1 The case for dark matter Modern cosmological models invariably include an electromagnetically close-to-neutral, non- baryonic matter species with negligible velocity from the standpoint of structure formation, gener- ically referred to as “cold dark matter” (CDM; see The Big-Bang Cosmology—Sec. 22 of this Re- view). For the benchmark ΛCDM cosmology adopted in the Cosmological Parameters—Sec. 25.1 of this Review, the DM accounts for 26.4% of the critical density in the universe, or 84.4% of the total matter density. The nature of only a small fraction, between at least 0.5% (given neutrino os- cillations) and at most 1.6% (from combined cosmological constraints), of the non-baryonic matter content of the universe is known: the three Standard Model neutrinos (see the Neutrino Masses, Mixing, and Oscillations—Sec. 14 of this Review) ). The fundamental makeup of the large majority of the DM is, as of yet, unknown. Assuming the validity of General Relativity, DM is observed to be ubiquitous in gravitation- ally collapsed structures of size ranging from the smallest known galaxies [1] to galaxies of size comparable to the Milky Way [2], to groups and clusters of galaxies [3]. The mass-to-light ratio is observed to saturate at the largest collapsed scales to a value indicative, and close to, what inferred from other cosmological observations for the universe as a whole [4]. In such collapsed structures, the existence of DM is inferred directly using tracers of mass enclosed within a certain radius such as stellar velocity dispersion, rotation curves in axisymmetric systems, the virial theorem, gravitational lensing, and measures of the amount of non-dark, i.e.
    [Show full text]
  • 2 Particle Dynamics in an Expanding Universe 5 2.1 the Friedmann Equations
    European Research Universität Hamburg Council DER FORSCHUNG I DER LEHRE | DER BILDUNG PRIMORDIAL NUCLEOSYNTHESIS IN THE PRESENCE OF MEV-SCALE DARK SECTORS Dissertation zur Erlangung des Doktorgrades an der Fakultät für Mathematik, Informatik und Naturwissenschaften Fachbereich Physik der Universitat Hamburg vorgelegt von Marco Hufnagel aus Hamburg 2020 Gutachter der Dissertation: Dr. Kai Schmidt-Hoberg Prof. Dr. Geraldine Servant Zusammensetzung der Prüfungskommission: Dr. Kai Schmidt-Hoberg Prof. Dr. Geraldine Servant Prof. Dr. Jochen Liske Prof. Dr. Gudrid Moortgat-Pick Dr. Torben Ferber Vorsitzender der Prüfungskommission: Prof. Dr. Jochen Liske Datum der Disputation: 15.06.2020 Vorsitzender des Fach-Promotionsausschusses PHYSIK: Prof. Dr. Günter H. W. Sigl Leiter des Fachbereichs PHYSIK: Prof. Dr. Wolfgang Hansen Dekan der Fakultät MIN: Prof. Dr. Heinrich Graener “Come on, Rory! It isn't rocket science, it's just quantum physics!” - The Doctor “This is not the time for vanity. It's the time to show the universe how amazingly awesome I am!” - Captain Qwark Dedicated to all the equations I have solved before. i Abstract In this thesis, we perform a comprehensive study of Big Bang nucleosynthesis constraints on different dark-sector models with MeV-scale particles which are neither fully relativistic nor fully non-relativistic during all relevant temperatures. To this end, we derive a generic set of equations that can be used to determine the light-element abundances for many different dark-sector scenarios. In particular, we take into account all relevant effects that might alter the creation of light elements in the early universe, including modifications to the Hubble rate and time-temperature relation, an adjusted best-fit value for the baryon-to-photon ratio due to an altered effective number of neutrinos, a modified neutrino-decoupling temperature as well as late-time modifications of the nuclear abundances due to photodisintegration.
