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Sample records for axion racing team

  1. China's Shineray Racing Team Hits International Circuit

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ China Shineray International Motocross Racing Team is Chongqing Shineray Group's international racing team, established in March 2004. in less than two years, this team has developed into the representative of numerous Chinese enterprises.

  2. The Axion Dark Matter Experiment: Big Science with a (relatively) Small Team

    Science.gov (United States)

    Carosi, Gianpaolo

    2016-03-01

    The idea of the solitary physicist tinkering alone in a lab was my image of how science was done growing up (mostly influenced by popular culture). Of course this is not generally how experimental physics is done now days with examples of experiments at the LHC now involving thousands of scientists. In this talk I will describe my experience in a relatively modest project, the Axion Dark Matter eXperiment (ADMX), which involves only a few dozen scientists at various universities and national labs. I will outline ADMX's humble beginnings at Lawrence Livermore National Laboratory (LLNL), where it began in the mid-1990s, and describe how the collaboration has evolved and grown throughout the years, as we pursue our elusive quarry: the dark-matter axion. Supported by DOE Grants DE-FG02-97ER41029, DE-FG02-96ER40956, DE- AC52-07NA27344, DE-AC03-76SF00098, and the Livermore LDRD program.

  3. Axion Bremsstrahlung

    CERN Document Server

    Melkumova, E Y; Kerner, R; Melkumova, Elena; Tsov, Dmitry V. Gal'; Kerner, Richard

    2003-01-01

    A new mechanism of cosmic axion production is proposed: axion bremsstrahlung from collisions of straight global strings. This effect is of the second order in the axion coupling constant, but the resulting cosmological estimate is likely to be of the same order as that corresponding to radiation from oscillating string loops. This may lead to a further restriction on the axion window.

  4. Axion cosmology

    Science.gov (United States)

    Marsh, David J. E.

    2016-07-01

    Axions comprise a broad class of particles that can play a major role in explaining the unknown aspects of cosmology. They are also well-motivated within high energy physics, appearing in theories related to CP-violation in the standard model, supersymmetric theories, and theories with extra-dimensions, including string theory, and so axion cosmology offers us a unique view onto these theories. I review the motivation and models for axions in particle physics and string theory. I then present a comprehensive and pedagogical view on the cosmology and astrophysics of axion-like particles, starting from inflation and progressing via BBN, the CMB, reionization and structure formation, up to the present-day Universe. Topics covered include: axion dark matter (DM); direct and indirect detection of axions, reviewing existing and future experiments; axions as dark radiation; axions and the cosmological constant problem; decays of heavy axions; axions and stellar astrophysics; black hole superradiance; axions and astrophysical magnetic fields; axion inflation, and axion DM as an indirect probe of inflation. A major focus is on the population of ultralight axions created via vacuum realignment, and its role as a DM candidate with distinctive phenomenology. Cosmological observations place robust constraints on the axion mass and relic density in this scenario, and I review where such constraints come from. I next cover aspects of galaxy formation with axion DM, and ways this can be used to further search for evidence of axions. An absolute lower bound on DM particle mass is established. It is ma > 10-24eV from linear observables, extending to ma ≳ 10-22eV from non-linear observables, and has the potential to reach ma ≳ 10-18eV in the future. These bounds are weaker if the axion is not all of the DM, giving rise to limits on the relic density at low mass. This leads to the exciting possibility that the effects of axion DM on structure formation could one day be detected

  5. Domestic Axion

    CERN Document Server

    Dvali, Gia

    2016-01-01

    We attempt to identify a phenomenologically viable solution to the strong $CP$ problem in which the axion is composed entirely out of Standard Model fermion species. The axion consists predominantly of the $\\eta'$ meson with a minuscule admixture of a pseudoscalar bilinear composite of neutrinos, $\\eta_{\

  6. Axion Cosmology

    CERN Document Server

    Marsh, David J E

    2015-01-01

    Axions comprise a broad class of particles that can play a major role in explaining the unknown aspects of cosmology. They are also extraordinarily well-motivated within high energy physics, and so axion cosmology offers us a unique view onto these theories. I present a comprehensive and pedagogical view on the cosmology and astrophysics of axion-like particles, starting from inflation and progressing via the CMB and structure formation up to the present-day Universe. I briefly review the motivation and models for axions in particle physics and string theory. The primary focus is on the population of ultralight axions created via vacuum realignment, and its role as a dark matter (DM) candidate with distinctive phenomenology. Cosmological observations place robust constraints on the axion mass and relic density in this scenario, and I review where such constraints come from. I next cover aspects of galaxy formation with axion DM, and ways this can be used to further search for evidence of axions. An absolute l...

  7. Nutritional behavior of cyclists during a 24-hour team relay race: a field study report

    Directory of Open Access Journals (Sweden)

    Bescós Raúl

    2012-02-01

    Full Text Available Abstract Background Information about behavior of energy intake in ultra-endurance cyclists during a 24-hour team relay race is scarce. The nutritional strategy during such an event is an important factor which athletes should plan carefully before the race. The purpose of this study was to examine and compare the nutritional intake of ultra-endurance cyclists during a 24-hour team relay race with the current nutritional guidelines for endurance events. Additionally, we analyzed the relationship among the nutritional and performance variables. Methods Using a observational design, nutritional intake of eight males (mean ± SD: 36.7 ± 4.7 years; 71.6 ± 4.9 kg; 174.6 ± 7.3 cm; BMI 23.5 ± 0.5 kg/m2 participating in a 24-hour team relay cycling race was assessed. All food and fluid intake by athletes were weighed and recorded. Additionally, distance and speed performed by each rider were also recorded. Furthermore, before to the race, all subjects carried out an incremental exercise test to determine two heart rate-VO2 regression equations which were used to estimate the energy expenditure. Results The mean ingestion of macronutrients during the event was 943 ± 245 g (13.1 ± 4.0 g/kg of carbohydrates, 174 ± 146 g (2.4 ± 1.9 g/kg of proteins and 107 ± 56 g (1.5 ± 0.7 g/kg of lipids, respectively. This amount of nutrients reported an average nutrient intake of 22.8 ± 8.9 MJ which were significantly lower compared with energy expenditure 42.9 ± 6.8 MJ (P = 0.012. Average fluid consumption corresponded to 10497 ± 2654 mL. Mean caffeine ingestion was 142 ± 76 mg. Additionally, there was no relationship between the main nutritional variables (i.e. energy intake, carbohydrates, proteins, fluids and caffeine ingestion and the main performance variables (i.e. distance and speed. Conclusions A 24-hour hours cycling competition in a team relay format elicited high energy demands which were not compensated by energy intake of the athletes despite

  8. Axion Mediation

    CERN Document Server

    Baryakhtar, Masha; March-Russell, John

    2013-01-01

    We explore the possibility that supersymmetry breaking is mediated to the Standard Model sector through the interactions of a generalized axion multiplet that gains a F-term expectation value. Using an effective field theory framework we enumerate the most general possible set of axion couplings and compute the Standard Model sector soft-supersymmetry-breaking terms. Unusual, non-minimal spectra, such as those of both natural and split supersymmetry are easily implemented. We discuss example models and low-energy spectra, as well as implications of the particularly minimal case of mediation via the QCD axion multiplet. We argue that if the Peccei-Quinn solution to the strong-CP problem is realized in string theory then such axion-mediation is generic, while in a field theory model it is a natural possibility in both DFSZ- and KSVZ-like regimes. Axion mediation can parametrically dominate gravity-mediation and is also cosmologically beneficial as the constraints arising from axino and gravitino overproduction ...

  9. Is Heavy Quark Axion Necessarily Hadronic Axion?

    OpenAIRE

    Chang, Sanghyeon; Kim, Jihn E.

    1993-01-01

    We show that heavy quark axion is not necessarily a hadronic axion, which manifests in the quark and lepton seesaw mechanism. We introduce a heavy $SU(2)$ singlet fermion for each known fermion in order to unify the axion scale and the seesaw scale. The light quarks and leptons gain their masses by the seesaw mechanism. Even though our axion model gives a kind of heavy quark axion, the axion has tree level lepton--axion coupling suppressed by $F_a$, contrary to a widely known belief that heav...

  10. Axion Crystals

    CERN Document Server

    Ozaki, Sho

    2016-01-01

    The low-energy effective theories for gapped insulators are classified by three parameters: permittivity $\\epsilon$, permeability $\\mu$, and theta angle $\\theta$. Crystals with periodic $\\epsilon$ are known as photonic crystals. We here study the band structure of photons in a new type of crystals with periodic $\\theta$ (modulo $2\\pi$) in space, which we call the axion crystals. We find that the axion crystals have a number of new properties that the usual photonic crystals do not possess, such as the helicity-dependent photonic band gaps and the nonrelativistic gapless dispersion relation at small momentum. We briefly discuss possible realizations of axion crystals in condensed matter systems as well as high-energy physics.

  11. Axions : Theory and Cosmological Role

    OpenAIRE

    Kawasaki, Masahiro; Nakayama, Kazunori

    2013-01-01

    We review recent developments on axion cosmology. Topics include : axion cold dark matter, axions from topological defects, axion isocurvature perturbation and its non-Gaussianity and axino/saxion cosmology in supersymmetric axion model.

  12. Axions and SN 1987A: Axion trapping

    Science.gov (United States)

    Burrows, Adam; Ressell, M. Ted; Turner, Michael S.

    1990-01-01

    If an axion of mass between about 10(exp -3) and 10 eV exists, axion emission would have significantly affected the cooling of the nascent neutron star associated with SN 1987A. For an axion of mass greater than about 10(exp -2) eV axions would, like neutrinos, have a mean-free path that is smaller than the size of a neutron star, and thus would become trapped and radiated from an axion sphere. The trapping regime is treated by using numerical models of the initial cooling of a hot neutron star that incorporate a diffusion approximation for axion-energy transport. The axion opacity due to inverse nucleon-nucleon, axion bremsstrahlung is computed; and then the numerical models are used to calculate the integrated axion luminosity, the temperature of the axion sphere, and the effect of axion emission on the neutrino bursts detected by the Kamiokande II (KII) and Irvine-Michigan-Brookhaven (IMB) water-Cherenkov detectors. The larger the axion mass, the stronger the trapping and the smaller the axion luminosity. The estimate of the axion mass is confirmed above which trapping is so strong that axion emission does not significantly affect the neutrino burst. Based upon the neutrino-burst duration - the most sensitive barometer of axion cooling - it is concluded that for an axion mass greater than about 3 eV axion emission would not have had a significant effect on the neutrino bursts detected by KII and IMB. It is strongly suggested that an axion with mass in the interval 10(exp -3) to 3 eV is excluded by the observation of neutrinos from SN 1987A.

  13. Thermal axion production

    OpenAIRE

    Salvio, Alberto; Strumia, Alessandro; Xue, Wei

    2014-01-01

    We reconsider thermal production of axions in the early universe, including axion couplings to all Standard Model (SM>) particles. Concerning the axion coupling to gluons, we find that thermal effects enhance the axion production rate by a factor of few with respect to previous computations performed in the limit of small strong gauge coupling. Furthermore, we find that the top Yukawa coupling induces a much larger axion production rate, unless the axion couples to SM particles only via anom...

  14. Emission of Photons and Relativistic Axions from Axion Stars

    CERN Document Server

    Braaten, Eric; Zhang, Hong

    2016-01-01

    The number of nonrelativistic axions can be changed by inelastic reactions that produce photons or relativistic axions. Any odd number of axions can annihilate into two photons. Any even number of nonrelativistic axions can scatter into two relativistic axions. We calculate the rate at which axions are lost from axion stars from these inelastic reactions. In dilute systems of axions, the dominant inelastic reaction is axion decay into two photons. In sufficiently dense systems of axions, the dominant inelastic reaction is the scattering of four nonrelativistic axions into two relativistic axions. The scattering of odd numbers of axions into two photons produces monochromatic radio-frequency signals at odd-integer harmonics of the fundamental frequency set by the axion mass. This provides a unique signature for dense systems of axions, such as a dense axion star or a collapsing dilute axion star.

  15. Axions at the International Axion Observatory

    CERN Document Server

    Redondo, Javier

    2016-01-01

    QCD axions with meV mass can be behind some stellar cooling anomalies and form all or part of the cold dark matter of the universe. We discuss on a proposed experiment to discover the solar flux of meV mass axions: the International AXion Observatory: IAXO.

  16. Experimental probes of axions

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Aaron S.; /Fermilab

    2009-10-01

    Experimental searches for axions or axion-like particles rely on semiclassical phenomena resulting from the postulated coupling of the axion to two photons. Sensitive probes of the extremely small coupling constant can be made by exploiting familiar, coherent electromagnetic laboratory techniques, including resonant enhancement of transitions using microwave and optical cavities, Bragg scattering, and coherent photon-axion oscillations. The axion beam may either be astrophysical in origin as in the case of dark matter axion searches and solar axion searches, or created in the laboratory from laser interactions with magnetic fields. This note is meant to be a sampling of recent experimental results.

  17. Dark Axion Portal

    OpenAIRE

    Kaneta, Kunio; Lee, Hye-Sung(Theory Division, CERN, CH-1211, Geneva 23, Switzerland); Yun, Seokhoon

    2016-01-01

    The dark photon and the axion (or axion-like particle) are among the popular light particles of the hidden sector. Each of them has been actively searched for through the couplings called the vector portal and the axion portal. We introduce a new portal connecting the dark photon and the axion (axion-photon-dark photon, axion-dark photon-dark photon), which emerges in the presence of the two particles. This dark axion portal is genuinely new couplings, not just from a product of the vector po...

  18. Axions from 1987A

    Science.gov (United States)

    Turner, Michael S.

    1988-01-01

    The process of axion emission from SN 1987A by nucleon-nucleon axion bremsstrahlung is investigated based on neutrino observations. The results indicate that the axion luminosity must be less than about 10 to the 53rd erg/s if: (1) axions couple very weakly (with an axion mass of less than about 0.75 x 10 to the -3rd); or (2) axions couple strongly enough to be trapped and radiated from an axion sphere with T sub a of less than about 8 MeV (with an axion mass of greater than about 2.2 eV). Axion trapping is found to occur for axion masses of greater than about 0.016 eV.

  19. Dark Axion Portal

    CERN Document Server

    Kaneta, Kunio; Yun, Seokhoon

    2016-01-01

    The dark photon and the axion (or axion-like particle) are among the popular light particles of the hidden sector. Each of them has been actively searched for through the couplings called the vector portal and the axion portal. We introduce a new portal connecting the dark photon and the axion (axion--photon--dark photon, axion--dark photon--dark photon), which emerges in the presence of the two particles. This dark axion portal is genuinely new couplings, not just from a product of the vector portal and the axion portal, because of the internal structure of these couplings. We present a simple model that realizes the dark axion portal and discuss why it warrants rich phenomenology.

  20. Dense Axion Stars

    CERN Document Server

    Braaten, Eric; Zhang, Hong

    2015-01-01

    If the dark matter consists of axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound Bose-Einstein condensates of axions. In the previously known axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure.If the axion mass energy is $mc^2= 10^{-4}$ eV, these dilute axion stars have a maximum mass of about $10^{-14} M_\\odot$. We point out that there are also dense axion stars in which gravity is balanced by the mean-field pressure of the axion condensate. We study axion stars using the leading term in a systematically improvable approximation to the effective potential of the nonrelativistic effective field theory for axions. Using the Thomas-Fermi approximation in which the kinetic pressure is neglected, we find a sequence of new branches of axion stars in which gravity is balanced by the mean-field interaction energy of the axion condensate. If $mc^2 = 10^{-4}$ eV, the first branch of these dense axion stars has mas...

  1. Dense Axion Stars

    Science.gov (United States)

    Braaten, Eric; Mohapatra, Abhishek; Zhang, Hong

    2016-09-01

    If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. The mass of these dilute axion stars cannot exceed a critical mass, which is about 10-14M⊙ if the axion mass is 10-4 eV . We study axion stars using a simple approximation to the effective potential of the nonrelativistic effective field theory for axions. We find a new branch of dense axion stars in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate. The mass on this branch ranges from about 10-20M⊙ to about M⊙ . If a dilute axion star with the critical mass accretes additional axions and collapses, it could produce a bosenova, leaving a dense axion star as the remnant.

  2. Dense Axion Stars

    Science.gov (United States)

    Mohapatra, Abhishek; Braaten, Eric; Zhang, Hong

    2016-03-01

    If the dark matter consists of axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound Bose-Einstein condensates of axions. In the previously known axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. If the axion mass energy is mc2 =10-4 eV, these dilute axion stars have a maximum mass of about 10-14M⊙ . We point out that there are also dense axion stars in which gravity is balanced by the mean-field pressure of the axion condensate. We study axion stars using the leading term in a systematically improvable approximation to the effective potential of the nonrelativistic effective field theory for axions. Using the Thomas-Fermi approximation in which the kinetic pressure is neglected, we find a sequence of new branches of axion stars in which gravity is balanced by the mean-field interaction energy of the axion condensate. If mc2 =10-4 4 eV, the first branch of these dense axion stars has mass ranging from about 10-11M⊙ toabout M⊙.

  3. The Tokyo axion helioscope

    Energy Technology Data Exchange (ETDEWEB)

    Ohta, R., E-mail: comic@icepp.s.u-tokyo.ac.jp [Department of Physics, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Akimoto, Y. [School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Inoue, Y. [International Center for Elementary Particle Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Research Center for the Early Universe (RESCEU), School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Minowa, M. [Department of Physics, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Research Center for the Early Universe (RESCEU), School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Mizumoto, T. [Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa-oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Moriyama, S. [Institute for Cosmic Ray Research, University of Tokyo, 456 Higashi-Mozumi, Kamioka-cho, Hida, Gifu 506-1205 (Japan); Namba, T. [International Center for Elementary Particle Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Takasu, Y. [Tsukuba, Ibaraki (Japan); Yamamoto, A. [High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Research Center for the Early Universe (RESCEU), School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-04-01

    The Tokyo Axion Helioscope experiment aims to detect axions which are produced in the solar core. The helioscope uses a strong magnetic field in order to convert axions into X-ray photons and has a mounting to follow the sun very accurately. The photons are detected by an X-ray detector which is made of 16 PIN-photodiodes. In addition, a gas container and a gas regulation system are adopted for recovering the coherence between axions and photons in the conversion region giving sensitivity to axions with masses up to 2 eV. In this paper, we report on the technical detail of the Tokyo Axion Helioscope.

  4. Axion beams at HERA?

    OpenAIRE

    Piotrzkowski, Krzysztof

    2007-01-01

    If the recently observed anomaly in the PVLAS experiment is due to the axion, then the powerful beams of synchrotron photons, propagating through high magnetic field of the HERA beamline, become strong axion sources. This gives a unique opportunity of detection of the axion-photon interactions by installing a small detector in the HERA tunnel, and to corroborate the axion hypothesis within a few days of running. Comment: 5 pages, 1 figure

  5. Redefining the Axion Window

    CERN Document Server

    Di Luzio, Luca; Nardi, Enrico

    2016-01-01

    A major goal of axion searches is to reach inside the parameter space region of realistic axion models. Currently, the boundaries of this region depend on somewhat arbitrary criteria, and it would be desirable to specify them in terms of precise phenomenological requirements. We consider hadronic axion models and classify the representations $R_Q$ of the new heavy quarks $Q$. By requiring that $i)$ the $Q$ are sufficiently short lived to avoid issues with long lived strongly interacting relics, $ii)$ no Landau poles are induced below the Planck scale, fifteen cases are selected, which define a phenomenologically preferred axion window bounded by a maximum (minimum) value of the axion-photon coupling about twice (four times) larger than commonly assumed. Allowing for more than one $R_Q$, larger couplings, as well as complete axion-photon decoupling, become possible.

  6. Collapse of axion stars

    Science.gov (United States)

    Eby, Joshua; Leembruggen, Madelyn; Suranyi, Peter; Wijewardhana, L. C. R.

    2016-12-01

    Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as a result, they are well described by a leading-order expansion of the axion potential. Heavier states are susceptible to gravitational collapse. Inclusion of higher-order interactions, present in the full potential, can give qualitatively different results in the analysis of collapsing heavy states, as compared to the leading-order expansion. In this work, we find that collapsing axion stars are stabilized by repulsive interactions present in the full potential, providing evidence that such objects do not form black holes. In the last moments of collapse, the binding energy of the axion star grows rapidly, and we provide evidence that a large amount of its energy is lost through rapid emission of relativistic axions.

  7. Redefining the Axion Window

    Science.gov (United States)

    Di Luzio, Luca; Mescia, Federico; Nardi, Enrico

    2017-01-01

    A major goal of axion searches is to reach inside the parameter space region of realistic axion models. Currently, the boundaries of this region depend on somewhat arbitrary criteria, and it would be desirable to specify them in terms of precise phenomenological requirements. We consider hadronic axion models and classify the representations RQ of the new heavy quarks Q . By requiring that (i) the Q 's are sufficiently short lived to avoid issues with long-lived strongly interacting relics, (ii) no Landau poles are induced below the Planck scale; 15 cases are selected which define a phenomenologically preferred axion window bounded by a maximum (minimum) value of the axion-photon coupling about 2 times (4 times) larger than is commonly assumed. Allowing for more than one RQ, larger couplings, as well as complete axion-photon decoupling, become possible.

  8. Inflationary Axion Cosmology

    Science.gov (United States)

    Wilczek, Frank; Turner, Michael S.

    1990-09-01

    If Peccei-Quinn (PQ) symmetry is broken after inflation, the initial axion angle is a random variable on cosmological scales; based on this fact, estimates of the relic-axion mass density give too large a value if the axion mass is less than about 10-6 eV. This bound can be evaded if the Universe underwent inflation after PQ symmetry breaking and if the observable Universe happens to be a region where the initial axion angle was atypically small, .1 . (ma/10-6eV)0.59. We show consideration of fluctuations induced during inflation severely constrains the latter alternative.

  9. Experimental Axion Review

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Axions are a natural consequence of the Peccei-Quinn mechanism, the most compelling solution to the strong-CP problem. Similar axion-like particles (ALPs) also appear in a number of possible extensions of the Standard Model, notably in string theories. Both axions and ALPs are very well motivated candidates for the Dark Matter, and in addition would be copiously produced at the stellar cores. Some anomalous astrophysical observations could be hinting the existence of these particles. They are object of increasing interest by experimentalists. I will briefly review the motivation to search for axions and ALPs, as well as the current status and future prospects of the experimental landscape.

  10. Inflationary axion cosmology

    Science.gov (United States)

    Turner, Michael S.; Wilczek, Frank

    1991-01-01

    If Peccei-Quinn (PQ) symmetry is broken after inflation, the initial axion angle is a random variable on cosmological scales; based on this fact, estimates of the relic-axion mass density give too large a value if the axion mass is less than about 10 to the -6th eV. This bound can be evaded if the universe underwent inflation after PQ-symmetry breaking and if the observable universe happens to be a region where the initial axion angle was atypically small. Consideration of fluctuations induced during inflation severely constrains the latter alternative is shown.

  11. Future axion searches with the International Axion Observatory (IAXO)

    DEFF Research Database (Denmark)

    Irastorza, I G; Avignone, F T; Cantatore, G

    2013-01-01

    The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensitivity to the axion-photon coupling of gaγ (≳) few × 10−12 GeV−1, i.e. 1–1.5 orders of magnitude beyond the one achieved by CAST, currently the most sensitive axion helioscope. The main elements of IAXO...

  12. Fermion dispersion in axion medium

    OpenAIRE

    Mikheev, N. V.; Narynskaya, E. N.

    2008-01-01

    The interaction of a fermion with the dense axion medium is investigated for the purpose of finding an axion medium effect on the fermion dispersion. It is shown that axion medium influence on the fermion dispersion under astrophysical conditions is negligible small if the correct Lagrangian of the axion-fermion interaction is used.

  13. (Mainly) axion dark matter

    Science.gov (United States)

    Baer, Howard

    2016-06-01

    The strong CP problem of QCD is at heart a problem of naturalness: why is the FF ˜ term highly suppressed in the QCD Lagrangian when it seems necessary to explain why there are three and not four light pions? The most elegant solution posits a spontaneously broken Peccei-Quinn (PQ) symmetry which requires the existence of the axion field a. The axion field settles to the minimum of its potential thus removing the offensive term but giving rise to the physical axion whose coherent oscillations can make up the cold dark matter. Only now are experiments such as ADMX beginning to explore QCD axion parameter space. Since a bonafide scalar particle- the Higgs boson- has been discovered, one might expect its mass to reside at the axion scale fa ˜ 1011 GeV. The Higgs mass is elegantly stabilized by supersymmetry: in this case the axion is accompanied by its axino and saxion superpartners. Requiring naturalness also in the electroweak sector implies higgsino-like WIMPs so then we expect mixed axion-WIMP dark matter. Ultimately we would expect detection of both an axion and a WIMP while signals for light higgsinos may show up at LHC and must show up at ILC.

  14. (Mainly) axion dark matter

    CERN Document Server

    Baer, Howard

    2015-01-01

    The strong CP problem of QCD is at heart a problem of naturalness: why is the F\\tilde{F} term highly suppressed in the QCD Lagrangian when it seems necessary to explain why there are three and not four light pions? The most elegant solution posits a spontaneously broken Peccei-Quinn (PQ) symmetry which requires the existence of the axion field a. The axion field settles to the minimum of its potential thus removing the offensive term but giving rise to the physical axion whose coherent oscillations can make up the cold dark matter. Only now are experiments such as ADMX beginning to explore QCD axion parameter space. Since a bonafide scalar particle-- the Higgs boson-- has been discovered, one might expect its mass to reside at the axion scale f_a~ 10^{11} GeV. The Higgs mass is elegantly stabilized by supersymmetry: in this case the axion is accompanied by its axino and saxion superpartners. Requiring naturalness also in the electroweak sector implies higgsino-like WIMPs so then we expect mixed axion-WIMP dar...

  15. Axions from wall decay

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S; Hagmann, C; Sikivie, P

    2001-01-08

    The authors discuss the decay of axion walls bounded by strings and present numerical simulations of the decay process. In these simulations, the decay happens immediately, in a time scale of order the light travel time, and the average energy of the radiated axions is {approx_equal} 7m{sub a} for v{sub a}/m{sub a} {approx_equal} 500. is found to increase approximately linearly with ln(v{sub a}/m{sub a}). Extrapolation of this behavior yields {approx_equal} 60 m{sub a} in axion models of interest.

  16. Particle physics: Axions exposed

    Science.gov (United States)

    Lombardo, Maria Paola

    2016-11-01

    Physicists are hunting for a particle called the axion that could solve two major puzzles in fundamental physics. An ambitious study calculates the expected mass of this particle, which might reshape the experimental searches. See Letter p.69

  17. Collapse of Axion Stars

    CERN Document Server

    Eby, Joshua; Suranyi, Peter; Wijewardhana, L C R

    2016-01-01

    Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as a result, they are well described by a leading-order expansion of the axion potential. Heavier states are susceptible to gravitational collapse. Inclusion of higher-order interactions, present in the full potential, can give qualitatively different results in the analysis of collapsing heavy states, as compared to the leading-order expansion. In this work, we find that collapsing axion stars are stabilized by repulsive interactions present in the full potential, providing evidence that such objects do not form black holes. These dense configurations, which are the endpoints of collapse, have extremely high binding energy, and as a result, decay through number changing $3\\,a\\rightarrow a$ interactions with an extremely short lifetime.

  18. The hunt for axions

    Energy Technology Data Exchange (ETDEWEB)

    Ringwald, Andreas

    2015-06-15

    Many theoretically well-motivated extensions of the Standard Model of particle physics predict the existence of the axion and further ultralight axion-like particles. They may constitute the mysterious dark matter in the universe and solve some puzzles in stellar and high-energy astrophysics. There are new, relatively small experiments around the globe, which started to hunt for these elusive particles and complement the accelerator based search for physics beyond the Standard Model.

  19. Hierarchical axion inflation.

    Science.gov (United States)

    Ben-Dayan, Ido; Pedro, Francisco Gil; Westphal, Alexander

    2014-12-31

    We propose a new field theory mechanism for generating an effective trans-Planckian decay constant from sub-Planckian ones. Using the minimal two axions and a hierarchy between two axion decay constants is sufficient for realizing inflation through nonperturbative effects only and with minimal tuning. The inflationary motion is kept entirely within a sub-Planckian domain. We outline possible strategies of embedding the model in a string theory setup.

  20. IAXO - The International Axion Observatory

    CERN Document Server

    Vogel, J K; Cantatore, G.; Carmona, J.M.; Caspi, S.; Cetin, S.A.; Christensen, F.E.; Dael, A.; Dafni, T.; Davenport, M.; Derbin, A.V.; Desch, K.; Diago, A.; Dudarev, A.; Eleftheriadis, C.; Fanourakis, G.; Ferrer-Ribas, E.; Galan, J.; Garcia, J.A.; Garza, J.G.; Geralis, T.; Gimeno, B.; Giomataris, I.; Gninenko, S.; Gomez, H.; Hailey, C.J.; Hiramatsu, T.; Hoffmann, D.H.H.; Iguaz, F.J.; Irastorza, I.G.; Isern, J.; Jaeckel, J.; Jakovcic, K.; Kaminski, J.; Kawasaki, M.; Krcmar, M.; Krieger, C.; Lakic, B.; Lindner, A.; Liolios, A.; Luzon, G.; Ortega, I.; Papaevangelou, T.; Pivovaroff, M.J.; Raffelt, G.; Redondo, J.; Ringwald, A.; Russenschuck, S.; Ruz, J.; Saikawa, K.; Savvidis, I.; Sekiguchi, T.; Shilon, I.; Silva, H.; ten Kate, H.H.J.; Tomas, A.; Troitsky, S.; van Bibber, K.; Vedrine, P.; Villar, J.A.; Walckiers, L.; Wester, W.; Yildiz, S.C.; Zioutas, K.

    2013-01-01

    The International Axion Observatory (IAXO) is a next generation axion helioscope aiming at a sensitivity to the axion-photon coupling of a few 10^{-12} GeV^{-1}, i.e. 1-1.5 orders of magnitude beyond sensitivities achieved by the currently most sensitive axion helioscope, the CERN Axion Solar Telescope (CAST). Crucial factors in improving the sensitivity for IAXO are the increase of the magnetic field volume together with the extensive use of x-ray focusing optics and low background detectors, innovations already successfully tested at CAST. Electron-coupled axions invoked to explain the white dwarf cooling, relic axions, and a large variety of more generic axion-like particles (ALPs) along with other novel excitations at the low-energy frontier of elementary particle physics could provide additional physics motivation for IAXO.

  1. Calculations for cosmic axion detection

    Science.gov (United States)

    Krauss, L.; Moody, J.; Wilczek, F.; Morris, D. E.

    1985-01-01

    Calculations are presented, using properly nomalized couplings and masses for Dine-Fischler-Srednicki axions, of power rates and signal temperatures for axion-photon conversion in microwave cavities. The importance of the galactic-halo axion line shape is emphasized. Spin-coupled detection as an alternative to magnetic-field-coupled detection is mentioned.

  2. Cern Axion Solar Telescope (CAST)

    CERN Multimedia

    2002-01-01

    The CERN Solar Axion Telescope, CAST, aims to shed light on a 30-year-old riddle of particle physics by detecting axions originating from the 15 million degree plasma in the Sun 's core. Axions were proposed as an extension to the Standard Model of particle physics to explain why CP violation is observed in weak but not strong interactions.

  3. Anomaly mediation deformed by axion

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Kazunori, E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8583 (Japan); Yanagida, Tsutomu T. [Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8583 (Japan)

    2013-05-13

    We show that in supersymmetric axion models the axion supermultiplet obtains a sizable F-term due to a non-supersymmetric dynamics and it generally gives the gaugino masses comparable to the anomaly mediation contribution. Thus the gaugino mass relation predicted by the anomaly mediation effect can be significantly modified in the presence of axion to solve the strong CP problem.

  4. Future axion searches with the International Axion Observatory (IAXO)

    CERN Document Server

    Irastorza, I G; Cantatore, G; Carmona, J M; Caspi, S; Cetin, S A; Christensen, F E; Dael, A; Dafni, T; Davenport, M; Derbin, A V; Desch, K; Diago, A; Döbrich, B; Dudarev, A; Eleftheriadis, C; Fanourakis, G; Ferrer-Ribas, E; Galán, J; García, J A; Garza, J.G; Geralis, T; Gimeno, B; Giomataris, I; Gninenko, S; Gómez, H; Guendelman, E; Hailey, C J; Hiramatsu, T; Hoffmann, D H H; Horns, D; Iguaz, F J; Isern, J; Jakobsen, A C; Jaeckel, J; Jakovčić, K; Kaminski, J; Kawasaki, M; Krčmar, M; Krieger, C; Lakić, B; Lindner, A; Liolios, A; Luzón, G; Ortega, I; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Redondo, J; Ringwald, A; Russenschuck, S; Ruz, J; Saikawa, K; Savvidis, I; Sekiguchi, T; Shilon, I; Sikivie, P; Silva, H; Kate, H ten; Tomas, A; Troitsky, S; Vafeiadis, T; Bibber, K van; Vedrine, P; Villar, J A; Vogel, J K; Walckiers, L; Wester, W; Yildiz, S C; Zioutas, K

    2013-01-01

    The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensitivity to the axion-photon coupling of gaγ few × 10−12 GeV−1, i.e. 1–1.5 orders of magnitude beyond the one achieved by CAST, currently the most sensitive axion helioscope. The main elements of IAXO are an increased magnetic field volume together with extensive use of x-ray focusing optics and low background detectors, innovations already successfully tested in CAST. Additional physics cases of IAXO could include the detection of electron-coupled axions invoked to explain the white dwarf cooling, relic axions, and a large variety of more generic axion-like particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics.

  5. Axion domain wall baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Daido, Ryuji; Kitajima, Naoya [Department of Physics, Tohoku University,Sendai 980-8578 (Japan); Takahashi, Fuminobu [Department of Physics, Tohoku University,Sendai 980-8578 (Japan); Kavli IPMU, TODIAS, University of Tokyo,Kashiwa 277-8583 (Japan)

    2015-07-28

    We propose a new scenario of baryogenesis, in which annihilation of axion domain walls generates a sizable baryon asymmetry. Successful baryogenesis is possible for a wide range of the axion mass and decay constant, m≃10{sup 8}–10{sup 13} GeV and f≃10{sup 13}–10{sup 16} GeV. Baryonic isocurvature perturbations are significantly suppressed in our model, in contrast to various spontaneous baryogenesis scenarios in the slow-roll regime. In particular, the axion domain wall baryogenesis is consistent with high-scale inflation which generates a large tensor-to-scalar ratio within the reach of future CMB B-mode experiments. We also discuss the gravitational waves produced by the domain wall annihilation and its implications for the future gravitational wave experiments.

  6. Dark matter in axion landscape

    Directory of Open Access Journals (Sweden)

    Ryuji Daido

    2017-02-01

    Full Text Available If there are a plethora of axions in nature, they may have a complicated potential and create an axion landscape. We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed dark matter density. In particular we focus on a case in which two (or more shift-symmetry breaking terms conspire to make the axion sufficiently light at the potential minimum. In this case the axion has a flat-bottomed potential. In contrast to the case in which a single cosine term dominates the potential, the axion abundance as well as its isocurvature perturbations are significantly suppressed. This allows an axion with a rather large mass to serve as dark matter without fine-tuning of the initial misalignment, and further makes higher-scale inflation to be consistent with the scenario.

  7. Dark matter in axion landscape

    Science.gov (United States)

    Daido, Ryuji; Kobayashi, Takeshi; Takahashi, Fuminobu

    2017-02-01

    If there are a plethora of axions in nature, they may have a complicated potential and create an axion landscape. We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed dark matter density. In particular we focus on a case in which two (or more) shift-symmetry breaking terms conspire to make the axion sufficiently light at the potential minimum. In this case the axion has a flat-bottomed potential. In contrast to the case in which a single cosine term dominates the potential, the axion abundance as well as its isocurvature perturbations are significantly suppressed. This allows an axion with a rather large mass to serve as dark matter without fine-tuning of the initial misalignment, and further makes higher-scale inflation to be consistent with the scenario.

  8. Dark Matter in Axion Landscape

    CERN Document Server

    Daido, Ryuji; Takahashi, Fuminobu

    2016-01-01

    If there are a plethora of axions in nature, they may have a complicated potential and create an axion landscape. We study a possibility that one of the axions is so light that it is cosmologically stable, explaining the observed dark matter density. In particular we focus on a case in which two (or more) shift-symmetry breaking terms conspire to make the axion sufficiently light at the potential minimum. In this case the axion has a flat-bottomed potential. In contrast to the case in which a single cosine term dominates the potential, the axion abundance as well as its isocurvature perturbations are significantly suppressed. This allows an axion with a rather large mass to serve as dark matter without fine-tuning of the initial misalignment, and further makes higher-scale inflation to be consistent with the scenario.

  9. The lifetime of axion stars

    Science.gov (United States)

    Eby, Joshua; Suranyi, Peter; Wijewardhana, L. C. R.

    2016-05-01

    We investigate the decay of condensates of scalars in a field theory defined by V (𝒜) = m2f2[1 -cos(𝒜/f)], where m and f are the mass and decay constant of the scalar field. An example of such a theory is that of the axion, in which case the condensates are called axion stars. The axion field, 𝒜, is self-adjoint. As a result, the axion number is not an absolutely conserved quantity. Therefore, axion stars are not stable and have finite lifetimes. Bound axions, localized on the volume of the star, have a coordinate uncertainty δx ˜ R ˜ 1/(maΔ), where R is the radius of the star and Δ = 1 - E0 2/ma 2. Here ma and E0 are the mass, and the ground state energy of the bound axion. Then the momentum distribution of axions has a width of δp ˜ maΔ. At strong binding, Δ = 𝒪(1), bound axions can easily transfer a sufficient amount of momentum to create and emit a free axion, leading to fast decay of the star with a transition rate Γ ˜ ma. However, when Δ ≪ 1, the momentum distribution is more restricted, and as shown in this paper, the transition rate for creating a free axion decreases as exp(-pδx) ˜exp(-Δ-1). Then sufficiently large, weakly bound axion stars, produced after the Big Bang, survive until the present time. We plot the region of their stability, limited by decay through axion loss and by gravitational instability, as a function of the mass of the axion and the mass of the star.

  10. Axion-Electromagnetic Waves

    CERN Document Server

    Visinelli, Luca

    2014-01-01

    We extend the duality symmetry between the electric and the magnetic fields to the case in which an additional axion-like term is present, and we derive the set of Maxwell's equations that preserves this symmetry. This new set of equations allows for a gauge symmetry extending the ordinary symmetry in the classical electrodynamics. We obtain explicit solutions for the new set of equations in the absence of external sources, and we discuss the implications of a new internal symmetry between the axion field and the electromagnetic gauge potential.

  11. The axion shield

    CERN Document Server

    Andrianov, A A; Mescia, F; Renau, A

    2010-01-01

    We investigate the propagation of a charged particle in a spatially constant, but time dependent, pseudoscalar background. Physically this pseudoscalar background could be provided by a relic axion density. The background leads to an explicit breaking of Lorentz invariance; as a consequence the process p-> p gamma is possible and the background acts as a shield against extremely energetic cosmic rays, an effect somewhat similar to the GZK cut-off effect. The effect is model independent and can be computed exactly. The hypothetical detection of the photons radiated via this mechanism would provide an indirect way of verifying the cosmological relevance of axions.

  12. Tunneling in axion monodromy

    Science.gov (United States)

    Brown, Jon; Cottrell, William; Shiu, Gary; Soler, Pablo

    2016-10-01

    The Coleman formula for vacuum decay and bubble nucleation has been used to estimate the tunneling rate in models of axion monodromy in recent literature. However, several of Coleman's original assumptions do not hold for such models. Here we derive a new estimate with this in mind using a similar Euclidean procedure. We find that there are significant regions of parameter space for which the tunneling rate in axion monodromy is not well approximated by the Coleman formula. However, there is also a regime relevant to large field inflation in which both estimates parametrically agree. We also briefly comment on the applications of our results to the relaxion scenario.

  13. Tunneling in Axion Monodromy

    CERN Document Server

    Brown, Jon; Shiu, Gary; Soler, Pablo

    2016-01-01

    The Coleman formula for vacuum decay and bubble nucleation has been used to estimate the tunneling rate in models of axion monodromy in recent literature. However, several of Coleman's original assumptions do not hold for such models. Here we derive a new estimate with this in mind using a similar Euclidean procedure. We find that there are significant regions of parameter space for which the tunneling rate in axion monodromy is not well approximated by the Coleman formula. However, there is also a regime relevant to large field inflation in which both estimates parametrically agree. We also briefly comment on the applications of our results to the relaxion scenario.

  14. The Lifetime of Axion Stars

    CERN Document Server

    Eby, Joshua; Wijewardhana, L C R

    2015-01-01

    We investigate the decay of condensates of scalars in a field theory defined by $V({\\cal A})=m^2 f^2 [1-\\cos({\\cal A}/f)]$, where $m$ and $f$ are the mass and decay constant of the scalar field. An example of such a theory is that of the axion, in which case the condensates are called axion stars. The axion field, $\\cal A$, is self adjoint. As a result the axion number is not an absolutely conserved quantity. Therefore, axion stars are not stable and have finite lifetimes. Bound axions, localized on the volume of the star, have a coordinate uncertainty $\\Delta x \\sim R \\sim 1/(m_a \\Delta)$, where $R$ is the radius of the star and $\\Delta = \\sqrt{1-E_0^2/m_a^2}$. Here $m_a$ and $E_0$ are the mass and the ground state energy of the bound axion. Then the momentum distribution of axions has a width of $\\Delta p \\sim m_a\\Delta$. At strong binding, $\\Delta={\\cal O}(1)$, bound axions can easily transfer a sufficient amount of momentum to create and emit a free axion, leading to fast decay of the star with a transiti...

  15. Constraints on small-field axion inflation

    OpenAIRE

    Kobayashi, Tatsuo; Oikawa, Akane; Omoto, Naoya; Otsuka, Hajime; Saga, Ikumi

    2016-01-01

    We study general class of small-field axion inflations which are the mixture of polynomial and sinusoidal functions suggested by the natural and axion monodromy inflations. The axion decay constants leading to the successful axion inflations are severely constrained in order not to spoil the Big-Bang nucleosynthesis and overproduce the isocurvature perturbation originating from the QCD axion. We in turn find that the cosmologically favorable axion decay constants are typically of order the gr...

  16. RELAY RACE

    CERN Multimedia

    Staff Association

    2013-01-01

    Well done to all runners, the fans and the organizers of this great race which took place on Thursday 23rd May! You were many to participate in the run or by supporting your colleagues. The Staff Association contributed with its team of runners and also with its information stall where you could meet with your delegates.  

  17. Axion inflation with cross-correlated axion isocurvature perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Kadota, Kenji [Center for Theoretical Physics of the Universe, Institute for Basic Science,Daejeon 305-811 (Korea, Republic of); Kobayashi, Tatsuo [Department of Physics, Hokkaido University,Sapporo 060-0810 (Japan); Otsuka, Hajime [Department of Physics, Waseda University,Tokyo 169-8555 (Japan)

    2016-01-25

    We study the inflation scenarios, in the framework of superstring theory, where the inflaton is an axion producing the adiabatic curvature perturbations while there exists another light axion producing the isocurvature perturbations. We discuss how the non-trivial couplings among string axions can generically arise, and calculate the consequent cross-correlations between the adiabatic and isocurvature modes through concrete examples. Based on the Planck analysis on the generally correlated isocurvature perturbations, we show that there is a preference for the existence of the correlated isocurvature modes for the axion monodromy inflation while the natural inflation disfavors such isocurvature modes.

  18. Axion inflation with cross-correlated axion isocurvature perturbations

    CERN Document Server

    Kadota, Kenji; Otsuka, Hajime

    2015-01-01

    We study the inflation scenarios, in the framework of superstring theory, where the inflaton is an axion producing the adiabatic curvature perturbations while there exists another light axion producing the isocurvature perturbations. We discuss how the non-trivial couplings among string axions can generically arise, and calculate the consequent cross-correlations between the adiabatic and isocurvature modes through concrete examples. Based on the Planck analysis on the generally correlated isocurvature perturbations, we show that there is a preference for the existence of the correlated isocurvature modes for the axion monodromy inflation while the natural inflation disfavors such isocurvature modes.

  19. Structure of axionic domain walls

    Science.gov (United States)

    Huang, M. C.; Sikivie, P.

    1985-09-01

    The structure of axionic domain walls is investigated using the low-energy effective theory of axions and pions. We derive the spatial dependence of the phases of the Peccei-Quinn scalar field and the QCD quark-antiquark condensates inside an axionic domain wall. Thence an accurate estimate of the wall surface energy density is obtained. The equations of motion for axions, photons, leptons, and baryons in the neighborhood of axionic domain walls are written down and estimates are given for the wall reflection and transmission coefficients of these particles. Finally, we discuss the energy dissipation by axionic domain walls oscillating in the early universe due to the reflection of particles in the primordial soup.

  20. Structure of axionic domain walls

    Energy Technology Data Exchange (ETDEWEB)

    Huang, M.C.; Sikivie, P.

    1985-09-15

    The structure of axionic domain walls is investigated using the low-energy effective theory of axions and pions. We derive the spatial dependence of the phases of the Peccei-Quinn scalar field and the QCD quark-antiquark condensates inside an axionic domain wall. Thence an accurate estimate of the wall surface energy density is obtained. The equations of motion for axions, photons, leptons, and baryons in the neighborhood of axionic domain walls are written down and estimates are given for the wall reflection and transmission coefficients of these particles. Finally, we discuss the energy dissipation by axionic domain walls oscillating in the early universe due to the reflection of particles in the primordial soup.