    [Show full text]
  • Jhep03(2021)148
    Published for SISSA by Springer Received: November 13, 2020 Accepted: January 29, 2021 Published: March 15, 2021 Long-lived sterile neutrinos at the LHC in effective field theory JHEP03(2021)148 Jordy de Vries,a;b Herbert K. Dreiner,c Julian Y. G¨unther,c Zeren Simon Wangd;e and Guanghui Zhoua aAmherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts, Amherst, MA 01003, U.S.A. bRIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.A. cBethe Center for Theoretical Physics & Physikalisches Institut der Universit¨atBonn, Nußallee 12, 53115 Bonn, Germany dDepartment of Physics, National Tsing Hua University, Hsinchu 300, Taiwan eAsia Pacific Center for Theoretical Physics (APCTP), Headquarters San 31, Hyoja-dong, Nam-gu, Pohang 790-784, South Korea E-mail: [email protected], [email protected], [email protected], [email protected], [email protected] Abstract: We study the prospects of a displaced-vertex search of sterile neutrinos at the Large Hadron Collider (LHC) in the framework of the neutrino-extended Standard Model Effective Field Theory (νSMEFT). The production and decay of sterile neutrinos can proceed via the standard active-sterile neutrino mixing in the weak current, as well as through higher-dimensional operators arising from decoupled new physics. If sterile neu- trinos are long-lived, their decay can lead to displaced vertices which can be reconstructed. We investigate the search sensitivities for the ATLAS/CMS detector, the future far-detector experiments: AL3X, ANUBIS, CODEX-b, FASER, MATHUSLA, and MoEDAL-MAPP, and at the proposed fixed-target experiment SHiP.
    [Show full text]
  • Sterile Neutrino
    Right-handed sneutrino as cold dark matter of the universe Takehiko Asaka (EPFL Æ Niigata University) @ TAUP2007 (11/09/2007, Sendai) Refs: with Ishiwata and Moroi Phys.Rev.D73:061301,2006 Phys.Rev.D75:065001,2007 I. Introduction Dark Matter Content of the universe [WMAP ’06] Dark energy (74%) Baryon (4%) Dark matter (22%) What is dark matter??? z No candidate in SM ⇒ New Physics !!! z One attractive candidate LSP in supersymmetric theories LSP Dark Matter R-parity: ordinary SM particles: R-parity even (+1) additional superparticles: R-parity odd (-1) z Lightest superparticle (LSP) is stable z LSP is a good candidate of DM if it is neutral What is the LSP DM? z Lightest neutralino (= combination of neutral gauginos and higgsinos) Other candidates for LSP DM The lightest neutralino is NOT the unique candidate for the LSP DM z In supergravity, “gravitino” z In superstring, “modulino” z With Peccei-Quinn symmetry, “axino” z … Now, we know that the MSSM is incomplete accounting for neutrino oscillations Æ alternative candidate for the LSP DM In this talk, Introduce RH neutrinos to explain neutrino masses z In supersymmetric theories, RH neutrino + RH sneutrino fermion (Rp=+1) scalar (Rp=-1) If neutrino masses are purely Dirac-type, z Masses of RH sneutrinos come from SUSY breaking — z Lightest RH sneutrino can be LSP, z LSP RH sneutrino is a good candidate for CDM (i.e., can be realized) II. Right-handed sneutrino as dark matter Model MSSM + three right-handed (s)neutrinos assuming neutrino masses are purely Dirac-type z Yukawa couplings are very small z Small Yukawa couplings are natural in ‘tHooft’s sense — chiral symmetry of neutrinos is restored in the limit of vanishing Yukawa couplings Model (2) LSP = z only suppressed interaction: NLSP = MSSM-LSP z MSSM-LSP can be charged z rather long-lived: —typically Our claim: LSP as CDM How are produced in the early universe??? Production of RH sneutrino is not thermalized in the early universe!!! z Interaction rate of is very small: — Typically, How are produced in the early universe??? A.