  1. Axions in astrophysics and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Sikivie, P.

    1984-07-01

    Axion models often have a spontaneously broken exact discrete symmetry. In that case, they have discretely degenerate vacua and hence domain walls. The properties of the domain walls, the cosmological catastrophe they produce and the ways in which this catastrophe may be avoided are explained. Cosmology and astrophysics provide arguments that imply the axion decay constant should lie in the range 10/sup 8/ GeV less than or equal to f/sub a/ less than or equal to 10/sup 12/ GeV. Reasons are given why axions are an excellent candidate to constitute the dark matter of galactic halos. Using the coupling of the axions to the electromagnetic field, detectors are described to look for axions floating about in the halo of our galaxy and for axions emitted by the sun. (LEW)

  2. Axions and SN1987A

    Science.gov (United States)

    Burrows, Adam; Turner, Michael S.; Brinkmann, R. P.

    1988-01-01

    The effect of free-streaming axion emission on numerical models for the cooling of the newly born neutron star associated with SN1987A is considered. It is found that for an axion mass of greater than approximately 10 to the -3 eV, axion emission shortens the duration of the expected neutrino burst so significantly that it would be inconsistent with the neutrino observations made by the Kamiokande II and Irvine-Michigan-Brookhaven detectors. However, the possibility has not been investigated that axion trapping (which should occur for masses greater than or equal to 0.02 eV) sufficiently reduces axion emission so that axion masses greater than approximately 2 eV would be consistent with the neutrino observations.

  3. Axions in String Theory

    Energy Technology Data Exchange (ETDEWEB)

    Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC; Witten, Edward; /Princeton, Inst. Advanced Study

    2006-06-09

    In the context of string theory, axions appear to provide the most plausible solution of the strong CP problem. However, as has been known for a long time, in many string-based models, the axion coupling parameter Fa is several orders of magnitude higher than the standard cosmological bounds. We re-examine this problem in a variety of models, showing that Fa is close to the GUT scale or above in many models that have GUT-like phenomenology, as well as some that do not. On the other hand, in some models with Standard Model gauge fields supported on vanishing cycles, it is possible for Fa to be well below the GUT scale.

  4. The QCD axion from aligned axions and diphoton excess

    Directory of Open Access Journals (Sweden)

    Tetsutaro Higaki

    2016-04-01

    Full Text Available We argue that the QCD axion can arise from many aligned axions with decay constants much smaller than the conventional axion window. If the typical decay constant is of O(100 GeV to 1 TeV, one or more of the axions or saxions may account for the recently found diphoton excess at ∼750 GeV. Our scenario predicts many axions and saxions coupled to gluons with decay constants of order the weak scale, and therefore many collider signatures by heavy axions and saxions will show up at different energy scales. In particular, if the inferred broad decay width is due to multiple axions or saxions, a non-trivial peak structure may become evident when more data is collected. We also discuss cosmological implications of the aligned QCD axion scenario. In the Appendix we give a possible UV completion and argue that the high quality of the Peccei–Quinn symmetry is naturally explained in our scenario.

  5. Relay race

    CERN Multimedia

    Staff Association

    2011-01-01

    The CERN relay race will take place around the Meyrin site on Thursday 19th May starting at 12·15. If possible, please avoid driving on the site during this 20-minute period. If you do meet runners while driving your car, please STOP until they have all passed. Thank you for your cooperation. Details on the course, and how to register your team for the relay race, can be found at: https://espace.cern.ch/Running-Club/CERN-Relay Some advice for all runners from the medical service can also be found here: https://espace.cern.ch/Running-Club/CERN-Relay/RelayPagePictures/MedicalServiceAnnoncement.pdf

  6. Relay race

    CERN Multimedia

    Staff Association

    2011-01-01

    The CERN relay race will take place around the Meyrin site on Thursday 19th May starting at 12:15. If possible, please avoid driving on the site during this 20-minute period. If you do meet runners while driving your car, please STOP until they have all passed. Thank you for your cooperation. Details on the course, and how to register your team for the relay race, can be found at: https://espace.cern.ch/Running-Club/CERN-Relay Some advice for all runners from the medical service can also be found here: https://espace.cern.ch/Running-Club/CERN-Relay/RelayPagePictures/MedicalServiceAnnoncement.pdf

  7. Level Crossing between QCD Axion and Axion-Like Particle

    CERN Document Server

    Daido, Ryuji; Takahashi, Fuminobu

    2015-01-01

    We study a level crossing between the QCD axion and an axion-like particle, focusing on the recently found phenomenon, the axion roulette, where the axion-like particle runs along the potential, passing through many crests and troughs, until it gets trapped in one of the potential minima. We perform detailed numerical calculations to determine the parameter space where the axion roulette takes place, and as a result domain walls are likely formed. The domain wall network without cosmic strings is practically stable, and it is nothing but a cosmological disaster. In a certain case, one can make domain walls unstable and decay quickly by introducing an energy bias without spoiling the Peccei-Quinn solution to the strong CP problem.

  8. Axion experiment makes its debut

    CERN Multimedia

    Dumé, Belle

    2004-01-01

    An experiment built from components recycled from other experiments has put new limits on the properties of particles that might be the "dark matter" that makes up about 25% of the universe. The CERN Axion Solar telescope (CAST) was built to search for exotic particles called axions that might be produced inside the sun (1 page)

  9. Constraints on small-field axion inflation

    CERN Document Server

    Kobayashi, Tatsuo; Omoto, Naoya; Otsuka, Hajime; Saga, Ikumi

    2016-01-01

    We study general class of small-field axion inflations which are the mixture of polynomial and sinusoidal functions suggested by the natural and axion monodromy inflations. The axion decay constants leading to the successful axion inflations are severely constrained in order not to spoil the Big-Bang nucleosynthesis and overproduce the isocurvature perturbation originating from the QCD axion. We in turn find that the cosmologically favorable axion decay constants are typically of order the grand unification scale or the string scale which is consistent with the prediction of closed string axions.

  10. Axion dark matter detection using atomic transitions.

    Science.gov (United States)

    Sikivie, P

    2014-11-14

    Dark matter axions may cause transitions between atomic states that differ in energy by an amount equal to the axion mass. Such energy differences are conveniently tuned using the Zeeman effect. It is proposed to search for dark matter axions by cooling a kilogram-sized sample to millikelvin temperatures and count axion induced transitions using laser techniques. This appears to be an appropriate approach to axion dark matter detection in the 10^{-4}  eV mass range.

  11. Axion Dark Matter Detection using Atomic Transitions

    CERN Document Server

    Sikivie, P

    2014-01-01

    Dark matter axions may cause transitions between atomic states that differ in energy by an amount equal to the axion mass. Such energy differences are conveniently tuned using the Zeeman effect. It is proposed to search for dark matter axions by cooling a kilogram-sized sample to milliKelvin temperatures and count axion induced transitions using laser techniques. This appears an appropriate approach to axion dark matter detection in the $10^{-4}$ eV mass range.

  12. Magnetogenesis from axion inflation

    Science.gov (United States)

    Adshead, Peter; Giblin, John T., Jr.; Scully, Timothy R.; Sfakianakis, Evangelos I.

    2016-10-01

    In this work we compute the production of magnetic fields in models of axion inflation coupled to the hypercharge sector of the Standard Model through a Chern-Simons interaction term. We make the simplest choice of a quadratic inflationary potential and use lattice simulations to calculate the magnetic field strength, helicity and correlation length at the end of inflation. For small values of the axion-gauge field coupling strength the results agree with no-backreaction calculations and estimates found in the literature. For larger couplings the helicity of the magnetic field differs from the no-backreaction estimate and depends strongly on the comoving wavenumber. We estimate the post-inflationary evolution of the magnetic field based on known results for the evolution of helical and non-helical magnetic fields. The magnetic fields produced by axion inflation with large couplings to U(1)Y can reach Beff gtrsim 10-16 G, exhibiting a field strength Bphys ≈ 10-13 G and a correlation length λphys ≈10 pc. This result is insensitive to the exact value of the coupling, as long as the coupling is large enough to allow for instantaneous preheating. Depending on the assumptions for the physical processes that determine blazar properties, these fields can be found consistent with blazar observations based on the value of Beff. Finally, the intensity of the magnetic field for large coupling can be enough to satisfy the requirements for a recently proposed baryogenesis mechanism, which utilizes the chiral anomaly of the Standard Model.

  13. Axions and White Dwarfs

    CERN Document Server

    Isern, J; Garcia-Berro, E; Salaris, M; Torres, S

    2010-01-01

    White dwarfs are almost completely degenerate objects that cannot obtain energy from the thermonuclear sources and their evolution is just a gravothermal process of cooling. The simplicity of these objects, the fact that the physical inputs necessary to understand them are well identified, although not always well understood, and the impressive observational background about white dwarfs make them the most well studied Galactic population. These characteristics allow to use them as laboratories to test new ideas of physics. In this contribution we discuss the robustness of the method and its application to the axion case.

  14. Planckian Axions in String Theory

    OpenAIRE

    Bachlechner, Thomas; Long, Cody; McAllister, Liam

    2014-01-01

    We argue that super-Planckian diameters of axion fundamental domains can naturally arise in Calabi-Yau compactifications of string theory. In a theory with $N$ axions $\\theta^i$, the fundamental domain is a polytope defined by the periodicities of the axions, via constraints of the form $-\\piN$ constraints, while for $P=N$ the diameter is further enhanced by eigenvector delocalization to $N^{3/2}f_N$. We directly verify our results in explicit Calabi-Yau compactifications of type IIB string t...

  15. Semiclassical gravity and invisible axions

    CERN Document Server

    Holman, R; Rey, S J; Rey, Soo-Jong

    1993-01-01

    We show that charged Eguchi-Hanson instantons provide a concrete and calculable new source of intrinsic Peccei-Quinn symmetry breaking by quantum gravity. The size of this breaking is shown to depend sensitively on the short distance details of a given theory, but is generically suppressed by fermion zero modes. Demanding that these gravitational effects not affet the axion solution to the strong CP problem, we find that at least two sets of quarks with differing Peccei-Quinn charges are required. In addition, these effects obviate the cosmological axion domain wall problem but leave unchanged problems associated with coherent axion oscillations.

  16. Laser-induced axion photoproduction

    Science.gov (United States)

    Brodsky, S. J.; Mottola, E.; Muzinich, I. J.; Soldate, M.

    1986-01-01

    Axion photoproduction is suggested as a systematic technique for investigating the coupling of new elementary pseudoscalar or scalar particles in the megaelectronvolt mass range to leptons, photons, and hadronic matter. The experiments involve a configuration where a low-energy photon collides with a relativistic electron beam. Threshold production energies of 300 GeV can be accomplished with an optical laser, and those of 14.5-50 GeV can be achieved with wigglers directed onto an electron beam. With this scheme, at least 10 to the -7th of the electrons can be converted to axions, providing a 1-100 thousand/s relativistic beam of axions.

  17. Eclipses could clarify axion mystery

    CERN Multimedia

    2007-01-01

    "Physicists in Europe have proposed an outlandish experiment that could determine once and for all whether ultralight particles called axions - one of the leading candidates for dark matter - exist." (1/2 page)

  18. Axion cosmology in the laboratory

    CERN Document Server

    Beck, Christian

    2010-01-01

    What do advanced Josephson junction technologies, SQUIDs, coupled Josephson qubits and related superconducting devices used in nanotechnology have in common with the problem of dark matter in the early universe? A lot more than might seem obvious at first sight, as will be shown in this letter. One of the major candidates for dark matter in the universe is the axion. The equation of motion of the axion misalignment angle and that of the phase difference in a Josephson junction are identical if the symbols in the mathematical equations are properly re-interpreted. This allows for analogue simulation of early-universe physics using superconducting electronic devices such as SQUIDs and Josephson junctions. It also allows for new experimental setups that test axionic interaction strengths in a Josephson junction environment, similar in nature to recent experiments that test for quantum entanglement of two coupled Josephson qubits. The parameter values relevant for early-universe axion cosmology are accessible wit...

  19. Axion Isocurvature and Magnetic Monopoles.

    Science.gov (United States)

    Nomura, Yasunori; Rajendran, Surjeet; Sanches, Fabio

    2016-04-08

    We propose a simple mechanism to suppress axion isocurvature fluctuations using hidden sector magnetic monopoles. This allows for the Peccei-Quinn scale to be of the order of the unification scale consistently with high scale inflation.

  20. Two applications of axion electrodynamics

    Science.gov (United States)

    Wilczek, Frank

    1987-01-01

    The equations of axion electrodynamics are studied. Variations in the axion field can give rise to peculiar distributions of charge and current. These effects provide a simple understanding of the fractional electric charge on dyons and of some recently discovered oddities in the electrodynamics of antiphase boundaries in PbTe. Some speculations regarding the possible occurrence of related phenomena in other solids are presented.

  1. The Amazing Mathematical Race

    Science.gov (United States)

    Noblitt, Bethany A.; Buckley, Brooke E.

    2011-01-01

    Teams, pit stops, clues, time limits, fast forwards, challenges, and prizes are all components of the CBS hit show "The Amazing Race." They were also elements of the Amazing Mathematical Race sponsored by the Math and Stats Club at Northern Kentucky University in April 2009. Held in recognition of Math Awareness Month, which is advocated…

  2. The Next Generation of Axion Helioscopes: The International Axion Observatory (IAXO)

    DEFF Research Database (Denmark)

    Vogel, J.K.; Armengaud, E.; Avignone, F.T.;

    2015-01-01

    The International Axion Observatory (IAXO) is a proposed 4th-generation axion helioscope with the primary physics research goal to search for solar axions via their Primakoff conversion into photons of 1 – 10 keV energies in a strong magnetic field. IAXO will achieve a sensitivity to the axion...

  3. Portal Connecting Dark Photons and Axions

    Science.gov (United States)

    Kaneta, Kunio; Lee, Hye-Sung; Yun, Seokhoon

    2017-03-01

    The dark photon and the axion (or axionlike particle) are popular light particles of the hidden sector. Each of them has been actively searched for through the couplings called the vector portal and the axion portal. We introduce a new portal connecting the dark photon and the axion (axion-photon-dark photon, axion-dark photon-dark photon), which emerges in the presence of the two particles. This dark axion portal is genuinely new couplings, not just from a product of the vector portal and the axion portal, because of the internal structure of these couplings. We present a simple model that realizes the dark axion portal and discuss why it warrants a rich phenomenology.

  4. Aligned natural inflation: Monodromies of two axions

    Directory of Open Access Journals (Sweden)

    Rolf Kappl

    2014-10-01

    Full Text Available Natural (axionic inflation [1] can accommodate sizeable primordial tensor modes but suffers from the necessity of trans-Planckian variations of the inflaton field. This problem can be solved via the mechanism of aligned axions [2], where the aligned axion spirals down in the potential of other axions. We elaborate on the mechanism in view of the recently reported observations of the BICEP2 collaboration [3].

  5. Aligned natural inflation: Monodromies of two axions

    Energy Technology Data Exchange (ETDEWEB)

    Kappl, Rolf, E-mail: kappl@th.physik.uni-bonn.de; Krippendorf, Sven, E-mail: krippendorf@th.physik.uni-bonn.de; Nilles, Hans Peter, E-mail: nilles@th.physik.uni-bonn.de

    2014-10-07

    Natural (axionic) inflation [1] can accommodate sizeable primordial tensor modes but suffers from the necessity of trans-Planckian variations of the inflaton field. This problem can be solved via the mechanism of aligned axions [2], where the aligned axion spirals down in the potential of other axions. We elaborate on the mechanism in view of the recently reported observations of the BICEP2 collaboration [3].

  6. New confining force solution of QCD axion domain wall problem

    OpenAIRE

    Barr, S. M.; Kim, Jihn E.

    2014-01-01

    The serious cosmological problems created by the axion-string/axion-domain-wall system in standard axion models are alleviated by positing the existence of a new confining force. The instantons of this force can generate an axion potential that erases the axion strings long before QCD effects become important, thus preventing QCD-generated axion walls from ever appearing. Axion walls generated by the new confining force would decay so early as not to contribute significantly to the energy in ...

  7. Active galaxies can make axionic dark energy

    Science.gov (United States)

    Dimopoulos, Konstantinos; Cormack, Sam

    2016-12-01

    AGN jets carry helical magnetic fields, which can affect dark matter if the latter is axionic. This preliminary study shows that, in the presence of strong helical magnetic fields, the nature of the axionic condensate may change and become dark energy. Such dark energy may affect galaxy formation and galactic dynamics, so this possibility should not be ignored when considering axionic dark matter.

  8. Experimental Searches for the Axion and Axion-like Particles

    CERN Document Server

    Graham, Peter W; Lamoreaux, Steven K; Lindner, Axel; van Bibber, Karl A

    2016-01-01

    Four decades after its prediction, the axion remains the most compelling solution to the Strong-CP problem and a well-motivated dark matter candidate, inspiring a host of elegant and ultrasensitive experiments based on axion-photon mixing. This report reviews the experimental situation on several fronts. The microwave cavity experiment is making excellent progress in the search for dark matter axions in the microelectronvolt range and may be plausibly extended up to 100 mu eV. Within the past several years however, it has been realized that axions are pervasive throughout string theories, but with masses that fall naturally in the nanoelectronvolt range, for which a NMR-based search is under development. Searches for axions emitted from the Sun's burning core, and purely laboratory experiments based on photon regeneration have both made great strides in recent years, with ambitious projects proposed for the coming decade. Each of these campaigns has pushed the state of the art in technology, enabling large ga...

  9. Planckian Axions in String Theory

    CERN Document Server

    Bachlechner, Thomas C; McAllister, Liam

    2014-01-01

    We argue that super-Planckian diameters of axion fundamental domains can naturally arise in Calabi-Yau compactifications of string theory. In a theory with $N$ axions $\\theta^i$, the fundamental domain is a polytope defined by the periodicities of the axions, via constraints of the form $-\\pi\\sqrt{N}$. This result is robust in the presence of $P>N$ constraints, while for $P=N$ the diameter is further enhanced by eigenvector delocalization to $N^{3/2}f_N$. We directly verify our results in explicit Calabi-Yau compactifications of type IIB string theory. In the classic example with $h^{1,1}=51$ where parametrically controlled moduli stabilization was demonstrated by Denef et al. in [1], the largest metric eigenvalue obeys $f_N \\approx 0.013 M_{pl}$. The random matrix analysis then predicts, and we exhibit, axion diameters $>M_{pl}$ for the precise vacuum parameters found in [1]. Our results provide a framework for achieving large-field axion inflation in well-understood flux vacua.

  10. Planckian axions in string theory

    Science.gov (United States)

    Bachlechner, Thomas C.; Long, Cody; McAllister, Liam

    2015-12-01

    We argue that super-Planckian diameters of axion fundamental domains can arise in Calabi-Yau compactifications of string theory. In a theory with N axions θ i , the fundamental domain is a polytope defined by the periodicities of the axions, via constraints of the form - π √{N} . This result is robust in the presence of P > N constraints, while for P = N the diameter is further enhanced by eigenvector delocalization to N 3/2 f N . We directly verify our results in explicit Calabi-Yau compactifications of type IIB string theory. In the classic example with h 1,1 = 51 where parametrically controlled moduli stabilization was demonstrated by Denef et al. in [1], the largest metric eigenvalue obeys f N ≈ 0.013 M pl. The random matrix analysis then predicts, and we exhibit, axion diameters ≈ M pl for the precise vacuum parameters found in [1]. Our results provide a framework for pursuing large-field axion inflation in well-understood flux vacua.

  11. Axion landscape and natural inflation

    Directory of Open Access Journals (Sweden)

    Tetsutaro Higaki

    2015-05-01

    Full Text Available Multiple axions form a landscape in the presence of various shift symmetry breaking terms. Eternal inflation populates the axion landscape, continuously creating new universes by bubble nucleation. Slow-roll inflation takes place after the tunneling event, if a very flat direction with a super-Planckian decay constant arises due to the alignment mechanism. We study the vacuum structure as well as possible inflationary dynamics in the axion landscape scenario, and find that the inflaton dynamics is given by either natural or multi-natural inflation. In the limit of large decay constant, it is approximated by the quadratic chaotic inflation, which however is disfavored if there is a pressure toward shorter duration of inflation. Therefore, if the spectral index and the tensor-to-scalar ratio turn out to be different from the quadratic chaotic inflation, there might be observable traces of the bubble nucleation. Also, the existence of small modulations to the inflaton potential is a common feature in the axion landscape, which generates a sizable and almost constant running of the scalar spectral index over CMB scales. Non-Gaussianity of equilateral type can also be generated if some of the axions are coupled to massless gauge fields.

  12. Axion landscape and natural inflation

    Energy Technology Data Exchange (ETDEWEB)

    Higaki, Tetsutaro, E-mail: thigaki@post.kek.jp [Theory Center, KEK, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Takahashi, Fuminobu, E-mail: fumi@tuhep.phys.tohoku.ac.jp [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, University of Tokyo, Kashiwa 277-8583 (Japan)

    2015-05-11

    Multiple axions form a landscape in the presence of various shift symmetry breaking terms. Eternal inflation populates the axion landscape, continuously creating new universes by bubble nucleation. Slow-roll inflation takes place after the tunneling event, if a very flat direction with a super-Planckian decay constant arises due to the alignment mechanism. We study the vacuum structure as well as possible inflationary dynamics in the axion landscape scenario, and find that the inflaton dynamics is given by either natural or multi-natural inflation. In the limit of large decay constant, it is approximated by the quadratic chaotic inflation, which however is disfavored if there is a pressure toward shorter duration of inflation. Therefore, if the spectral index and the tensor-to-scalar ratio turn out to be different from the quadratic chaotic inflation, there might be observable traces of the bubble nucleation. Also, the existence of small modulations to the inflaton potential is a common feature in the axion landscape, which generates a sizable and almost constant running of the scalar spectral index over CMB scales. Non-Gaussianity of equilateral type can also be generated if some of the axions are coupled to massless gauge fields.

  13. The Axion Mass in Modular Invariant Supergravity

    CERN Document Server

    Butter, D; Butter, Daniel; Gaillard, Mary K.

    2005-01-01

    When supersymmetry is broken by condensates with a single condensing gauge group, there is a nonanomalous R-symmetry that prevents the universal axion from acquiring a mass. It has been argued that, in the context of supergravity, higher dimension operators will break this symmetry and may generate an axion mass too large to allow the identification of the universal axion with the QCD axion. We show that such contributions to the axion mass are highly suppressed in a class of models where the effective Lagrangian for gaugino and matter condensation respects modular invariance (T-duality).

  14. The photo-philic QCD axion

    CERN Document Server

    Farina, Marco; Rompineve, Fabrizio; Tesi, Andrea

    2016-01-01

    We propose a framework in which the QCD axion has an exponentially large coupling to photons, relying on the "clockwork" mechanism. We discuss the impact of present and future axion experiments on the parameter space of the model. In addition to the axion, the model predicts a large number of pseudo-scalars which can be light and observable at the LHC. In the most favorable scenario, axion Dark Matter will give a signal in multiple axion detection experiments and the pseudo-scalars will be discovered at the LHC, allowing to determine most of the parameters of the model.

  15. Improved estimation of radiated axions from cosmological axionic strings

    CERN Document Server

    Hiramatsu, Takashi; Sekiguchi, Toyokazu; Yamaguchi, Masahide; Yokoyama, Jun'ichi

    2010-01-01

    Cosmological evolution of axionic string network is analyzed in terms of field-theoretic simulations in a box of 512^3 grids, which are the largest ever, using a new and more efficient identification scheme of global strings. The scaling parameter is found to be \\xi=0.87 +- 0.14 in agreement with previous results. The energy spectrum is calculated precisely using a pseudo power spectrum estimator which significantly reduces the error in the mean reciprocal comoving momentum. The resultant constraint on the axion decay constant leads to f_a <= 3*10^11 GeV. We also discuss implications for the early Universe.

  16. Inflationary dilaton-axion magnetogenesis

    CERN Document Server

    Cheng, Shu-Lin; Ng, Kin-Wang

    2014-01-01

    We discuss the generation of primordial magnetic fields during inflation in the dilaton-axion electromagnetism, in which the dilaton and axion dynamics are introduced in terms of two time dependent functions of the cosmic scale factor, $I(a) F^2/4$ and $J(a) F\\tilde{F}/4$, respectively, where $F$ is the electromagnetic field strength and $\\tilde{F}$ is its dual. We study the form of $J(a)$ that can generate a large seed magnetic field in the weak coupling regime, $I(a)<1$. Although the $J(a)$ function is model dependent, the axion-photon coupling indeed opens up a new window for a successful inflationary magnetogenesis.

  17. Axion dark matter: strings and their cores

    Energy Technology Data Exchange (ETDEWEB)

    Fleury, Leesa [McGill University, Department of Physics,3600 rue University, Montréal QC H3A 2T8 (Canada); Moore, Guy D. [Institut für Kernphysik, Technische Universität Darmstadt,Schlossgartenstraße 2, D-64289 Darmstadt (Germany)

    2016-01-04

    Axions constitute a well-motivated dark matter candidate, and if PQ symmetry breaking occurred after inflation, it should be possible to make a clean prediction for the relation between the axion mass and the axion dark matter density. We show that axion (or other global) string networks in 3D have a network density that depends logarithmically on the string separation-to-core ratio. This logarithm would be about 10 times larger in axion cosmology than what we can achieve in numerical simulations. We simulate axion production in the early Universe, finding that, for the separation-to-core ratios we can achieve, the changing density of the network has little impact on the axion production efficiency.

  18. Axion hot dark matter bounds

    CERN Document Server

    Raffelt, G; Mirizzi, A; Wong, Y Y Y

    2008-01-01

    We derive cosmological limits on two-component hot dark matter consisting of neutrinos and axions. We restrict the large-scale structure data to the safely linear regime, excluding the Lyman-alpha forest. We derive Bayesian credible regions in the two-parameter space consisting of m_a and sum(m_nu). Marginalizing over sum(m_nu) provides m_a<1.02 eV (95% CL). In the absence of axions the same data and methods give sum(m_nu)< 0.63 eV (95% CL).

  19. Relay race

    CERN Multimedia

    Staff Association

    2012-01-01

    The CERN Relay Race will take place around the Meyrin site on Thursday 24th May at 12:00. This annual event is for teams of six runners covering distances of 1000 m, 800 m, 800 m, 500 m, 500 m and 300 m respectively. Teams may be entered in the Seniors, Veterans, Ladies, Mixed or Open categories. There will also this year be a Nordic Walking event, as part of the Medical Service’s initiative “Move more, eat better!” The registration fee is 10 CHF per runner, and each runner will receive a souvenir prize. There will be a programme of entertainment from 12:00 on the arrival area (the lawn in front of Restaurant 1): 12:00 - 12:45  Music from the Old Bottom Street band 12:15 Start of the race 12:45 - 13h Demonstrations by the Fitness club and Dancing club 13:00 Results and prize giving (including a raffle to win an iPad2 3G offered by the Micro club) 13:20 à 14:00 Music from “What’s next” And many information st...

  20. Axion Cooling of Neutron Stars

    CERN Document Server

    Sedrakian, Armen

    2015-01-01

    Cooling simulations of neutron stars and their comparison with the data from thermally emitting X-ray sources puts constraints on the properties of axions, and by extension of any light pseudo-scalar dark matter particles, whose existence has been postulated to solve the strong-CP problem of QCD. We incorporate the axion emission by pair-breaking and formation processes by $S$- and $P$-wave nucleonic condensates in a benchmark code for cooling simulations as well as provide fit formulae for the rates of these processes. Axion cooling of neutron stars has been simulated for 24 models covering the mass range 1 to 1.8 solar masses, featuring non-accreted iron and accreted light element envelopes, and a range of nucleon-axion coupling. The models are based on an equation state predicting conservative physics of superdense nuclear matter that does not allow for onset of fast cooling processes induced by phase transitions to non-nucleonic forms of matter or high proton concentration. The cooling tracks in the tempe...

  1. Axion cooling of white dwarfs

    CERN Document Server

    Isern, J; Garcia--Berro, E; Salaris, M; Torres, S

    2013-01-01

    The evolution of white dwarfs is a simple gravothermal process. This process can be tested in two ways, through the luminosity function of these stars and through the secular variation of the period of pulsation of those stars that are variable. Here we show how the mass of the axion can be constrained using the white dwarf luminosity function.

  2. Ultrasensitive searches for the axion

    CERN Multimedia

    Van Bibber, Karl

    2006-01-01

    "The axion is a hypothetical particle with a mass possibly a trillion times lighter than an electron and exceedingly small couplings to ordinary matter. Yet experiments may soon detect its presence, either as dark matter or as a component of solar flux." (6 pages)

  3. Magnetic Scope Angles for Axions

    CERN Multimedia

    Seife, Charles

    2005-01-01

    After 2 years of staring at the sun, an unconventional "telescope" made from a leftover magnet has returned its first results. Although it hasn't yet found the quarry it was designed to spot - a particle that might or might not exist physicists say the CERN Axion Solar Telescope (CAST) is beginning to glimpse uncharted territory

  4. Axion emission from neutron stars

    Science.gov (United States)

    Iwamoto, N.

    1984-01-01

    It is shown that axion emission from neutron stars is the dominant energy-loss mechanism for a range of values of the Peccei-Quinn symmetry-breaking scale (F) not excluded by previous constraints. This gives the possibility of obtaining a better bound on F from measurements of surface temperature of neutron stars.

  5. Axion as a cold dark matter candidate: Analysis to third order perturbation for classical axion

    CERN Document Server

    Noh, Hyerim; Park, Chan-Gyung

    2015-01-01

    We investigate aspects of axion as a coherently oscillating massive classical scalar field by analyzing third order perturbations in Einstein's gravity in the axion-comoving gauge. The axion fluid has its characteristic pressure term leading to an axion Jeans scale which is cosmologically negligible for a canonical axion mass. Our classically derived axion pressure term in Einstein's gravity is identical to the one derived in the non-relativistic quantum mechanical context in the literature. We show that except for the axion pressure term, the axion fluid equations are exactly the same as the general relativistic continuity and Euler equations of a zero-pressure fluid up to third order perturbation. The general relativistic density and velocity perturbations of the CDM in the CDM-comoving gauge are exactly the same as the Newtonian perturbations to the second order (in all scales), and the pure general relativistic corrections appearing from the third order are numerically negligible (in all scales as well) i...

  6. CERN Relay Race

    CERN Document Server

    CERN Running Club

    2010-01-01

    The CERN relay race will take place around the Meyrin site on Thursday 20 May, starting at 12.15. If possible, please avoid driving on the site during this 20-minute period. If you do meet runners while driving your car, please STOP until they have all passed. Thank you for your cooperation. Details on the route, and how to register your team for the relay race, can be found at: https://espace.cern.ch/Running-Club/CERN-Relay

  7. CERN Relay Race 2009

    CERN Multimedia

    2009-01-01

    The CERN relay race will take place around the Meyrin site on Thursday 14th May starting at 12:15. If possible, please avoid driving on the site during this 20-minute period. If you do meet runners while driving your car, please STOP until they have all passed. Thank you for your cooperation. More details on how to register your team for the relay race

  8. A method to measure the axion mass

    Science.gov (United States)

    Carboni, G.

    1981-05-01

    We have calculated the decay rate of the triplet state of positronium into axion + gamma, under the hypothesis that the axion mass is less than 1 MeV. The branching ratio is found to be ~3 × 10-8. We describe a possible experiment that could detect the axion and measure its mass. On leave from Istituto Nazionale di Fisica Nuclear, Sezione di Pisa, Pisa, Italy.

  9. TT race data logger

    OpenAIRE

    2010-01-01

    This report is made to accomplish the demand from TriCAT Racing motor race team. They suggest if it was possible to create a device capable to log data from a motorbike during a race or testing seasons, mentioning some other similar systems out on the market, but is really expensive. Taking an initial idea, we thought about one way to design a system capable of satisfy the demand of our contractor, trying to reduce costs on the design. At this point we accept the project offered by TriCAT ...

  10. The Cosmophenomenology of Axionic Dark Radiation

    CERN Document Server

    Conlon, Joseph P

    2013-01-01

    Relativistic axions are good candidates for the dark radiation for which there are mounting observational hints. The primordial decays of heavy fields produce axions which are ultra-energetic compared to thermalised matter and inelastic axion-matter scattering can occur with $E_{CoM} \\gg T_{\\gamma}$, thus accessing many interesting processes which are otherwise kinematically forbidden in standard cosmology. Axion-photon scattering into quarks and leptons during BBN affects the light element abundances, and bounds on overproduction of $^4$He constrain a combination of the axion decay constant and the reheating temperature. For supersymmetric models, axion scattering into visible sector superpartners can give direct non-thermal production of dark matter at $T_{\\gamma} \\ll T_{freezeout}$. Most axions --- or any other dark radiation candidate from modulus decay --- still linger today as a Cosmic Axion Background with $E_{axion} \\sim \\mathcal{O}(100) eV$, and a flux of $\\sim 10^6 cm^{-2} s^{-1}$.

  11. Axion induced oscillating electric dipole moments

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Christopher T. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2015-06-24

    In this study, the axion electromagnetic anomaly induces an oscillating electric dipole for any magnetic dipole. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion. The electron will acquire an oscillating electric dipole of frequency ma and strength ~ 10-32 e-cm, within four orders of magnitude of the present standard model DC limit, and two orders of magnitude above the nucleon, assuming standard axion model and dark matter parameters. This may suggest sensitive new experimental venues for the axion dark matter search.

  12. Search for axions at a power reactor

    Energy Technology Data Exchange (ETDEWEB)

    Cavaignac, J.F.; Hoummada, A.; Koang, D.H.; Ost, B.; Vignon, B.; Wilson, R. (Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires); Declais, Y.; Girardi, G.; de Kerret, H.; Pessard, H.

    1983-01-27

    A search has been conducted for the axion at the Bugey reactor which is owned and operated by Electricite de France. The axion production should be proportional to the magnetic transition of np capture, and be detectable by its decay into 2..gamma.. rays. No signal was observed in this measurement. Also no axion signal was seen from a single proton magnetic transition of /sup 97/Nb. Using those two results, the axion can be excluded with a mass up to 1 MeV in the Peccei-Quinn formalism.

  13. R-axion detection at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Hock-Seng; /UC, Berkeley /LBL, Berkeley; Ibe, Masahiro; /SLAC

    2009-06-19

    Supersymmetric models with spontaneously broken approximate R-symmetry contains a light spin 0 particle, the R-axion. The properties of the particle can be a powerful probe of the structure of the new physics. In this paper, we discuss the possibilities of the R-axion detection at the LHC experiments. It is challenge to observe this light particle in the LHC environment. However, for typical values in which the mass of the R-axion is a few hundred MeV, we show that those particles can be detected by searching for displaced vertices from R-axion decay.

  14. Axions as Hot and Cold Dark Matter

    CERN Document Server

    Jeong, Kwang Sik; Takahashi, Fuminobu

    2014-01-01

    The presence of a hot dark matter component has been hinted at 3 sigma by a combination of the results from different cosmological observations. We examine a possibility that pseudo Nambu-Goldstone bosons account for both hot and cold dark matter components. We show that the QCD axions can do the job for the axion decay constant f_a < O(10^10) GeV, if they are produced by the saxion decay and the domain wall annihilation. We also investigate the cases of thermal QCD axions, pseudo Nambu-Goldstone bosons coupled to the standard model sector through the Higgs portal, and axions produced by modulus decay.

  15. Vacuum Selection on Axionic Landscapes

    CERN Document Server

    Wang, Gaoyuan

    2015-01-01

    We compute the distribution of minima that are reached dynamically on multi-field axionic landscapes, both numerically and analytically. Such landscapes are well suited for inflationary model building due to the presence of shift symmetries and possible alignment effects (the KNP mechanism). The resulting distribution of dynamically reached minima differs considerably from the naive expectation based on counting all vacua. These differences are more pronounced in the presence of many fields due to dynamical selection effects: while low lying minima are preferred as fields roll down the potential, trajectories are also more likely to get trapped by one of the many nearby minima. We show that common analytic arguments based on random matrix theory in the large $D$-limit to estimate the distribution of minima are insufficient for quantitative arguments pertaining to the dynamically reached ones. This discrepancy is not restricted to axionic potentials. We provide an empirical expression for the expectation value...

  16. Neutrino-axion-dilaton interconnection

    CERN Document Server

    Bertolini, Stefano; Kolešová, Helena; Malinský, Michal; Vasquez, Juan Carlos

    2016-01-01

    We show that a recently proposed framework that provides a simple connection between Majorana neutrinos and an invisible axion in minimal scalar extensions of the standard electroweak model can be naturally embedded in a classically scale-invariant setup. The explicit breaking of the scale invariance \\`a la Coleman-Weinberg generates the Peccei-Quinn and electroweak scales. The spontaneous breaking of the chiral $U(1)_{PQ}$ triggers the generation of neutrino masses via Type-II seesaw and, at the same time, provides a dynamical solution to the strong CP problem as well as the axion as a dark matter candidate. The electroweak and neutrino mass scales are obtained via a technically natural ultraweak limit of the singlet scalar interactions. Accordingly, a realistic and perturbatively stable scalar spectrum, possibly in the reach of the LHC, is naturally obtained. A very light pseudo-dilaton characterizes such a setting. The vacuum stability of the extended setup is discussed.

  17. Gravitational waves from axion monodromy

    Energy Technology Data Exchange (ETDEWEB)

    Hebecker, Arthur; Jaeckel, Joerg; Rompineve, Fabrizio; Witkowski, Lukas T. [Institute for Theoretical Physics, University of Heidelberg,Philosophenweg 19, 69120 Heidelberg (Germany)

    2016-11-02

    Large field inflation is arguably the simplest and most natural variant of slow-roll inflation. Axion monodromy may be the most promising framework for realising this scenario. As one of its defining features, the long-range polynomial potential possesses short-range, instantonic modulations. These can give rise to a series of local minima in the post-inflationary region of the potential. We show that for certain parameter choices the inflaton populates more than one of these vacua inside a single Hubble patch. This corresponds to a dynamical phase decomposition, analogously to what happens in the course of thermal first-order phase transitions. In the subsequent process of bubble wall collisions, the lowest-lying axionic minimum eventually takes over all space. Our main result is that this violent process sources gravitational waves, very much like in the case of a first-order phase transition. We compute the energy density and peak frequency of the signal, which can lie anywhere in the mHz-GHz range, possibly within reach of next-generation interferometers. We also note that this “dynamical phase decomposition' phenomenon and its gravitational wave signal are more general and may apply to other inflationary or reheating scenarios with axions and modulated potentials.

  18. Vacuum selection on axionic landscapes

    Science.gov (United States)

    Wang, Gaoyuan; Battefeld, Thorsten

    2016-04-01

    We compute the distribution of minima that are reached dynamically on multi-field axionic landscapes, both numerically and analytically. Such landscapes are well suited for inflationary model building due to the presence of shift symmetries and possible alignment effects (the KNP mechanism). The resulting distribution of dynamically reached minima differs considerably from the naive expectation based on counting all vacua. These differences are more pronounced in the presence of many fields due to dynamical selection effects: while low lying minima are preferred as fields roll down the potential, trajectories are also more likely to get trapped by one of the many nearby minima. We show that common analytic arguments based on random matrix theory in the large D-limit to estimate the distribution of minima are insufficient for quantitative arguments pertaining to the dynamically reached ones. This discrepancy is not restricted to axionic potentials. We provide an empirical expression for the expectation value of such dynamically reached minimas' height and argue that the cosmological constant problem is not alleviated in the absence of anthropic arguments. We further comment on the likelihood of inflation on axionic landscapes in the large D-limit.

  19. Gravitational waves from axion monodromy

    Science.gov (United States)

    Hebecker, Arthur; Jaeckel, Joerg; Rompineve, Fabrizio; Witkowski, Lukas T.

    2016-11-01

    Large field inflation is arguably the simplest and most natural variant of slow-roll inflation. Axion monodromy may be the most promising framework for realising this scenario. As one of its defining features, the long-range polynomial potential possesses short-range, instantonic modulations. These can give rise to a series of local minima in the post-inflationary region of the potential. We show that for certain parameter choices the inflaton populates more than one of these vacua inside a single Hubble patch. This corresponds to a dynamical phase decomposition, analogously to what happens in the course of thermal first-order phase transitions. In the subsequent process of bubble wall collisions, the lowest-lying axionic minimum eventually takes over all space. Our main result is that this violent process sources gravitational waves, very much like in the case of a first-order phase transition. We compute the energy density and peak frequency of the signal, which can lie anywhere in the mHz-GHz range, possibly within reach of next-generation interferometers. We also note that this ``dynamical phase decomposition" phenomenon and its gravitational wave signal are more general and may apply to other inflationary or reheating scenarios with axions and modulated potentials.

  20. Axion Landscape and Natural Inflation

    CERN Document Server

    Higaki, Tetsutaro

    2015-01-01

    Multiple axions form a landscape in the presence of various shift symmetry breaking terms. Eternal inflation populates the axion landscape, continuously creating new universes by bubble nucleation. Slow-roll inflation naturally takes place after the tunneling event, because a very flat direction with a super-Planckian decay constant arises due to the alignment mechanism. We study the vacuum structure as well as possible inflationary dynamics in the axion landscape scenario, and find that the inflaton dynamics is given by either natural or multi-natural inflation. In the limit of large decay constant, it is approximated by the quadratic chaotic inflation, which however is disfavored if there is a pressure toward shorter duration of inflation. If the spectral index and the tensor-to-scalar ratio turn out to be different from the quadratic chaotic inflation, there might be observable traces of the bubble nucleation. Also, the existence of small modulations to the inflaton potential is a common feature in the axi...

  1. A search for axions and massive neutrinos

    CERN Multimedia

    2002-01-01

    This experiment relies on the production of a strong, contamination-free (10$ ^{-12} $) source of radioactive $^{125}$I at the ISOLDE facility. Technical developments to achieve the necessary beam intensity are in progress. \\\\ \\\\The possible emission of axions in the 35.5 keV M1 transition of the $^{125}$Te daughter isotope is searched for by the axion analogue of the Mössbauer effect, i.e. the axion resonance absorption in a $^{125}$Te resonance absorber. For this purpose all other radiation emitted from the source is shielded by a non-resonant absorber, which is transparent, however, to axions. The resonance absorption is detected by measurement of subsequently emitted X-rays. A sensitivity to the axion emission branching ratio in the nuclear decay of 10$ ^{-7} $ is strived for.

  2. Oscillating Chiral Tensor Spectrum from Axionic Inflation

    CERN Document Server

    Obata, Ippei

    2016-01-01

    We study the axionic inflation with a modulated potential and examine if the primordial tensor power spectrum exhibits oscillatory feature, which is testable with future space-based gravitational wave experiments such as DECIGO and BBO. In the case of the single-field axion monodromy inflation, it turns out that it is difficult to detect the oscillation in the spectrum due to suppression of the sub-Planckian decay constant of axion. On the other hand, in the case of aligned chromo-natural inflation where the axion is coupled to a SU(2) gauge field, it turns out that the sizable oscillation in the tensor spectrum can occur due to the enhancement of chiral gravitational waves sourced by the gauge field. We expect that this feature will be a new probe to axion phenomenologies in early universe through the chiral gravitational waves.

  3. Fermion production during and after axion inflation

    Energy Technology Data Exchange (ETDEWEB)

    Adshead, Peter; Sfakianakis, Evangelos I. [Department of Physics, University of Illinois at Urbana-Champaign,Urbana, Illinois 61801 (United States)

    2015-11-11

    We study derivatively coupled fermions in axion-driven inflation, specifically m{sub ϕ}{sup 2}ϕ{sup 2} and monodromy inflation, and calculate particle production during the inflationary epoch and the post-inflationary axion oscillations. During inflation, the rolling axion acts as an effective chemical potential for helicity which biases the gravitational production of one fermion helicity over the other. This mechanism allows for efficient gravitational production of heavy fermion states that would otherwise be highly suppressed. Following inflation, the axion oscillates and fermions with both helicities are produced as the effective frequency of the fermion field changes non-adiabatically. For certain values of the fermion mass and axion-fermion coupling strength, the two helicity states are produced asymmetrically, resulting in unequal number-densities of left- and right-helicity fermions.

  4. Axion BEC: A model beyond CDM

    Science.gov (United States)

    Yang, Qiaoli

    I started work on the field of dark matter and cosmology with Dr. Sikivie three years ago with a goal to distinguish observationally axions or axion-like particles (ALPs) from other dark matter candidates such as weakly interacting massive particles (WIMPs) and sterile neutrinos. The subject is exciting because if one can determine the identity of the dark matter, it will be a mile-stone of physics beyond the standard model. On the high energy frontier, the standard model with three generation fermions is firmly established. However, it is not complete because the theory does not contain a plausible dark matter candidate, with properties required from observation, and the theory has fine-tuning problems such as the strong CP problem. On the cosmology and astrophysics frontiers, new observations of the dynamics of galaxy clusters, the rotation curves of galaxies, the abundances of light elements, gravitational lensing, and the anisotropies of the CMBR reach unprecedented accuracy. They imply cold dark matter (CDM) is 23% of the total energy density of the universe. Although many "beyond the standard model" theories may provide proper candidates to serve as CDM particles, the axion is especially compelling because it not only serves as the CDM particle, but also solves the strong CP problem. The axion was initially motivated by the strong CP problem, namely the puzzle why there is no CP violation in the strong interactions. Peccei and Quinn solved the problem by introducing a new UPQ(1) symmetry, and later Weinberg and Wilczek pointed out that the spontaneous breaking of UPQ(1) symmetry leads to a new pseudoscalar particle, the axion[1][2][3]. Axion models were proposed in which the symmetry breaking scale may be much larger than the electroweak scale, in which case the axion is very light and couples extremely weakly to ordinary matter. Furthermore, it was realized [4] that the cold axions, produced by the misalignment mechanism during the QCD phase transition, have

  5. Hydrogen axion star: metallic hydrogen bound to a QCD axion BEC

    Science.gov (United States)

    Bai, Yang; Barger, Vernon; Berger, Joshua

    2016-12-01

    As a cold dark matter candidate, the QCD axion may form Bose-Einstein condensates, called axion stars, with masses around 10-11 M ⊙. In this paper, we point out that a brand new astrophysical object, a Hydrogen Axion Star (HAS), may well be formed by ordinary baryonic matter becoming gravitationally bound to an axion star. We study the properties of the HAS and find that the hydrogen cloud has a high pressure and temperature in the center and is likely in the liquid metallic hydrogen state. Because of the high particle number densities for both the axion star and the hydrogen cloud, the feeble interaction between axion and hydrogen can still generate enough internal power, around 1013 W × ( m a /5 meV)4, to make these objects luminous point sources. High resolution ultraviolet, optical and infrared telescopes can discover HAS via black-body radiation.