    [Show full text]
  • Impact of Sterile Neutrinos in Lepton Flavour Violating Processes
    XIV International Conference on Topics in Astroparticle and Underground Physics (TAUP 2015) IOP Publishing Journal of Physics: Conference Series 718 (2016) 062013 doi:10.1088/1742-6596/718/6/062013 IFT-UAM/CSIC-15-131 Impact of sterile neutrinos in lepton flavour violating processes Valentina De Romeri1 Instituto de F´ısicaTe´oricaUAM/CSIC, Calle Nicol´asCabrera 13-15, Cantoblanco E-28049 Madrid, Spain E-mail: [email protected] Abstract. We discuss charged lepton flavour violating processes occurring in minimal extensions of the Standard Model via the addition of sterile fermions. We firstly investigate the possibility of their indirect detection at a future high-luminosity Z-factory (such as FCC- ∓ ± ee). Rare decays such as Z ! `1 `2 can indeed be complementary to low-energy (high-intensity) observables of lepton flavour violation. We further consider a sterile neutrino-induced charged lepton flavour violating process occurring in the presence of muonic atoms: their (Coulomb enhanced) decay into a pair of electrons µ−e− ! e−e−. Our study reveals that, depending on their mass range and on the active-sterile mixing angles, sterile neutrinos can give significant contributions to the above mentioned observables, some of them even lying within present and future sensitivity of dedicated cLFV experiments and of FCC-ee. 1. Introduction Several extensions of the Standard Model (SM) add sterile neutrinos to the particle content in order to account for neutrino masses and mixings. These models are further motivated by anomalous (oscillation) experimental results, as well as by certain indications from cosmology (see [1, 2] and references therein). The existence of these sterile states may be investigated in many fronts, among them at high-energy colliders.
    [Show full text]
  • Sterile Neutrinos Arxiv:2106.05913V1 [Hep-Ph] 10 Jun 2021
    Sterile Neutrinos Basudeb Dasgupta Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai, 400005, India. [email protected] Joachim Kopp Theoretical Physics Department, CERN, Geneva, Switzerland and Johannes Gutenberg University Mainz, 55099 Mainz, Germany [email protected] June 11, 2021 arXiv:2106.05913v1 [hep-ph] 10 Jun 2021 Neutrinos, being the only fermions in the Standard Model of Particle Physics that do not possess electromagnetic or color charges, have the unique opportunity to communicate with fermions outside the Standard Model through mass mixing. Such Standard Model- singlet fermions are generally referred to as “sterile neutrinos”. In this review article, we discuss the theoretical and experimental motivation for sterile neutrinos, as well as their phenomenological consequences. With the benefit of hindsight in 2020, we point out potentially viable and interesting ideas. We focus in particular on sterile neutrinos that are light enough to participate in neutrino oscillations, but we also comment on the benefits of introducing heavier sterile states. We discuss the phenomenology of eV- scale sterile neutrinos in terrestrial experiments and in cosmology, we survey the global data, and we highlight various intriguing anomalies. We also expose the severe tension that exists between different data sets and prevents a consistent interpretation of the global data in at least the simplest sterile neutrino models. We discuss non-minimal scenarios that may alleviate some of this tension. We briefly review the status of keV-scale sterile neutrinos as dark matter and the possibility of explaining the matter–antimatter asymmetry of the Universe through leptogenesis driven by yet heavier sterile neutrinos.
    [Show full text]
  • The Sterile Neutrino
    EPJ Web of Conferences 207, 04004 (2019) https://doi.org/10.1051/epjconf/201920704004 VLVnT-2018 The Sterile Neutrino A short introduction 1, Dmitry V. Naumov ∗ 1Joint Institute for Nuclear Research Abstract. This is a pedagogical introduction to the main concepts of the sterile neutrino - a hypothetical particle, coined to resolve some anomalies in neu- trino data and retain consistency with observed widths of the W and Z bosons. We briefly review existing anomalies and the oscillation parameters that best describe these data. We discuss in more detail how sterile neutrinos can be ob- served, as well as the consequences of its possible existence. In particular, we pay attention to a possible loss of coherence in a model of neutrino oscillations with sterile neutrinos, where this effect might be of a major importance with re- spect to the 3ν model. The current status of searches for a sterile neutrino state is also briefly reviewed. 1 Introduction There are three generations of leptons in the Standard Model (SM) ν ν ν 1 , 2 , 3 (1) e µ τ L L L grouped into three SU(2)L doublets. The sub-index L indicates that the quantum fields νi (i = 1, 2, 3) and (α = e, µ, τ) are eigenstates of the P = 1 (1 γ ) left-handed helicity α L 2 − 5 operator. The SM also contains the right-handed fields of leptons as SU(2)L singlets. These 1 fields are eigenstates of PR = 2 (1 + γ5). The fields νi and α have definite masses and they obey the Dirac equation.
    [Show full text]