  6. Hydrogen Axion Star: Metallic Hydrogen Bound to a QCD Axion BEC

    CERN Document Server

    Bai, Yang; Berger, Joshua

    2016-01-01

    As a cold dark matter candidate, the QCD axion may form Bose-Einstein condensates, called axion stars, with masses around $10^{-11}\\,M_{\\odot}$. In this paper, we point out that a brand new astrophysical object, a Hydrogen Axion Star (HAS), may well be formed by ordinary baryonic matter becoming gravitationally bound to an axion star. We study the properties of the HAS and find that the hydrogen cloud has a high pressure and temperature in the center and is likely in the liquid metallic hydrogen state. Because of the high particle number densities for both the axion star and the hydrogen cloud, the feeble interaction between axion and hydrogen can still generate enough internal power, around $10^{13}~\\mbox{W}\\times(m_a/5~\\mbox{meV})^4$, to make these objects luminous point sources. High resolution ultraviolet, optical and infrared telescopes can discover HAS via black-body radiation.

  7. Flavored axion-monodromy inflation

    Science.gov (United States)

    Ramos, Raymundo

    2016-10-01

    In this talk we consider the breaking of a flavor-symmetric potential as the origin of the pseudo-Goldstone bosons responsible for inflation. The breaking of flavor symmetry generates the fermion mass hierarchy while the breaking of accidental symmetries leads to pseudo-Goldstone bosons with an axion-monodromy potential appropriate for inflation. We deal with models where the inflaton is a linear combination of two fields. We will show that the mechanism by which inflation ends depends on the choice of parameters.

  8. Search for axions with the CDMS experiment.

    Science.gov (United States)

    Ahmed, Z; Akerib, D S; Arrenberg, S; Bailey, C N; Balakishiyeva, D; Baudis, L; Bauer, D A; Beaty, J; Brink, P L; Bruch, T; Bunker, R; Cabrera, B; Caldwell, D O; Cooley, J; Cushman, P; Dejongh, F; Dragowsky, M R; Duong, L; Figueroa-Feliciano, E; Filippini, J; Fritts, M; Golwala, S R; Grant, D R; Hall, J; Hennings-Yeomans, R; Hertel, S; Holmgren, D; Hsu, L; Huber, M E; Kamaev, O; Kiveni, M; Kos, M; Leman, S W; Mahapatra, R; Mandic, V; Moore, D; McCarthy, K A; Mirabolfathi, N; Nelson, H; Ogburn, R W; Pyle, M; Qiu, X; Ramberg, E; Rau, W; Reisetter, A; Saab, T; Sadoulet, B; Sander, J; Schnee, R W; Seitz, D N; Serfass, B; Sundqvist, K M; Tarka, M; Wang, G; Yellin, S; Yoo, J; Young, B A

    2009-10-02

    We report on the first axion search results from the Cryogenic Dark Matter Search (CDMS) experiment at the Soudan Underground Laboratory. An energy threshold of 2 keV for electron-recoil events allows a search for possible solar axion conversion into photons or local galactic axion conversion into electrons in the germanium crystal detectors. The solar axion search sets an upper limit on the Primakov coupling g(agammagamma) of 2.4x10(-9) GeV-1 at the 95% confidence level for an axion mass less than 0.1 keV/c2. This limit benefits from the first precise measurement of the absolute crystal plane orientations in this type of experiment. The galactic axion search analysis sets a world-leading experimental upper limit on the axioelectric coupling g(aee) of 1.4x10(-12) at the 90% confidence level for an axion mass of 2.5 keV/c2.

  9. Axion Induced Oscillating Electric Dipole Moments

    CERN Document Server

    Hill, Christopher T

    2015-01-01

    The axion electromagnetic anomaly induces an oscillating electric dipole for any static magnetic dipole. Static electric dipoles do not produce oscillating magnetic moments. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion. The electron will acquire an oscillating electric dipole of frequency $m_a$ and strength $\\sim 10^{-32}$ e-cm, two orders of magnitude above the nucleon, and within four orders of magnitude of the present standard model DC limit. This may suggest sensitive new experimental venues for the axion dark matter search.

  10. A Model of Visible QCD Axion

    CERN Document Server

    Fukuda, Hajime; Ibe, Masahiro; Yanagida, Tsutomu T

    2015-01-01

    We pursue a class of visible axion models where the axion mass is enhanced by strong dynamics in a mirrored copy of the Standard Model in the line of the idea put forward by Rubakov. In particular, we examine the consistency of the models with laboratory, astrophysical, and cosmological constraints. As a result, viable parameter regions are found, where the mass of the axion is of $O(100)$ MeV or above while the Peccei-Quinn breaking scale is at around $10^{3\\mbox{-}5}$ GeV.

  11. New potentials for string axion inflation

    CERN Document Server

    Kobayashi, Tatsuo; Otsuka, Hajime

    2015-01-01

    We propose a new type of axion inflation with complex structure moduli in the framework of type IIB superstring theory compactified on Calabi-Yau manifold. The inflaton is identified as the axion for the complex structure moduli whose potential is originating from instantonic corrections appearing through the period vector of mirror Calabi-Yau manifold. The axionic shift symmetry is broken down to the discrete one by the inclusion of instantonic correction and certain three-from fluxes. Our proposed inflation scenario is compatible with K\\"ahler moduli stabilization. We also study a typical reheating temperature in the case of complex structure moduli inflation.

  12. X-ray optics for axion helioscopes

    DEFF Research Database (Denmark)

    Jakobsen, Anders Clemen; Pivovaroff, Michael J.; Christensen, Finn Erland

    2013-01-01

    A method of optimizing grazing incidence x-ray coatings in ground based axion helioscopes is presented. Software has been been developed to find the optimum coating when taking both axion spectrum and Micromegas detector quantum efficiency into account. A comparison of the relative effective area...... in the telescope using different multilayer material combinations is produced. Similar methods are used for IAXO, a planned axion helioscope. Additionally, the optimal focal length is modelled while taking into account the least possible background contribution from the detector. © (2013) COPYRIGHT Society...

  13. Gravitational Waves from Axion Monodromy

    CERN Document Server

    Hebecker, Arthur; Rompineve, Fabrizio; Witkowski, Lukas T

    2016-01-01

    Large field inflation is arguably the simplest and most natural variant of slow-roll inflation. Axion monodromy may be the most promising framework for realising this scenario. As one of its defining features, the long-range polynomial potential possesses short-range, instantonic modulations. These can give rise to a series of local minima in the post-inflationary region of the potential. We show that for certain parameter choices the inflaton populates more than one of these vacua inside a single Hubble patch. This corresponds to a dynamical phase decomposition, analogously to what happens in the course of thermal first-order phase transitions. In the subsequent process of bubble wall collisions, the lowest-lying axionic minimum eventually takes over all space. Our main result is that this violent process sources gravitational waves, very much like in the case of a first-order phase transition. We compute the energy density and peak frequency of the signal, which can lie anywhere in the mHz-GHz range, possib...

  14. Imaging Race

    Science.gov (United States)

    Eberhardt, Jennifer L.

    2005-01-01

    Researchers have recently begun to use the tools of neuroscience to examine the social psychological responses associated with race. This article serves as a review of the developing literature in this area. It advances the argument that neuroscience studies of race have the potential to shape fundamental assumptions about race, and the interplay…

  15. CERN Relay Race

    CERN Document Server

    2011-01-01

    The CERN relay race will take place around the Meyrin site on Thursday 19 May starting at 12-15. If possible, please avoid driving on the site during this 20-minute period. If you do meet runners while driving your car, please STOP until they have all passed. Thank you for your cooperation. Details of the course and of how to register your team for the relay race can be found here. Some advice for all runners from the Medical Service can also be found here.   

  16. Nonrelativistic Effective Field Theory for Axions

    CERN Document Server

    Braaten, Eric; Zhang, Hong

    2016-01-01

    Axions can be described by a relativistic field theory with a real scalar field $\\phi$ whose self-interaction potential is a periodic function of $\\phi$. Low-energy axions, such as those produced in the early universe by the vacuum misalignment mechanism, can be described more simply by a nonrelativistic effective field theory with a complex scalar field $\\psi$ whose effective potential is a function of $\\psi^*\\psi$. We determine the coefficients in the expansion of the effective potential to fifth order in $\\psi^*\\psi$ by matching low-energy axion scattering amplitudes. In order to describe a Bose-Einstein condensate of axions that is too dense to expand the effective potential in powers of $\\psi^*\\psi$, we develop a sequence of systematically improvable approximations to the effective potential that include terms of all orders in $\\psi^*\\psi$.

  17. Axions from cosmic string and wall decay

    Energy Technology Data Exchange (ETDEWEB)

    Hagmann, C A

    2010-03-10

    If inflation occurred with a reheat temperature > T{sub PQ}, axions from the decay of global axion strings and domain walls would make an important contribution to the cosmological energy density, comparable to that from vacuum misalignment. Several groups have numerically studied the evolution of axion strings and walls in the past, however substantial uncertainties remain in their contribution to the present density {Omega}{sub a,string+wall} {approx} 1-100 (f{sub a}/10{sup 12} GeV){sup 7/6}, where f{sub a} is the axion decay constant. I will describe the numerical methods used in our simulations and show results for several string and wall configurations.

  18. Axions as hot and cold dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Kwang Sik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kawasaki, Masahiro [Tokyo Univ., Kashiwa (Japan). Inst. for Cosmic Ray Research; Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS; Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS

    2013-10-15

    The presence of a hot dark matter component has been hinted at 3{sigma} by a combination of the results from different cosmological observations. We examine a possibility that pseudo Nambu- Goldstone bosons account for both hot and cold dark matter components. We show that the QCD axions can do the job for the axion decay constant f{sub a}axions, pseudo Nambu-Goldstone bosons coupled to the standard model sector through the Higgs portal, and axions produced by modulus decay.

  19. Nonrelativistic effective field theory for axions

    Science.gov (United States)

    Braaten, Eric; Mohapatra, Abhishek; Zhang, Hong

    2016-10-01

    Axions can be described by a relativistic field theory with a real scalar field ϕ whose self-interaction potential is a periodic function of ϕ . Low-energy axions, such as those produced in the early Universe by the vacuum misalignment mechanism, can be described more simply by a nonrelativistic effective field theory with a complex scalar field ψ whose effective potential is a function of ψ*ψ . We determine the coefficients in the expansion of the effective potential to fifth order in ψ*ψ by matching low-energy axion scattering amplitudes. In order to describe a Bose-Einstein condensate of axions that is too dense to truncate the expansion of the effective potential in powers of ψ*ψ , we develop a sequence of systematically improvable approximations to the effective potential that resum terms of all orders in ψ*ψ .

  20. Nonthermal axion dark radiation and constraints

    Science.gov (United States)

    Mazumdar, Anupam; Qutub, Saleh; Saikawa, Ken'ichi

    2016-09-01

    The Peccei-Quinn mechanism presents a neat solution to the strong C P problem. As a by-product, it provides an ideal dark matter candidate, "the axion", albeit with a tiny mass. Axions therefore can act as dark radiation if excited with large momenta after the end of inflation. Nevertheless, the recent measurement of relativistic degrees of freedom from cosmic microwave background radiation strictly constrains the abundance of such extra relativistic species. We show that ultrarelativistic axions can be abundantly produced if the Peccei-Quinn field was initially displaced from the minimum of the potential. This in lieu places an interesting constraint on the axion dark matter window with large decay constant which is expected to be probed by future experiments. Moreover, an upper bound on the reheating temperature can be placed, which further constrains the thermal history of our Universe.

  1. Dark-matter QCD-axion searches.

    Science.gov (United States)

    Rosenberg, Leslie J

    2015-10-06

    In the late 20th century, cosmology became a precision science. Now, at the beginning of the next century, the parameters describing how our universe evolved from the Big Bang are generally known to a few percent. One key parameter is the total mass density of the universe. Normal matter constitutes only a small fraction of the total mass density. Observations suggest this additional mass, the dark matter, is cold (that is, moving nonrelativistically in the early universe) and interacts feebly if at all with normal matter and radiation. There's no known such elementary particle, so the strong presumption is the dark matter consists of particle relics of a new kind left over from the Big Bang. One of the most important questions in science is the nature of this dark matter. One attractive particle dark-matter candidate is the axion. The axion is a hypothetical elementary particle arising in a simple and elegant extension to the standard model of particle physics that nulls otherwise observable CP-violating effects (where CP is the product of charge reversal C and parity inversion P) in quantum chromo dynamics (QCD). A light axion of mass 10(-(6-3)) eV (the invisible axion) would couple extraordinarily weakly to normal matter and radiation and would therefore be extremely difficult to detect in the laboratory. However, such an axion is a compelling dark-matter candidate and is therefore a target of a number of searches. Compared with other particle dark-matter candidates, the plausible range of axion dark-matter couplings and masses is narrowly constrained. This focused search range allows for definitive searches, where a nonobservation would seriously impugn the dark-matter QCD-axion hypothesis. Axion searches use a wide range of technologies, and the experiment sensitivities are now reaching likely dark-matter axion couplings and masses. This article is a selective overview of the current generation of sensitive axion searches. Not all techniques and experiments

  2. Axionic Band Structure of the Cosmological Constant

    OpenAIRE

    Bachlechner, Thomas C.

    2015-01-01

    We argue that theories with multiple axions generically contain a large number of vacua that can account for the smallness of the cosmological constant. In a theory with N axions, the dominant instantons with charges Q determine the discrete symmetry of vacua. Subleading instantons break the leading periodicity and lift the vacuum degeneracy. For generic integer charges the number of distinct vacua is given by |det(Q)|~exp(N). Our construction motivates the existence of a landscape with a vas...

  3. Gravity wave and model-independent axion

    CERN Document Server

    Kim, Jihn E

    2016-01-01

    In this short comment, we notice that the model-independent axion contribution to the graviton mass at just outside the Schwarzschild radius is completely negligible in GW150914. The model-independent axion contribution to the graviton mass at the order $10^{-22}\\,$eV might be possible for merger of black holes of mass of order $2\\times 10^{14}\\,$kg.

  4. Planckian axions and the Weak Gravity Conjecture

    Science.gov (United States)

    Bachlechner, Thomas C.; Long, Cody; McAllister, Liam

    2016-01-01

    Several recent works [1-3] have claimed that the Weak Gravity Conjecture (WGC) excludes super-Planckian displacements of axion fields, and hence large-field axion inflation, in the absence of monodromy. We argue that in theories with N ≫ 1 axions, super-Planckian axion diameters D are readily allowed by the WGC. We clarify the non-trivial relationship between the kinetic matrix K — unambiguously defined by its form in a Minkowski-reduced basis — and the diameter of the axion fundamental domain, emphasizing that in general the diameter is not solely determined by the eigenvalues f 1 2 ≤ ṡ ṡ ṡ ≤ f N 2 of K: the orientations of the eigenvectors with respect to the identifications imposed by instantons must be incorporated. In particular, even if one were to impose the condition f N M pl does not immediately imply the existence of unsuppressed higher harmonic contributions to the potential. Finally, we argue that in effective axion-gravity theories, the zero-form version of the WGC can be satisfied by gravitational instantons that make negligible contributions to the potential.

  5. Planckian Axions and the Weak Gravity Conjecture

    CERN Document Server

    Bachlechner, Thomas C; McAllister, Liam

    2015-01-01

    Several recent works have claimed that the Weak Gravity Conjecture (WGC) excludes super-Planckian displacements of axion fields, and hence large-field axion inflation, in the absence of monodromy. We argue that in theories with $N\\gg1$ axions, super-Planckian axion diameters $\\cal{D}$ are readily allowed by the WGC. We clarify the nontrivial relationship between the kinetic matrix $K$ --- unambiguously defined by its form in a Minkowski-reduced basis --- and the diameter of the axion fundamental domain, emphasizing that in general the diameter is not solely determined by the eigenvalues $f_1^2 \\le ... \\le f_N^2$ of $K$: the orientations of the eigenvectors with respect to the identifications imposed by instantons must be incorporated. In particular, even if one were to impose the condition $f_NM_{pl}$ does not immediately imply the existence of unsuppressed higher harmonic contributions to the potential. Finally, we argue that in effective axion-gravity theories, the zero-form version of the WGC can be satisf...

  6. Black hole formation from axion stars

    CERN Document Server

    Helfer, Thomas; Clough, Katy; Fairbairn, Malcolm; Lim, Eugene A; Becerril, Ricardo

    2016-01-01

    The classical equations of motion for an axion with potential $V(\\phi)=m_a^2f_a^2 [1-\\cos (\\phi/f_a)]$ possess quasi-stable, localized, oscillating solutions, which we refer to as "axion stars". We study, for the first time, collapse of axion stars numerically using the full non-linear Einstein equations of general relativity and the full non-perturbative cosine potential. We map regions on an "axion star stability diagram", parameterized by the initial ADM mass, $M_{\\rm ADM}$, and axion decay constant, $f_a$. We identify three regions of the parameter space: i) long-lived oscillating axion star solutions, with a base frequency, $m_a$, modulated by self-interactions, ii) collapse to a BH and iii) complete dispersal due to gravitational cooling and interactions. We locate the boundaries of these three regions and an approximate "triple point" $(M_{\\rm TP},f_{\\rm TP})\\sim (2.4 M_{pl}^2/m_a,0.3 M_{pl})$. For $f_a$ below the triple point BH formation proceeds during winding (in the complex $U(1)$ picture) of the ...

  7. Axion response in gapless systems.

    Science.gov (United States)

    Bergman, Doron L

    2011-10-21

    The strong topological insulator in 3D is expected to realize a quantized magnetoelectric response, the so-called axion response. However, many of the materials predicted to be topological insulators have turned out to be metallic, with bulk Fermi surfaces. Following the result of Bergman and Refael [Phys. Rev. B 82, 195417 (2010)] that the surface states of the topological insulator persist even when the band structure gap is closed, we explore the fate of the magnetoelectric response in such systems. We find that a nonquantized magnetoelectric coupling remains once a bulk Fermi surface opens. More generally, we find higher-dimensional analogs of the intrinsic anomalous Hall effect for all Chern forms-quantized transport coefficients in the gapped case become nonquantized when the gap is closed. In particular, the nonquantized magnetoelectric response in 3D descends from the intrinsic anomalous Hall effect analog in 4D.

  8. Conceptual design of the International Axion Observatory (IAXO)

    DEFF Research Database (Denmark)

    Armengaud, E.; Avignone, F. T.; Betz, M.

    2014-01-01

    The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal-to-noise ratio, IAXO...... will be about 4–5 orders of magnitude more sensitive than CAST, currently the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few × 10−12 GeV−1 and thus probing a large fraction of the currently unexplored axion and ALP parameter space. IAXO will also be sensitive...... and ALP research in the next decade. In this paper we present the conceptual design of IAXO, which follows the layout of an enhanced axion helioscope, based on a purpose-built 20 m-long 8-coils toroidal superconducting magnet. All the eight 60cm-diameter magnet bores are equipped with focusing x...

  9. QCD Axion Star Collapse with the Chiral Potential

    Energy Technology Data Exchange (ETDEWEB)

    Eby, Joshua; Leembruggen, Madelyn; Suranyi, Peter; Wijewardhana, L. C.R.

    2017-02-17

    In a previous work, we analyzed collapsing axion stars using the low-energy instanton potential, showing that the total energy is always bounded and that collapsing axion stars do not form black holes. In this paper, we provide a proof that the conclusions are unchanged when using instead the more general chiral potential for QCD axions.

  10. Large-scale search for dark-matter axions

    Energy Technology Data Exchange (ETDEWEB)

    Hagmann, C.A., LLNL; Kinion, D.; Stoeffl, W.; Van Bibber, K.; Daw, E.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States); McBride, J. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Peng, H. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Rosenberg, L.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Xin, H. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Laveigne, J. [Florida Univ., Gainesville, FL (United States); Sikivie, P. [Florida Univ., Gainesville, FL (United States); Sullivan, N.S. [Florida Univ., Gainesville, FL (United States); Tanner, D.B. [Florida Univ., Gainesville, FL (United States); Moltz, D.M. [Lawrence Berkeley Lab., CA (United States); Powell, J. [Lawrence Berkeley Lab., CA (United States); Clarke, J. [Lawrence Berkeley Lab., CA (United States); Nezrick, F.A. [Fermi National Accelerator Lab., Batavia, IL (United States); Turner, M.S. [Fermi National Accelerator Lab., Batavia, IL (United States); Golubev, N.A. [Russian Academy of Sciences, Moscow (Russia); Kravchuk, L.V. [Russian Academy of Sciences, Moscow (Russia)

    1998-01-01

    Early results from a large-scale search for dark matter axions are presented. In this experiment, axions constituting our dark-matter halo may be resonantly converted to monochromatic microwave photons in a high-Q microwave cavity permeated by a strong magnetic field. Sensitivity at the level of one important axion model (KSVZ) has been demonstrated.

  11. Small field axion inflation with sub-Planckian decay constant

    Science.gov (United States)

    Kadota, Kenji; Kobayashi, Tatsuo; Oikawa, Akane; Omoto, Naoya; Otsuka, Hajime; Tatsuishi, Takuya H.

    2016-10-01

    We study an axion inflation model recently proposed within the framework of type IIB superstring theory, where we pay a particular attention to a sub-Planckian axion decay constant. Our axion potential can lead to the small field inflation with a small tensor-to-scalar ratio, and a typical reheating temperature can be as low as GeV.

  12. Small field axion inflation with sub-Planckian decay constant

    CERN Document Server

    Kadota, Kenji; Oikawa, Akane; Omoto, Naoya; Otsuka, Hajime; Tatsuishi, Takuya H

    2016-01-01

    We study an axion inflation model recently proposed within the framework of type IIB superstring theory, where we pay a particular attention to a sub-Planckian axion decay constant. Our axion potential can lead to the small field inflation with a small tensor-to-scalar ratio, and a typical reheating temperature can be as low as GeV.

  13. Universal constraints on axions from inflation

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Ricardo Z.; Sloth, Martin S. [CP-Origins, Center for Cosmology and Particle Physics Phenomenology,University of Southern Denmark, Campusvej 55, 5230 Odense M (Denmark)

    2014-12-19

    We consider the presence of an axion like particle, σ, with a generic CP violating axial coupling of the form (α σ/f)FF-tilde, where F{sub μν} is the gauge field strength of a generic abelian U(1) gauge group, not necessarily associated with the standard electromagnetism, and f is the decay constant of the axion. It has previously been demonstrated that if the axion is identified with the inflaton, such an interaction can lead to measurable cosmological signatures (non-Gaussian modifications of the curvature perturbation spectrum) depending on the parameter ξ=α σ-dot /(fH). In the present paper we will show that the generation of curvature perturbation at horizon crossing due to the axial coupling has a universal form and remains unmodified in terms of the ξ parameter even if the axion, σ, is not identified with the inflaton. As a consequence, it does not appear to be possible to generate CMB tensor perturbations through this mechanism, larger than the vacuum ones, without violating the observational constraints unless we combine this mechanism with a curvaton or if the σ field becomes heavy and decays during inflation. Even in this last case there are non-trivial constraints coming from the slow-roll evolution of the curvature perturbation on super horizon scales which should be taken into account. We also comment on implications for inflationary models where axions play an important role as, for example, models of natural inflation where more than one axion are included and models where the curvaton is an axion.

  14. Windows on the axion. [quantum chromodynamics (QCD)

    Science.gov (United States)

    Turner, Michael S.

    1989-01-01

    Peccei-Quinn symmetry with attendant axion is a most compelling, and perhaps the most minimal, extension of the standard model, as it provides a very elegant solution to the nagging strong CP-problem associated with the theta vacuum structure of QCD. However, particle physics gives little guidance as to the axion mass; a priori, the plausible values span the range: 10(-12)eV is approx. less than m(a) which is approx. less than 10(6)eV, some 18 orders-of-magnitude. Laboratory experiments have excluded masses greater than 10(4)eV, leaving unprobed some 16 orders-of-magnitude. Axions have a host of interesting astrophysical and cosmological effects, including, modifying the evolution of stars of all types (our sun, red giants, white dwarfs, and neutron stars), contributing significantly to the mass density of the Universe today, and producting detectable line radiation through the decays of relic axions. Consideration of these effects has probed 14 orders-of-magnitude in axion mass, and has left open only two windows for further exploration: 10(-6)eV is approx. less than m(a) is approx. less than 10(-3)eV and 1eV is approx. less than m(a) is approx. less than 5eV (hadronic axions only). Both these windows are accessible to experiment, and a variety of very interesting experiments, all of which involve heavenly axions, are being planned or are underway.

  15. CERN Relay Race

    CERN Multimedia

    Running Club

    2010-01-01

    This year’s CERN Relay Race will take place around the Meyrin site on Thursday 20th May at 12h00. This annual event is for teams of 6 runners covering distances of 1000m, 800m, 800m, 500m, 500m and 300m respectively. Teams may be entered in the Seniors, Veterans, Ladies, Mixed or Open categories. The registration fee is 10 CHF per runner, and each runner receives a souvenir prize. As usual, there will be a programme of entertainments from 12h in the arrival area, in front of the Restaurant no. 1. Drinks, food, CERN club information and music will be available for the pleasure of both runners and spectators. The race starts at 12h15, with results and prize giving at 13:15.   For details of the race, and of how to sign up a team, please visit: https://espace.cern.ch/Running-Club/CERN-Relay The event is organised by the CERN Running Club with the support of the CERN Staff Association.  

  16. Flavored Universe dispatched via Axion and Neutrino

    CERN Document Server

    Ahn, Y H

    2016-01-01

    Motivated by the flavored Peccei-Quinn (PQ) symmetry for unifying flavor physics and string theory, we construct an explicit model by introducing an $U(1)$ symmetry as a fundamental one for rather recent but fast growing issues of astro-particle physics and cosmology, in a way that the $U(1)_X$-$[gravity]^2$ anomaly-free condition with the standard model (SM) flavor structure demands additional sterile neutrinos as well as no axionic domain-wall problem, encompassing several main issues connected to each other: leptonic mixings and CP violation in neutrino oscillation, high-energy neutrinos, QCD axion, axion cooling of stars, inflation, cosmological constant, leptogenesis, and dark matter (DM). The QCD axion decay constant, through its connection to the astrophysical constraints of stellar evolution and the SM fermion masses, is shown to be fixed at $F_A=1.30^{+0.66}_{-0.54}\\times10^{9}$ GeV (consequently, its mass $m_a=4.34^{+3.37}_{-1.49}$ meV and axion-photon coupling $|g_{a\\gamma\\gamma}|=1.30^{+1.01}_{-0....

  17. Axion-dilaton cosmology and dark energy

    Energy Technology Data Exchange (ETDEWEB)

    Catena, R.; Moeller, J.

    2007-09-15

    We discuss a class of flat FRW cosmological models based on D=4 axion-dilaton gravity universally coupled to cosmological background fluids. In particular, we investigate the possibility of recurrent acceleration, which was recently shown to be generically realized in a wide class of axion-dilaton models, but in absence of cosmological background fluids. We observe that, once we impose the existence of radiation - and matter - dominated earlier stages of cosmic evolution, the axion-dilaton dynamics is altered significantly with respect to the case of pure axion-dilaton gravity. During the matter dominated epoch the scalar fields remain either frozen, due to the large expansion rate, or enter a cosmological scaling regime. In both cases, oscillations of the effective equation of state around the acceleration boundary value are impossible. Models which enter an oscillatory stage in the low redshift regime, on the other hand, are disfavored by observations. We also comment on the viability of the axion-dilaton system as a candidate for dynamical dark energy. In a certain subclass of models, an intermediate scaling regime is succeeded by eternal acceleration. We also briefly discuss the issue of dependence on initial conditions. (orig.)

  18. Axions and the Galactic Angular Momentum Distribution

    CERN Document Server

    Banik, N

    2013-01-01

    We analyze the behavior of axion dark matter before it falls into a galactic gravitational potential well. The axions thermalize sufficiently fast by gravitational self-interactions that almost all go to their lowest energy state consistent with the total angular momentum acquired from tidal torquing. That state is a state of rigid rotation on the turnaround sphere. It predicts the occurrence and detailed properties of the caustic rings of dark matter for which observational evidence had been found earlier. We show that the vortices in the axion Bose-Einstein condensate (BEC) are attractive, unlike those in superfluid $^4$He and dilute gases. We expect that a large fraction of the vortices in the axion BEC join into a single big vortex along the rotation axis of the galaxy. The resulting enhancement of caustic rings explains the typical size of the rises in the Milky Way rotation curve attributed to caustic rings. We show that baryons and ordinary cold dark matter particles are entrained by the axion BEC and ...

  19. Coupled Boltzmann computation of mixed axion neutralino dark matter in the SUSY DFSZ axion model

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Kyu Jung; Baer, Howard; Serce, Hasan [Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks, Norman, OK 73019 (United States); Lessa, Andre, E-mail: bae@nhn.ou.edu, E-mail: baer@nhn.ou.edu, E-mail: lessa@fma.if.usp.br, E-mail: serce@ou.edu [Instituto de Física, Universidade de São Paulo, São Paulo – SP (Brazil)

    2014-10-01

    The supersymmetrized DFSZ axion model is highly motivated not only because it offers solutions to both the gauge hierarchy and strong CP problems, but also because it provides a solution to the SUSY μ-problem which naturally allows for a Little Hierarchy. We compute the expected mixed axion-neutralino dark matter abundance for the SUSY DFSZ axion model in two benchmark cases—a natural SUSY model with a standard neutralino underabundance (SUA) and an mSUGRA/CMSSM model with a standard overabundance (SOA). Our computation implements coupled Boltzmann equations which track the radiation density along with neutralino, axion, axion CO (produced via coherent oscillations), saxion, saxion CO, axino and gravitino densities. In the SUSY DFSZ model, axions, axinos and saxions go through the process of freeze-in—in contrast to freeze-out or out-of-equilibrium production as in the SUSY KSVZ model—resulting in thermal yields which are largely independent of the re-heat temperature. We find the SUA case with suppressed saxion-axion couplings (ξ=0) only admits solutions for PQ breaking scale f{sub a}∼< 6× 10{sup 12} GeV where the bulk of parameter space tends to be axion-dominated. For SUA with allowed saxion-axion couplings (ξ =1), then f{sub a} values up to ∼ 10{sup 14} GeV are allowed. For the SOA case, almost all of SUSY DFSZ parameter space is disallowed by a combination of overproduction of dark matter, overproduction of dark radiation or violation of BBN constraints. An exception occurs at very large f{sub a}∼ 10{sup 15}–10{sup 16} GeV where large entropy dilution from CO-produced saxions leads to allowed models.

  20. Status of the U.S. Dark Matter Axion Search

    Energy Technology Data Exchange (ETDEWEB)

    Hagmann, C.; Asztalos, S.; Daw, E.; Golubev, N.A.; Kinion, D.; Moltz, D.M.; Nezrick, F.; Peng, H.; Powell, J.; Rosenberg, L.J.; Sikivie, P.; Stoeffl, W.; Sullivan, N.S.; Tanner, D.B.; Turner, M.S.; Van Bibber, K.

    2000-10-04

    We describe the status of a sensitive search for halo axions with masses in the {mu}eV range. A tunable large-volume and low-loss microwave cavity is operated at low temperature in a strong magnetic field. Resonant Primakoff conversion of axions into photons takes place when the cavity frequency is matched to the axion mass. No positive signal has been found so far, and we are able to exclude hadronic axions as the dominant halo component over a significant axion mass range. Future plans for a detector upgrade are outlined.

  1. Bose-Einstein condensation of dark matter axions.

    Science.gov (United States)

    Sikivie, P; Yang, Q

    2009-09-11

    We show that cold dark matter axions thermalize and form a Bose-Einstein condensate (BEC). We obtain the axion state in a homogeneous and isotropic universe, and derive the equations governing small axion perturbations. Because they form a BEC, axions differ from ordinary cold dark matter in the nonlinear regime of structure formation and upon entering the horizon. Axion BEC provides a mechanism for the production of net overall rotation in dark matter halos, and for the alignment of cosmic microwave anisotropy multipoles.

  2. Testing Ultra-Light Dark Matter Axions Using Galaxy Surveys

    Science.gov (United States)

    Trott, Emery; Smith, Tristan L.; Grin, Daniel

    2017-01-01

    The axion is a particle that has been strongly motivated by symmetry arguments in particle physics since the 1970s and has recently become promising in a cosmological context as well. Ultra-light axions are among the candidates for dark matter and would produce a characteristic suppression of the matter power spectrum at high wavenumbers. The strength of this suppression is heavily dependent on both the mass of the axion and on what fraction of the dark matter it constitutes. In this work, we forecast the sensitivity of future galaxy surveys to determine the ultra-light axion abundance at a variety of axion masses, using Fisher-matrix analysis.

  3. Resonantly detecting axion-mediated forces with nuclear magnetic resonance.

    Science.gov (United States)

    Arvanitaki, Asimina; Geraci, Andrew A

    2014-10-17

    We describe a method based on precision magnetometry that can extend the search for axion-mediated spin-dependent forces by several orders of magnitude. By combining techniques used in nuclear magnetic resonance and short-distance tests of gravity, our approach can substantially improve upon current experimental limits set by astrophysics, and probe deep into the theoretically interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to PQ axion decay constants between 10(9) and 10(12) GeV or axion masses between 10(-6) and 10(-3) eV, independent of the cosmic axion abundance.

  4. QCD axion from a higher dimensional gauge field theory.

    Science.gov (United States)

    Choi, Kiwoon

    2004-03-12

    We point out that a QCD axion solving the strong CP problem can arise naturally from a parity-odd gauge field in five-dimensional (5D) orbifold field theory. The required axion coupling to the QCD anomaly comes from the 5D Chern-Simons coupling, and all other unwanted U(1)PQ breaking axion couplings can be avoided naturally by the 5D gauge symmetry and locality. If the fifth dimension is warped, the resulting axion scale is suppressed by a small warp factor compared to the Planck scale, thereby the model can generate naturally an intermediate axion scale fa = 10(10)-10(12) GeV.

  5. Dynamical Axion String, Torsion Defects in Axion Insulator and Weyl Semimetals

    CERN Document Server

    You, Yizhi; Hughes, Taylor L

    2016-01-01

    In this paper, we investigate the theory of dynamical axion string emerging from chiral symmetry breaking in three-dimensional Weyl semimetals. The chiral symmetry is spontaneously broken by a charge density wave (CDW) order which opens an energy gap and converts the Weyl semimetal into an axion insulator. Indeed, the phase fluctuations of the CDW order parameter act as a dynamical axion field $\\theta({\\vec{x}},t)$ and couples to electromagnetic field via $\\mathcal{L}_{\\theta}=\\frac{\\theta(\\vec{x},t)}{32\\pi^2} \\epsilon^{\\sigma\\tau\

  6. Axion bremsstrahlung from collisions of global strings

    CERN Document Server

    Galtsov, D V; Kerner, R

    2003-01-01

    We calculate axion radiation emitted in the collision of two straight global strings. The strings are supposed to be in the unexcited ground state, to be inclined with respect to each other, and to move in parallel planes. Radiation arises when the point of minimal separation between the strings moves faster than light. This effect exhibits a typical Cerenkov nature. Surprisingly, it allows an alternative interpretation as bremsstrahlung under a collision of point charges in 2+1 electrodynamics. This can be demonstrated by suitable world-sheet reparameterizations and dimensional reduction. Cosmological estimates show that our mechanism generates axion production comparable with that from the oscillating string loops and may lead to further restrictions on the axion window.

  7. The CERN axion solar telescope (CAST)

    Energy Technology Data Exchange (ETDEWEB)

    Aalseth, C.E.; Arik, E.; Autiero, D.; Avignone, F.T.; Barth, K.; Bowyer, S.M.; Brauninger, H.; Brodzinski, R.L.; Carmona, J.M.; Cebrian, S.; Celebi, G.; Cetin, S.; Collar, J.I.; Creswick, R.; Delbart, A.; Delattre, M.; DiLella, L.; De Oliveira, R.; Eleftheriadis, Ch.; Erdutan, N.; Fanourakis, G.; Farach, H.A.; Fiorini, C.; Geralis, Th.; Giomataris, I.; Girard, T.A.; Gninenko, S.N.; Golubev, N.A.; Hasinoff, M.; Hoffmann, D.; Irastorza, I.G.; Jacoby, J.; Jeanneau, F.; Knopf, M.A.; Kovzelev, A.V.; Kotthaus, R.; Krcmar, M.; Krecak, Z.; Lakic, B.; Liolios, A.; Ljubicic, A.; Lutz, G.; Longoni, A.; Luzon, G.; Mailov, A.; Matveev, V.A.; Miley, H.S.; Morales, A.; Morales, J.; Mutterer, M.; Nikolaidis, A.; Nussinov, S.; Ortiz, A.; Pitts, W.K.; Placci, A.; Postoev, V.E.; Raffelt, G.G.; Riege, H.; Sampieto, M.; Sarsa, M.; Savvidis, I.; Stipcevic, M.; Thomas, C.W.; Thompson, R.C.; Valco, P.; Villar, J.A.; Villierme, B.; Walckiers, L.; Wilcox, W.; Zachariadou, K.; Zioutas, K

    2002-07-01

    A decommissioned LHC test magnet is being prepared as the CERN Axion Solar Telescope (CAST) experiment. The magnet has a field of 9.6 Tesla and length of 10 meters. It is being mounted on a platform to track the sun over {+-}8 deg. vertically and {+-}45 deg. , horizontally. A sensitivity in axion-photon coupling g{alpha}{gamma}{gamma} < 5 x 10{sup -11}GeV{sup -1} can be reached for m{sub {alpha}} {<=} 10{sup -2}eV, and with a gas filled tube-can reach g{alpha}{gamma}{gamma} {<=} 10{sup -10}GeV{sup -1} for axion masses m{sub {alpha}} < 2eV.

  8. Electric and magnetic energy at axion haloscopes

    Science.gov (United States)

    Ko, B. R.; Themann, H.; Jang, W.; Choi, J.; Kim, D.; Lee, M. J.; Lee, J.; Won, E.; Semertzidis, Y. K.

    2016-12-01

    We review the electro-magnetic energy at axion haloscopes and find that the electric and the corresponding magnetic energy stored in the cavity modes or, equivalently, the mode dependent electric and magnetic form factors are the same regardless of the position of the cavity inside the solenoid. Furthermore, we extend our argument to the cases satisfying ∇→×B→external=0 , where B→external is a static magnetic field provided by a magnet at an axion haloscope. Two typical magnets, solenoidal and toroidal, satisfy ∇→×B→external=0 ; thus, the electric and the corresponding magnetic energy stored in the cavity modes are always the same in both cases. The energy, however, is independent of the position of the cavity in axion haloscopes with a solenoid, and depends on those with a toroidal magnet.

  9. Axionic suppression of plasma wakefield acceleration

    Science.gov (United States)

    Burton, D. A.; Noble, A.; Walton, T. J.

    2016-09-01

    Contemporary attempts to explain the existence of ultra-high energy cosmic rays using plasma-based wakefield acceleration deliberately avoid non-standard model particle physics. However, such proposals exploit some of the most extreme environments in the Universe and it is conceivable that hypothetical particles outside the standard model have significant implications for the effectiveness of the acceleration process. Axions solve the strong CP problem and provide one of the most important candidates for cold dark matter, and their potential significance in the present context should not be overlooked. Our analysis of the field equations describing a plasma augmented with axions uncovers a dramatic axion-induced suppression of the energy gained by a test particle in the wakefield driven by a particle bunch, or an intense pulse of electromagnetic radiation, propagating at ultra-relativistic speeds within the strongest magnetic fields in the Universe.

  10. Axion inflation in F-theory

    Directory of Open Access Journals (Sweden)

    Thomas W. Grimm

    2014-12-01

    Full Text Available We study the dynamics of axion-like fields in F-theory and suggest that they can serve as inflatons in models of natural inflation. The axions arise from harmonic three-forms on the F-theory compactification space and parameterize a complex torus that varies over the geometric moduli space. In particular, this implies that the axion decay constants depend on the complex structure moduli that can be fixed by background fluxes. This might allow tuning them to be super-Planckian in a controlled way and allow for interesting single field inflationary models. We argue that this requires a localization of the three-forms near regions of strong string coupling, analogously to the reasoning that GUT physics requires the use of F-theory. These models can admit a tensor to scalar ratio r>0.1.

  11. Bump in the blue axion isocurvature spectrum

    Science.gov (United States)

    Chung, Daniel J. H.; Upadhye, Amol

    2017-01-01

    Blue axion isocurvature perturbations are both theoretically well motivated and interesting from a detectability perspective. These power spectra generically have a break from the blue region to a flat region. Previous investigations of the power spectra were analytic, which left a gap in the predicted spectrum in the break region due to the nonapplicability of the used analytic techniques. We therefore compute the isocurvature spectrum numerically for an explicit supersymmetric axion model. We find a bump that enhances the isocurvature signal for this class of scenarios. A fitting function of three parameters is constructed that fits the spectrum well for the particular axion model we study. This fitting function should be useful for blue isocurvature signal hunting in data and making experimental sensitivity forecasts.

  12. Solitonic axion condensates modeling dark matter halos

    Energy Technology Data Exchange (ETDEWEB)

    Castañeda Valle, David, E-mail: casvada@gmail.com; Mielke, Eckehard W., E-mail: ekke@xanum.uam.mx

    2013-09-15

    Instead of fluid type dark matter (DM), axion-like scalar fields with a periodic self-interaction or some truncations of it are analyzed as a model of galaxy halos. It is probed if such cold Bose–Einstein type condensates could provide a viable soliton type interpretation of the DM ‘bullets’ observed by means of gravitational lensing in merging galaxy clusters. We study solitary waves for two self-interacting potentials in the relativistic Klein–Gordon equation, mainly in lower dimensions, and visualize the approximately shape-invariant collisions of two ‘lump’ type solitons. -- Highlights: •An axion model of dark matter is considered. •Collision of axion type solitons are studied in a two dimensional toy model. •Relations to dark matter collisions in galaxy clusters are proposed.

  13. Leptogenesis via axion oscillations after inflation

    CERN Document Server

    Kusenko, Alexander; Yanagida, Tsutomu T

    2014-01-01

    The evolution of an axionic field after inflation offers an explanation for the matter-antimatter asymmetry of the universe. During inflation, light scalar fields, including axions expected to arise from string theory and in various field-theoretic models, develop large expectation values. These fields relax to the minima of their effective potentials during or after reheating. An oscillating axion coupled to the electroweak gauge fields generates an effective chemical potential for the fermion number, which, in the presence of lepton number-violating processes, generates a lepton asymmetry that is partly converted to a baryon asymmetry by sphalerons. The observed matter-antimatter asymmetry can be explained in a broad range of parameter values with the reheating temperatures being at least of order 10^12 GeV, and for all right-handed neutrino masses close to the scale of grand unification. Our mechanism is hence complementary to thermal leptogenesis with respect to the range of allowed parameter values.

  14. Cosmological perturbations of axion with a dynamical decay constant

    Science.gov (United States)

    Kobayashi, Takeshi; Takahashi, Fuminobu

    2016-08-01

    A QCD axion with a time-dependent decay constant has been known to be able to accommodate high-scale inflation without producing topological defects or too large isocurvature perturbations on CMB scales. We point out that a dynamical decay constant also has the effect of enhancing the small-scale axion isocurvature perturbations. The enhanced axion perturbations can even exceed the periodicity of the axion potential, and thus lead to the formation of axionic domain walls. Unlike the well-studied axionic walls, the walls produced from the enhanced perturbations are not bounded by cosmic strings, and thus would overclose the universe independently of the number of degenerate vacua along the axion potential.

  15. CAST constraints on the axion-electron coupling

    CERN Document Server

    Barth, K.; Beltran, B.; Bräuninger, H.; Carmona, J.M.; Collar, J.I.; Dafni, T.; Davenport, M.; Di Lella, L.; Eleftheriadis, C.; Englhauser, J.; Fanourakis, G.; Ferrer-Ribas, E.; Fischer, H.; Franz, J.; Friedrich, P.; Galan, J.; Garcia, J.A.; Geralis, T.; Giomataris, I.; Gninenko, S.; Gomez, H.; Hasinoff, M.D.; Heinsius, F.H.; Hoffmann, D.H.H.; Irastorza, I.G.; Jacoby, J.; Jakovcic, K.; Kang, D.; Königsmann, K.; Kotthaus, R.; Kousouris, K.; Krcmar, M.; Kuster, M.; Lakic, B.; Liolios, A.; Ljubicic, A.; Lutz, G.; Luzon, G.; Miller, D.W.; Papaevangelou, T.; Pivovaroff, M.J.; Raffelt, G.; Redondo, J.; Riege, H.; Rodriguez, A.; Ruz, J.; Savvidis, I.; Semertzidis, Y.; Stewart, L.; Van Bibber, K.; Vieira, J.D.; Villar, J.A.; Vogel, J.K.; Walckiers, L.; Zioutas, K.

    2013-01-01

    In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axio-recombination, the "BCA processes." Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling g_ae and axion-photon interaction strength g_ag using the CAST phase-I data (vacuum phase). For m_a < 10 meV/c2 we find g_ag x g_ae< 8.1 x 10^-23 GeV^-1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission.

  16. A Broadband Approach to Axion Dark Matter Detection

    CERN Document Server

    Kahn, Yonatan; Thaler, Jesse

    2016-01-01

    When ultralight axion dark matter encounters a static magnetic field, it sources an effective electric current that follows the magnetic field lines and oscillates at the axion Compton frequency. We propose a new experiment to detect this axion effective current. In the presence of axion dark matter, a large toroidal magnet will act like an oscillating current ring, whose induced magnetic flux can be measured by an external pickup loop inductively coupled to a SQUID magnetometer. We consider both resonant and broadband readout circuits and show that a broadband approach has advantages at small axion masses. We estimate the reach of this design, taking into account the irreducible sources of noise, and demonstrate potential sensitivity to axion dark matter with masses in the range of 10^{-13} eV to 10^{-6} eV, particularly the QCD axion with a GUT-scale decay constant.

  17. Axionic Band Structure of the Cosmological Constant

    CERN Document Server

    Bachlechner, Thomas C

    2015-01-01

    We argue that theories with multiple axions generically contain a large number of vacua that can account for the smallness of the cosmological constant. In a theory with N axions, the dominant instantons with charges Q determine the discrete symmetry of vacua. Subleading instantons break the leading periodicity and lift the vacuum degeneracy. For generic integer charges the number of distinct vacua is given by |det(Q)|~exp(N). Our construction motivates the existence of a landscape with a vast number of vacua in a large class of four-dimensional effective theories.

  18. Axionic band structure of the cosmological constant

    Science.gov (United States)

    Bachlechner, Thomas C.

    2016-01-01

    We argue that theories with multiple axions generically contain a large number of vacua that can account for the smallness of the cosmological constant. In a theory with N axions, the dominant instantons with charges 풬 determine the discrete symmetry of vacua. Subleading instantons break the leading periodicity and lift the vacuum degeneracy. For generic integer charges the number of distinct vacua is given by √{det (풬⊤풬 ) }∝eN. Our construction motivates the existence of a landscape with a vast number of vacua in a large class of four-dimensional effective theories.

  19. CAST begins its search for solar axions.

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    The CERN Axion Solar Telescope (CAST) consists of a prototype LHC dipole magnet with photon detectors at each end. It has started searching for very weakly interacting neutral particles called axions, which should originate in the core of the Sun. Photos 01 02: The telescope, located at Point 8, can move vertically within its wheeled yellow platform, which travels horizontally along tracks in the floor. In this way, the telescope can view the Sun at sunrise through one end (left) and at sunset through the other. Photos 03 04: Sunrise photon detectors at one end of the telescope.

  20. Axion dark matter and cosmological parameters.

    Science.gov (United States)

    Erken, O; Sikivie, P; Tam, H; Yang, Q

    2012-02-10

    We observe that photon cooling after big bang nucleosynthesis but before recombination can remove the conflict between the observed and theoretically predicted value of the primordial abundance of ^{7}Li. Such cooling is ordinarily difficult to achieve. However, the recent realization that dark matter axions form a Bose-Einstein condensate provides a possible mechanism because the much colder axions may reach thermal contact with the photons. This proposal predicts a high effective number of neutrinos as measured by the cosmic microwave anisotropy spectrum.

  1. Conceptual Design of the International Axion Observatory (IAXO)

    CERN Document Server

    Armengaud, E; Betz, M; Brax, P; Brun, P; Cantatore, G; Carmona, J M; Carosi, G P; Caspers, F; Caspi, S; Cetin, S A; Chelouche, D; Christensen, F E; Dael, A; Dafni, T; Davenport, M; Derbin, A V; Desch, K; Diago, A; Döbrich, B; Dratchnev, I; Dudarev, A; Eleftheriadis, C; Fanourakis, G; Ferrer-Ribas, E; Galán, J; García, J A; Garza, J G; Geralis, T; Gimeno, B; Giomataris, I; Gninenko, S; Gómez, H; González-Díaz, D; Guendelman, E; Hailey, C J; Hiramatsu, T; Hoffmann, D H H; Horns, D; Iguaz, F J; Irastorza, I G; Isern, J; Imai, K; Jakobsen, A C; Jaeckel, J; Jakovčić, K; Kaminski, J; Kawasaki, M; Karuza, M; Krčmar, M; Kousouris, K; Krieger, C; Lakić, B; Limousin, O; Lindner, A; Liolios, A; Luzón, G; Matsuki, S; Muratova, V N; Nones, C; Ortega, I; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Redondo, J; Ringwald, A; Russenschuck, S; Ruz, J; Saikawa, K; Savvidis, I; Sekiguchi, T; Semertzidis, Y K; Shilon, I; Sikivie, P; Silva, H; Kate, H ten; Tomas, A; Troitsky, S; Vafeiadis, T; Bibber, K van; Vedrine, P; Villar, J A; Vogel, J K; Walckiers, L; Weltman, A; Wester, W; Yildiz, S C; Zioutas, K

    2014-01-01

    The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal-to-noise ratio, IAXO will be about 4-5 orders of magnitude more sensitive than CAST, currently the most powerful axion helioscope, reaching sensitivity to axion-photon couplings down to a few $\\times 10^{-12}$ GeV$^{-1}$ and thus probing a large fraction of the currently unexplored axion and ALP parameter space. IAXO will also be sensitive to solar axions produced by mechanisms mediated by the axion-electron coupling $g_{ae}$ with sensitivity $-$for the first time$-$ to values of $g_{ae}$ not previously excluded by astrophysics. With several other possible physics cases, IAXO has the potential to serve as a multi-purpose facility for generic axion and ALP research in the next decade. In this paper we present the conceptual design of IAXO, w...

  2. Axion Models with High Scale Inflation

    CERN Document Server

    Moroi, Takeo; Nakayama, Kazunori; Takimoto, Masahiro

    2014-01-01

    We revisit the cosmological aspects of axion models. In the high-scale inflation scenario, the Peccei-Quinn (PQ) symmetry is likely to be restored during/after inflation. If the curvature of the PQ scalar potential at the origin is smaller than its vacuum expectation value; for instance in a class of SUSY axion models, thermal inflation happens before the radial component of the PQ scalar (saxion) relaxes into the global minimum of the potential and the decay of saxion coherent oscillation would produce too much axion dark radiation. In this paper, we study how to avoid the overproduction of axion dark radiation with some concrete examples. We show that, by taking account of the finite-temperature dissipation effect appropriately, the overproduction constraint can be relaxed since the PQ scalar can take part in the thermal plasma again even after the PQ phase transition. We also show that it can be further relaxed owing to the late time decay of another heavy CP-odd scalar, if it is present.

  3. Axion hot dark matter bounds after Planck

    Energy Technology Data Exchange (ETDEWEB)

    Archidiacono, Maria; Hannestad, Steen [Department of Physics and Astronomy, University of Aarhus DK-8000 Aarhus C (Denmark); Mirizzi, Alessandro [II. Institut für Theoretische Physik, Universität Hamburg Luruper Chaussee 149, D-22761 Hamburg (Germany); Raffelt, Georg [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut) Föhringer Ring 6, D-80805 München (Germany); Wong, Yvonne Y.Y., E-mail: archi@phys.au.dk, E-mail: sth@phys.au.dk, E-mail: alessandro.mirizzi@desy.de, E-mail: raffelt@mpp.mpg.de, E-mail: yvonne.y.wong@unsw.edu.au [School of Physics, The University of New South Wales Sydney NSW 2052 (Australia)

    2013-10-01

    We use cosmological observations in the post-Planck era to derive limits on thermally produced cosmological axions. In the early universe such axions contribute to the radiation density and later to the hot dark matter fraction. We find an upper limit m{sub a} < 0.67 eV at 95% C.L. after marginalising over the unknown neutrino masses, using CMB temperature and polarisation data from Planck and WMAP respectively, the halo matter power spectrum extracted from SDSS-DR7, and the local Hubble expansion rate H{sub 0} released by the Carnegie Hubble Program based on a recalibration of the Hubble Space Telescope Key Project sample. Leaving out the local H{sub 0} measurement relaxes the limit somewhat to 0.86 eV, while Planck+WMAP alone constrain the axion mass to 1.01 eV, the first time an upper limit on m{sub a} has been obtained from CMB data alone. Our axion limit is therefore not very sensitive to the tension between the Planck-inferred H{sub 0} and the locally measured value. This is in contrast with the upper limit on the neutrino mass sum, which we find here to range from Σ m{sub ν} < 0.27 eV at 95% C.L. combining all of the aforementioned observations, to 0.84 eV from CMB data alone.

  4. Bounds on hadronic axions from stellar evolution

    Science.gov (United States)

    Raffelt, Georg G.; Dearborn, David S. P.

    1987-10-01

    We consider in detail the effect of the emission of ``hadronic'' invisible axions (which do not couple to electrons) from the interior of stars on stellar evolution. To this end we calculate plasma emission rates for axions due to the Primakoff process for the full range of conditions encountered in a giant star. Much attention is paid to plasma, degeneracy, and screening effects. We reconsider the solar bound by evolving a 1.0 Msolar star to solar age and lowering the presolar helium abundance so as to obtain the correct present-day luminosity of the Sun. The previous bound on the axion-photon coupling of G9cluster M67 and with the value 1.3×108 yr derived from the number of such stars in the old galactic disk population. We obtain a conservative limit of G9decay and probably the possibility of measuring the solar hadronic axion flux which, according to our bounds, must be less than 2×10-3 of the solar luminosity. There remains a narrow range of parameters (0.01<~G9<~0.1, ma<~10-4 eV) in which a recently proposed laboratory experiment might still measure axionlike particles.

  5. The pooltable analogy to axion physics

    Energy Technology Data Exchange (ETDEWEB)

    Sikivie, P.

    1996-01-01

    An imaginary character named TSP finds himself in a playroom whose floor is tilted to one side. However, the pooltable in the playroom is horizontal. TSP wonders how this can be. In doing so, he embarks upon an intellectual journey which parallels that which has been travelled during the past two decades by physicists interested in the Strong CP Problem and axion physics.

  6. The cern axion solar telescope (CAST)

    Energy Technology Data Exchange (ETDEWEB)

    Aalseth, C. E.; Arik, E.; Autiero, D.; Avignone, F. T.; Barth, K.; Bowyer, S. M.; Brauninger, H.; Brodzinski, R. L.; Carmona, J. M.; Cebrian, S.; Celebi, G.; Cetin, S.; Collar, J. I.; Creswick, R.; Delbart, A.; Delattre, M.; DiLella, L.; De Oliveira, R.; Eleftheriadis, Ch.; Erdutan, N.; Fanourakis, G.; Farach, H. A.; Fiorini, C.; Geralis, Th.; Giomataris, I.; Girard, T. A.; Gninenko, S. N.; Golubev, N. A.; Hasinoff, M.; Hoffmann, D.; Irastorza, I. G.; Jacoby, J.; Jeanneau, F.; Knopf, M. A.; Kovzelev, A. V.; Kotthaus, R.; Krčmar, M.; Krečak, Z.; Lakić, B.; Liolios, A.; Ljubičić, A.; Lutz, G.; Longoni, A.; Luzon, G.; Mailov, A.; Matveev, V. A.; Miley, H. S.; Morales, A.; Morales, J.; Mutterer, M.; Nikolaidis, A.; Nussinov, S.; Ortiz, A.; Pitts, W. K.; Placci, A.; Postoev, V. E.; Raffelt, G. G.; Riege, H.; Sampieto, M.; Sarsa, M.; Savvidis, I.; Stipčević, M.; Thomas, C. W.; Thompson, R. C.; Valco, P.; Villar, J. A.; Villierme, B.; Walckiers, L.; Wilcox, W.; Zachariadou, K.; Zioutas, K.

    2002-07-01

    A decommissioned LHC test magnet is being prepared as the CERN Axion Solar Telescope (CAST) experiment. The magnet has a field of 9.6 Tesla and length of 10 meters. It is being mounted on a platform to track the sun over plus or minus 8 to the sixth power vertically and plus or minus 45 to the sixth power, horizontally.

  7. Cosmic strings in axionic-dilatonic gravity

    Science.gov (United States)

    Santos, Caroline

    2001-05-01

    We first consider local cosmic strings in dilaton-axion gravity and show that they are singular solutions. Then we take a supermassive Higgs limit and present expressions for the fields at far distances from the core by applying a Pecci-Quinn and a duality transformation to the dilatonic Melvin's magnetic universe.

  8. Cosmic strings in axionic-dilatonic gravity

    CERN Document Server

    Santos, C

    2001-01-01

    We first consider local cosmic strings in dilaton-axion gravity and show that they are singular solutions. Then we take a supermassive Higgs limit and present expressions for the fields at far distances from the core by applying a Pecci-Quinn and a duality transformation to the dilatonic Melvin's magnetic universe.

  9. Gauge Invariance for the Massive Axion

    CERN Document Server

    Arias, P J; Arias, Pio Jose; Khoudeir, Adel

    1997-01-01

    A massive gauge invariant formulation for scalar ($\\phi$) and antisymmetric ($C_{mnp}$) fields with a topological coupling, which provides a mass for the axion field, is considered. The dual and local equivalence with the non-gauge invariant proposal is established, but on manifolds with non-trivial topological structure both formulations are not globally equivalent.

  10. Axions and the white dwarf luminosity function

    CERN Document Server

    Isern, J; García-Berro, E; Torres, S

    2008-01-01

    The evolution of white dwarfs can be described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision their luminosity function, that is, the number of stars per unit volume and luminosity interval. Since the shape of the bright branch of this function is only sensitive to the average cooling rate, we use this property to check the possible existence of axions, a proposed but not yet detected weakly interacting particle. We show here that the inclusion of the axion emissivity in the evolutionary models of white dwarfs noticeably improves the agreement between the theoretical calculations and the observational white dwarf luminosity function, thus providing the first positive indication that axions could exist. Our results indicate that the best fit is obtained for m_a cos^2beta ~ 2-6 meV, where m_a is the mass of the axion and cos^2beta is a free parameter, and that values larger than 10 meV are clearly excluded.

  11. Axion stabilization in type IIB flux compactifications

    NARCIS (Netherlands)

    Hristov, K.

    2009-01-01

    A scenario for stabilization of axionic moduli fields in the context of type IIB Calabi-Yau flux compactifications is discussed in detail. We consider the case of a Calabi-Yau orientifold with h1,1−≠0 which allows for the presence of B2 and C2-moduli. In an attempt to generalize the KKLT and the Lar

  12. Axion Dark Matter Detection with Cold Molecules

    CERN Document Server

    Graham, Peter W

    2011-01-01

    Current techniques cannot detect axion dark matter over much of its parameter space, particularly in the theoretically well-motivated region where the axion decay constant f_a lies near the GUT and Planck scales. We suggest a novel experimental method to search for QCD axion dark matter in this region. The axion field oscillates at a frequency equal to its mass when it is a component of dark matter. These oscillations induce time varying CP-odd nuclear moments, such as electric dipole and Schiff moments. The coupling between internal atomic fields and these nuclear moments gives rise to time varying shifts to atomic energy levels. These effects can be enhanced by using elements with large Schiff moments such as the light Actinides, and states with large spontaneous parity violation, such as molecules in a background electric field. The energy level shift in such a molecule can be ~ 10^-24 eV or larger. While challenging, this energy shift may be observable in a molecular clock configuration with technology pr...

  13. New confining force solution of the QCD axion domain-wall problem.

    Science.gov (United States)

    Barr, S M; Kim, Jihn E

    2014-12-12

    The serious cosmological problems created by the axion-string-axion-domain-wall system in standard axion models are alleviated by positing the existence of a new confining force. The instantons of this force can generate an axion potential that erases the axion strings long before QCD effects become important, thus preventing QCD-generated axion walls from ever appearing. Axion walls generated by the new confining force would decay so early as not to contribute significantly to the energy in axion dark matter.

  14. Direct detection of dark matter axions with directional sensitivity

    CERN Document Server

    Irastorza, Igor G

    2012-01-01

    We study the directional effect of the expected axion dark matter signal in a resonant cavity of an axion haloscope detector, for cavity geometries not satisfying the condition that the axion de Broglie wavelength is much larger than the cavity dimensions. We focus on long thin cavities immersed in dipole magnets and find, for appropriately chosen cavity lengths, an O(1) modulation of the signal with the cavity orientation with respect the momentum distribution of the relic axion background predicted by the isothermal sphere model for the galactic dark matter halo. This effect can be exploited to design directional axion dark matter detectors, providing an unmistakable signature of the extraterrestrial origin of a possible positive detection. Moreover, the precise shape of the modulation may give information of the galactic halo distribution and, for specific halo models, give extra sensitivity for higher axion masses.

  15. Broadband and Resonant Approaches to Axion Dark Matter Detection.

    Science.gov (United States)

    Kahn, Yonatan; Safdi, Benjamin R; Thaler, Jesse

    2016-09-30

    When ultralight axion dark matter encounters a static magnetic field, it sources an effective electric current that follows the magnetic field lines and oscillates at the axion Compton frequency. We propose a new experiment to detect this axion effective current. In the presence of axion dark matter, a large toroidal magnet will act like an oscillating current ring, whose induced magnetic flux can be measured by an external pickup loop inductively coupled to a SQUID magnetometer. We consider both resonant and broadband readout circuits and show that a broadband approach has advantages at small axion masses. We estimate the reach of this design, taking into account the irreducible sources of noise, and demonstrate potential sensitivity to axionlike dark matter with masses in the range of 10^{-14}-10^{-6}  eV. In particular, both the broadband and resonant strategies can probe the QCD axion with a GUT-scale decay constant.

  16. Broadband and Resonant Approaches to Axion Dark Matter Detection

    Science.gov (United States)

    Kahn, Yonatan; Safdi, Benjamin R.; Thaler, Jesse

    2016-09-01

    When ultralight axion dark matter encounters a static magnetic field, it sources an effective electric current that follows the magnetic field lines and oscillates at the axion Compton frequency. We propose a new experiment to detect this axion effective current. In the presence of axion dark matter, a large toroidal magnet will act like an oscillating current ring, whose induced magnetic flux can be measured by an external pickup loop inductively coupled to a SQUID magnetometer. We consider both resonant and broadband readout circuits and show that a broadband approach has advantages at small axion masses. We estimate the reach of this design, taking into account the irreducible sources of noise, and demonstrate potential sensitivity to axionlike dark matter with masses in the range of 10-14-10-6 e V . In particular, both the broadband and resonant strategies can probe the QCD axion with a GUT-scale decay constant.

  17. Ehlers-harrison-type transformations in dilaton-axion gravity

    CERN Document Server

    Galtsov, D V

    1994-01-01

    The ten--parametric internal symmetry group is found in the D=4 Einstein--Maxwell--Dilaton--Axion theory restricted to space--times admitting a Killing vector field. The group includes dilaton--axion SL(2,R) duality and Harrison--type transformations which are similar to some target--space duality boosts, but act on a different set of variables. New symmetry is used to derive a seven--parametric family of rotating dilaton--axion Taub--NUT dyons.

  18. Collisions of Dark Matter Axion Stars with Astrophysical Sources

    Energy Technology Data Exchange (ETDEWEB)

    Eby, Joshua [Fermilab; Leembruggen, Madelyn [Cincinnati U.; Leeney, Joseph [Cincinnati U.; Suranyi, Peter [Cincinnati U.; Wijewardhana, L. C.R. [Cincinnati U.

    2017-01-05

    If QCD axions form a large fraction of the total mass of dark matter, then axion stars could be very abundant in galaxies. As a result, collisions with each other, and with other astrophysical bodies, can occur. We calculate the rate and analyze the consequences of three classes of collisions, those occurring between a dilute axion star and: another dilute axion star, an ordinary star, or a neutron star. In all cases we attempt to quantify the most important astrophysical uncertainties; we also pay particular attention to scenarios in which collisions lead to collapse of otherwise stable axion stars, and possible subsequent decay through number changing interactions. Collisions between two axion stars can occur with a high total rate, but the low relative velocity required for collapse to occur leads to a very low total rate of collapses. On the other hand, collisions between an axion star and an ordinary star have a large rate, $\\Gamma_\\odot \\sim 3000$ collisions/year/galaxy, and for sufficiently heavy axion stars, it is plausible that most or all such collisions lead to collapse. We identify in this case a parameter space which has a stable region and a region in which collision triggers collapse, which depend on the axion number ($N$) in the axion star, and a ratio of mass to radius cubed characterizing the ordinary star ($M_s/R_s^3$). Finally, we revisit the calculation of collision rates between axion stars and neutron stars, improving on previous estimates by taking cylindrical symmetry of the neutron star distribution into account. Collapse and subsequent decay through collision processes, if occurring with a significant rate, can affect dark matter phenomenology and the axion star mass distribution.

  19. Cosmologically safe QCD axion as a present from extra dimension

    Directory of Open Access Journals (Sweden)

    Masahiro Kawasaki

    2015-11-01

    Full Text Available We propose a QCD axion model where the origin of PQ symmetry and suppression of axion isocurvature perturbations are explained by introducing an extra dimension. Each extra quark–antiquark pair lives on branes separately to suppress PQ breaking operators. The size of the extra dimension changes after inflation due to an interaction between inflaton and a bulk scalar field, which implies that the PQ symmetry can be drastically broken during inflation to suppress undesirable axion isocurvature fluctuations.

  20. Cosmologically safe QCD axion as a present from extra dimension

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Masahiro [Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Yamada, Masaki, E-mail: yamadam@icrr.u-tokyo.ac.jp [Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa, Chiba 277-8582 (Japan); Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Yanagida, Tsutomu T. [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan)

    2015-11-12

    We propose a QCD axion model where the origin of PQ symmetry and suppression of axion isocurvature perturbations are explained by introducing an extra dimension. Each extra quark–antiquark pair lives on branes separately to suppress PQ breaking operators. The size of the extra dimension changes after inflation due to an interaction between inflaton and a bulk scalar field, which implies that the PQ symmetry can be drastically broken during inflation to suppress undesirable axion isocurvature fluctuations.

  1. A Search for Axions by Nuclear Resonance Scattering

    CERN Multimedia

    2002-01-01

    Experimental efforts to prove the existence of an axion - a light neutral pseudoscalar boson predicted theoretically from a solution of the CP conservation problem - have failed so far. The most stringent laboratory limit on the axion mass $ m _{a} $ $<$20 keV makes a search by the axion analog to the Moessbauer effect, which is restricted to $ m _{a} $ $\\leq$100 keV, an attractive possibility. We conduct an experiment utilizing a strong high-purity source of $^1

  2. Limits on axion-photon coupling or on local axion density: Dependence on models of the Milky Way's dark halo

    Science.gov (United States)

    Sloan, J. V.; Hotz, M.; Boutan, C.; Bradley, R.; Carosi, G.; Carter, D.; Clarke, J.; Crisosto, N.; Daw, E. J.; Gleason, J.; Hoskins, J.; Khatiwada, R.; Lyapustin, D.; Malagon, A.; O'Kelley, S.; Ottens, R. S.; Rosenberg, L. J.; Rybka, G.; Stern, I.; Sullivan, N. S.; Tanner, D. B.; van Bibber, K.; Wagner, A.; Will, D.

    2016-12-01

    The μeV-scale axion is a compelling cold dark matter candidate. The Axion Dark Matter eXperiment (ADMX) searches for axions by stimulating the decay of galactic dark matter halo axions into detectable microwave photons by their conversion in a resonant cavity permeated by a strong, static magnetic field. The signal depends on properties of the Milky Way's dark matter halo; the choice of halo model has significant implications for the sensitivity of direct detection searches, e.g., ADMX. This paper explores the sensitivity of the data taken by ADMX from 2008 to 2010 to various dark matter halo models. New models for the phase-space distribution of local axions are considered; the analysis demonstrates that certain assumptions about the dark matter halo improve limits on axion-photon coupling. In addition, new ADMX data covering 860-892 MHz are included in the analysis.

  3. High and low mass Axion Haloscopes at UWA

    CERN Document Server

    McAllister, Ben T; Ivanov, Eugene N; Tobar, Michael E

    2016-01-01

    We consider the design of a haloscope experiment (ORGAN) to probe for axions at 26.6 GHz. The motivation for this search is to perform the first direct test of a result which claims a possible axion signal at this frequency. There are many technical issues and optimisations that must be considered in the design of a high mass axion haloscope. We discuss the current status of the ORGAN experiment, as well as its future. We also discuss low mass axion haloscopes employing lumped 3D LC resonators.

  4. Axion star collisions with Neutron stars and Fast Radio Bursts

    CERN Document Server

    Raby, Stuart

    2016-01-01

    Axions may make a significant contribution to the dark matter of the universe. It has been suggested that these dark matter axions may condense into localized clumps, called "axion stars." In this paper we argue that collisions of dilute axion stars with neutron stars may be the origin of most of the observed fast radio bursts. This idea is a variation of an idea originally proposed by Iwazaki. However, instead of the surface effect of Iwazaki, we propose a perhaps stronger volume effect caused by the induced time dependent electric dipole moment of neutrons.

  5. Axion cold dark matter in view of BICEP2 results.

    Science.gov (United States)

    Gondolo, Paolo; Visinelli, Luca

    2014-07-04

    The properties of axions that constitute 100% of cold dark matter (CDM) depend on the tensor-to-scalar ratio r at the end of inflation. If r=0.20(-0.05)(+0.07) as reported by the BICEP2 Collaboration, then "half" of the CDM axion parameter space is ruled out. Namely, in the context of single-field slow-roll inflation, for axions to be 100% of the CDM, the Peccei-Quinn symmetry must be broken after the end of inflation, so that axion nonadiabatic primordial fluctuations are compatible with observational constraints. The cosmic axion density is then independent of the tensor-to-scalar ratio r, and the axion mass is expected to be in a narrow range that, however, depends on the cosmological model before primordial nucleosynthesis. In the standard Lambda CDM cosmology, the CDM axion mass range is ma=(71±2  μeV)(αdec+1)6/7, where αdec is the fractional contribution to the cosmic axion density from decays of axionic strings and walls.

  6. Constraining axion dark matter with Big Bang Nucleosynthesis

    Directory of Open Access Journals (Sweden)

    Kfir Blum

    2014-10-01

    Full Text Available We show that Big Bang Nucleosynthesis (BBN significantly constrains axion-like dark matter. The axion acts like an oscillating QCD θ angle that redshifts in the early Universe, increasing the neutron–proton mass difference at neutron freeze-out. An axion-like particle that couples too strongly to QCD results in the underproduction of He4 during BBN and is thus excluded. The BBN bound overlaps with much of the parameter space that would be covered by proposed searches for a time-varying neutron EDM. The QCD axion does not couple strongly enough to affect BBN.

  7. Axion star collisions with neutron stars and fast radio bursts

    Science.gov (United States)

    Raby, Stuart

    2016-11-01

    Axions may make a significant contribution to the dark matter of the Universe. It has been suggested that these dark matter axions may condense into localized clumps, called "axion stars." In this paper we argue that collisions of dilute axion stars with neutron stars, of the type known as "magnetars," may be the origin of most of the observed fast radio bursts. This idea is a variation of an idea originally proposed by Iwazaki. However, instead of the surface effect of Iwazaki, we propose a perhaps stronger volume effect caused by the induced time dependent electric dipole moment of neutrons.

  8. Limits to the radiative decay of the axion

    Science.gov (United States)

    Ressell, M. Ted

    1991-01-01

    An axion with a mass greater than 1 eV should be detectable through its decay into two photons. The astrophysical and cosmological limits which define a small window of allowed axion mass above 3 eV are discussed. A firm upper bound to the axion's mass of M(sub a) less than or equal to 8 eV is derived by considering the effect of decaying axions upon the diffuse extragalactic background radiation and the brightness of the night sky due to axions in the halo of the Milky Way galaxy. The intergalactic light of clusters of galaxies is shown to be an ideal place to search for an emission line arising from the radiative decay of axions. An unsuccessful search for this emission line in three clusters of galaxies is then detailed. Limits to the presence of any intracluster line emission are derived with the result that axions with masses between 3 and 8 eV are excluded by the data, effectively closing this window of axion mass, unless a severe cancellation of axionic decay amplitudes occurs. The intracluster flux limits are then used to constrain the amplitude of any such model dependence.

  9. STAX. An Axion-like Particle Search with Microwave Photons

    CERN Document Server

    Ferretti, J

    2016-01-01

    We discuss an improved detection scheme for a light-shining-through-wall (LSW) experiment for axion-like particle searches. We propose to use: gyrotrons or klystrons, which can provide extremely intense photon fluxes at frequencies around 30 GHz; transition-edge-sensors (TES) single photon detectors in this frequency domain, with efficiency $\\approx1$; high quality factor Fabry-Perot cavities in the microwave domain, both on the photon-axion conversion and photon regeneration sides. We compute that present laboratory exclusion limits on axion-like particles might be improved by at least four orders of magnitude for axion masses $\\lesssim 0.02$ meV.

  10. First results from the CERN axion solar telescope.

    Science.gov (United States)

    Zioutas, K; Andriamonje, S; Arsov, V; Aune, S; Autiero, D; Avignone, F T; Barth, K; Belov, A; Beltrán, B; Bräuninger, H; Carmona, J M; Cebrián, S; Chesi, E; Collar, J I; Creswick, R; Dafni, T; Davenport, M; Di Lella, L; Eleftheriadis, C; Englhauser, J; Fanourakis, G; Farach, H; Ferrer, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, I; Gninenko, S; Goloubev, N; Hasinoff, M D; Heinsius, F H; Hoffmann, D H H; Irastorza, I G; Jacoby, J; Kang, D; Königsmann, K; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Lakić, B; Lasseur, C; Liolios, A; Ljubicić, A; Lutz, G; Luzón, G; Miller, D W; Morales, A; Morales, J; Mutterer, M; Nikolaidis, A; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, G; Ruz, J; Riege, H; Sarsa, M L; Savvidis, I; Serber, W; Serpico, P; Semertzidis, Y; Stewart, L; Vieira, J D; Villar, J; Walckiers, L; Zachariadou, K

    2005-04-01

    Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)axion masses.

  11. On the possibility of large axion moduli spaces

    Energy Technology Data Exchange (ETDEWEB)

    Rudelius, Tom [Jefferson Physical Laboratory, Harvard University,Cambridge, MA 02138 (United States)

    2015-04-28

    We study the diameters of axion moduli spaces, focusing primarily on type IIB compactifications on Calabi-Yau three-folds. In this case, we derive a stringent bound on the diameter in the large volume region of parameter space for Calabi-Yaus with simplicial Kähler cone. This bound can be violated by Calabi-Yaus with non-simplicial Kähler cones, but additional contributions are introduced to the effective action which can restrict the field range accessible to the axions. We perform a statistical analysis of simulated moduli spaces, finding in all cases that these additional contributions restrict the diameter so that these moduli spaces are no more likely to yield successful inflation than those with simplicial Kähler cone or with far fewer axions. Further heuristic arguments for axions in other corners of the duality web suggest that the difficulty observed in http://dx.doi.org/10.1088/1475-7516/2003/06/001 of finding an axion decay constant parametrically larger than M{sub p} applies not only to individual axions, but to the diagonals of axion moduli space as well. This observation is shown to follow from the weak gravity conjecture of http://dx.doi.org/10.1088/1126-6708/2007/06/060, so it likely applies not only to axions in string theory, but also to axions in any consistent theory of quantum gravity.

  12. Results on axion physics from the CAST Experiment at CERN

    CERN Document Server

    Eleftheriadis, Christos A; Aune, S; Barth, K; Belov, A; Beltran, B; Bräuninger, H; Carmona, J; Cebrián, S; Collar, J I; Dafni, T; Davenport, M; Di Lella, L; Englhauser, J; Fanourakis, G K; Ferrer-Ribas, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, Ioanis; Gninenko, S; Gomez, H; Hasinoff, M; Heinsius, F H; Hoffmann, D H H; Irastorza, I G; Jacoby, J; Jakovcic, K; Kang, D; Königsmann, K C; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Laki, B; Lasseur, C; Liolios, A; Ljubicic, cA; Lutz, G; Luzón, G; Miller, D; Morales, A; Morales, J; Nordt, A; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, G; Riege1, H; Rodríguez, A; Ruz, J; Savvidis, I; Semertzidis, Y K; Serpico, Pasquale Dario; Stewart, L; Villar, J; Vogel, J; Walckiers, L; Zioutas, K

    2007-01-01

    Axions are expected to be produced in the sun via the Primakoff process. They may be detected through the inverse process in the laboratory, under the influence of a strong magnetic field, giving rise to X-rays of energies in the range of a few keV. Such an Axion detector is the CERN Axion Solar Telescope (CAST), collecting data since 2003. Results have been published, pushing the axion-photon coupling g$_{a\\gamma}$ below the 10$^{-10}$ GeV$^{-1}$ limit at 95% CL, for axion masses less than 0.02 eV. This limit is nearly an order of magnitude lower than previous experimental limits and surpassed for the first time limits set from astrophysical arguments based on the energy-loss concept. The experiment is currently exploring axion masses in the range of 0.02 eV $< m_a <$ 1.1 eV. In the next run, currently under preparation, the axion mass explored will be extended up to the limit of 1.1 eV, testing for the first time the region of theoretical axion models with the axion helioscope method.

  13. Bose Einstein condensation of the classical axion field in cosmology?

    CERN Document Server

    Davidson, Sacha

    2013-01-01

    The axion is a motivated cold dark matter candidate, which it would be interesting to distinguish from weakly interacting massive particles. Sikivie has suggested that axions could behave differently during non-linear galaxy evolution, if they form a bose einstein condensate. Using classical equations of motion during linear structure formation, we explore whether "gravitational thermalisation" can drive axions to a bose einstein condensate. At linear order in G_N, we interpret that the principle activities of gravity are to expand the Universe and grow density fluctuations. From the anisotropic stress, we estimate a short dissipation scale for axions which does not confirm previous estimates of their gravitational thermalisation rate.

  14. Coupled Boltzmann computation of mixed axion neutralino dark matter in the SUSY DFSZ axion model

    CERN Document Server

    Bae, Kyu Jung; Lessa, Andre; Serce, Hasan

    2014-01-01

    The supersymmetrized DFSZ axion model is highly motivated not only because it offers solutions to both the gauge hierarchy and strong CP problems, but also because it provides a solution to the SUSY mu problem which naturally allows for a Little Hierarchy. We compute the expected mixed axion-neutralino dark matter abundance for the SUSY DFSZ axion model in two benchmark cases-- a natural SUSY model with a standard neutralino underabundance (SUA) and an mSUGRA/CMSSM model with a standard overabundance (SOA). Our computation implements coupled Boltzmann equations which track the radiation density along with neutralino, axion (produced thermally (TH) and via coherent oscillations (CO)), saxion (TH- and CO-produced), axino and gravitino densities. In the SUSY DFSZ model, axions, axinos and saxions go through the process of freeze-in-- in contrast to freeze-out or out-of-equilibrium production as in the SUSY KSVZ model-- resulting in thermal yields which are largely independent of the re-heat temperature. We find ...

  15. Racing Academy

    Science.gov (United States)

    Turner, Jim; Gavin, Carl; Owen, Martin

    2004-09-01

    This paper outlines an innovative education project that, by using a cutting-edge racing car physics simulation, will help create the next generation of engineers. The article gives an overview of this genre of games to give a background to the non-games expert. It also identifies key educational methodologies that have helped to form the goals of the project.

  16. Transcending race?

    DEFF Research Database (Denmark)

    Wilson, Fiona

    2007-01-01

    Using accounts of militant schoolteachers from a province in the central sierra of Peru, this article attempts to show how and why concepts of race and political commitment among teachers changed at three critical moments in Peruvian history: agrarian reform, mass unionisation, and Maoist insurge...

  17. Relativistic axions from collapsing Bose stars

    CERN Document Server

    Levkov, D G; Tkachev, I I

    2016-01-01

    The substructures of light bosonic (axion-like) dark matter may condense into compact Bose stars. We study collapses of the critical-mass stars caused by attractive self-interaction of the axion-like particles and find that these processes proceed in an unexpected universal way. First, nonlinear self-similar evolution (similar to "wave collapse" in plasma physics) forces the particles to fall into the star center. Second, collisions in the dense center create an outgoing stream of mildly relativistic particles which carries away an essential part of the star mass. The collapse stops when the star remnant is no longer able to support the self-similar infall feeding the collisions. We shortly discuss possible astrophysical and cosmological implications of these phenomena.

  18. Universal constraints on axions from inflation

    DEFF Research Database (Denmark)

    Ferreira, R. Z.; Sloth, M. S.

    2014-01-01

    We consider the presence of an axion like particle, sigma, with a generic CP violating axial coupling of the form (alpha sigma/f), where F (mu nu) is the gauge field strength of a generic abelian U(1) gauge group, not necessarily associated with the standard electromagnetism, and f is the decay...... that the generation of curvature perturbation at horizon crossing due to the axial coupling has a universal form and remains unmodified in terms of the xi parameter even if the axion, sigma, is not identified with the inflaton. As a consequence, it does not appear to be possible to generate CMB tensor perturbations...... through this mechanism, larger than the vacuum ones, without violating the observational constraints unless we combine this mechanism with a curvaton or if the sigma field becomes heavy and decays during inflation. Even in this last case there are non-trivial constraints coming from the slow...

  19. Mixed axion-wino dark matter

    Directory of Open Access Journals (Sweden)

    Kyu Jung Bae

    2015-07-01

    Full Text Available A variety of supersymmetric models give rise to a split mass spectrumcharacterized by very heavy scalars but sub-TeV gauginos, usually with awino-like LSP. Such models predict a thermally-produced underabundance ofwino-like WIMP dark matter so that non-thermal DM production mechanisms arenecessary.We examine the case where theories with a wino-like LSP are augmented by aPeccei-Quinn sector including an axion-axino-saxion supermultiplet in either theSUSY KSVZ or SUSY DFSZ models and with/without saxion decays to axions/axinos.We show allowed ranges of PQ breaking scale f_a for various cases which aregenerated by solving the necessary coupled Boltzmann equations.We also present results for a model with radiatively-driven naturalnessbut with a wino-like LSP.

  20. Large non-gaussianity in axion inflation.

    Science.gov (United States)

    Barnaby, Neil; Peloso, Marco

    2011-05-06

    The inflationary paradigm has enjoyed phenomenological success; however, a compelling particle physics realization is still lacking. Axions are among the best-motivated inflaton candidates, since the flatness of their potential is naturally protected by a shift symmetry. We reconsider the cosmological perturbations in axion inflation, consistently accounting for the coupling to gauge fields cΦFF, which is generically present in these models. This coupling leads to production of gauge quanta, which provide a new source of inflaton fluctuations, δΦ. For c≥10(2)M(p)(-1), these dominate over the vacuum fluctuations, and non-Gaussianity exceeds the current observational bound. This regime is typical for concrete realizations that admit a UV completion; hence, large non-Gaussianity is easily obtained in minimal and natural realizations of inflation.

  1. Black hole mergers and the QCD axion at Advanced LIGO

    Science.gov (United States)

    Arvanitaki, Asimina; Baryakhtar, Masha; Dimopoulos, Savas; Dubovsky, Sergei; Lasenby, Robert

    2017-02-01

    In the next few years, Advanced LIGO (aLIGO) may see gravitational waves (GWs) from thousands of black hole (BH) mergers. This marks the beginning of a new precision tool for physics. Here we show how to search for new physics beyond the standard model using this tool, in particular the QCD axion in the mass range μa˜10-14 to 10-10 eV . Axions (or any bosons) in this mass range cause rapidly rotating BHs to shed their spin into a large cloud of axions in atomic Bohr orbits around the BH, through the effect of superradiance (SR). This results in a gap in the mass vs spin distribution of BHs when the BH size is comparable to the axion's Compton wavelength. By measuring the spin and mass of the merging objects observed at LIGO, we could verify the presence and shape of the gap in the BH distribution produced by the axion. The axion cloud can also be discovered through the GWs it radiates via axion annihilations or level transitions. A blind monochromatic GW search may reveal up to 1 05 BHs radiating through axion annihilations, at distinct frequencies within ˜3 % of 2 μa . Axion transitions probe heavier axions and may be observable in future GW observatories. The merger events are perfect candidates for a targeted GW search. If the final BH has high spin, a SR cloud may grow and emit monochromatic GWs from axion annihilations. We may observe the SR evolution in real time.

  2. The racing dragon

    CERN Multimedia

    2009-01-01

    Dating back nearly 2000 years, the ancient Chinese tradition of Dragon Boat Racing was originally a celebration that fell on the 5th day of the 5th lunar month as a gesture to please the Gods and bring forth necessary rains to cultivate the lands. Now the CERN Canoe and Kayak Club, too, participates in this tradition, though not so much to please the Gods on the ritualistic date, but to bring forth giant smiles on the faces of members. Dragon Boat Racing has been rising steadily in popularity in Europe since the mid nineties and with the great potential to host and promote Dragon Boat Racing in the Geneva area, the CERN Canoe and Kayak Club, has taken the initiative to bring the sport to the region. Some members of the Club traveled to Dole in June to participate in the Festival Dragon Boat 2009. Under perfect sunny conditions, the team triumphed in their first ever tournament, cruising to a convincing first place overall finish. T...

  3. Hidden symmetries in dilaton-axion gravity

    CERN Document Server

    Kechkin, O V

    1996-01-01

    Four--dimensional Einstein--Maxwell--dilaton--axion system restricted to space--times with one non--null Killing symmetry is formulated as the three--dimensional gravity coupled sigma--model. Several alternative representations are discussed and the associated hidden symmetries are revealed. The action of target space isometries on the initial set of (non--dualized ) variables is found. New mulicenter solutions are obtained via generating technique based on the formulation in terms of the non--dualized variables.

  4. Multiverse dark matter: SUSY or axions

    Science.gov (United States)

    D'Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio

    2014-11-01

    The observed values of the cosmological constant and the abundance of Dark Matter (DM) can be successfully understood, using certain measures, by imposing the anthropic requirement that density perturbations go non-linear and virialize to form halos. This requires a probability distribution favoring low amounts of DM, i.e. low values of the PQ scale f for the QCD axion and low values of the superpartner mass scale for LSP thermal relics. In theories with independent scanning of multiple DM components, there is a high probability for DM to be dominated by a single component. For example, with independent scanning of f and , TeV-scale LSP DM and an axion solution to the strong CP problem are unlikely to coexist. With thermal LSP DM, the scheme allows an understanding of a Little SUSY Hierarchy with multi-TeV superpartners. Alternatively, with axion DM, PQ breaking before (after) inflation leads to f typically below (below) the projected range of the current ADMX experiment of f = (3 - 30) × 1011 GeV, providing strong motivation to develop experimental techniques for probing lower f.

  5. Multiverse Dark Matter: SUSY or Axions

    CERN Document Server

    D'Eramo, Francesco; Pappadopulo, Duccio

    2014-01-01

    The observed values of the cosmological constant {\\it and} the abundance of Dark Matter (DM) can be successfully understood, using certain measures, by imposing the anthropic requirement that density perturbations go non-linear and virialize to form halos. This requires a probability distribution favoring low amounts of DM, i.e. low values of the PQ scale $f$ for the QCD axion and low values of the superpartner mass scale $\\tilde{m}$ for LSP thermal relics. In theories with independent scanning of multiple DM components, there is a high probability for DM to be dominated by a single component. For example, with independent scanning of $f$ and $\\tilde{m}$, TeV-scale LSP DM and an axion solution to the strong CP problem are unlikely to coexist. With thermal LSP DM, the scheme allows an understanding of a Little SUSY Hierarchy with multi-TeV superpartners. Alternatively, with axion DM, PQ breaking before (after) inflation leads to $f$ typically below (below) the projected range of the current ADMX experiment of ...

  6. Axion monodromy and the weak gravity conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Hebecker, Arthur; Rompineve, Fabrizio [Heidelberg Univ. (Germany). Inst. for Theoretical Physics; Westphal, Alexander [DESY Hamburg (Germany). Theory Group

    2015-12-15

    Axions with broken discrete shift symmetry (axion monodromy) have recently played a central role both in the discussion of inflation and the 'relaxion' approach to the hierarchy problem. We suggest a very minimalist way to constrain such models by the weak gravity conjecture for domain walls: While the electric side of the conjecture is always satisfied if the cosine-oscillations of the axion potential are sufficiently small, the magnetic side imposes a cutoff, Λ{sup 3}∝mfM{sub pl}, independent of the height of these 'wiggles'. We compare our approach with the recent related proposal by Ibanez, Montero, Uranga and Valenzuela. We also discuss the non-trivial question which version, if any, of the weak gravity conjecture for domain walls should hold. In particular, we show that string compactifications with branes of different dimensions wrapped on different cycles lead to a 'geometric weak gravity conjecture' relating volumes of cycles, norms of corresponding forms and the volume of the compact space. Imposing this 'geometric conjecture', e.g. on the basis of the more widely accepted weak gravity conjecture for particles, provides at least some support for the (electric and magnetic) conjecture for domain walls.

  7. Black Hole Mergers and the QCD Axion at Advanced LIGO

    CERN Document Server

    Arvanitaki, Asimina; Dimopoulos, Savas; Dubovsky, Sergei; Lasenby, Robert

    2016-01-01

    In the next few years Advanced LIGO (aLIGO) may see gravitational waves (GWs) from thousands of black hole (BH) mergers. This marks the beginning of a new precision tool for physics. Here we show how to search for new physics beyond the standard model using this tool, in particular the QCD axion in the mass range ma ~ 10^-14 to 10^-10 eV. Axions (or any bosons) in this mass range cause rapidly rotating BHs to shed their spin into a large cloud of axions in atomic Bohr orbits around the BH, through the effect of superradiance. This results in a gap in the mass vs. spin distribution of BHs when the BH size is comparable to the axion's Compton wavelength. By measuring the spin and mass of the merging objects observed at LIGO, we could verify the presence and shape of the gap in the BH distribution produced by the axion. The axion cloud can also be discovered through the GWs it radiates via axion annihilations or level transitions. A blind monochromatic GW search may reveal up to 10^5 BHs radiating through axion ...

  8. Axion cold dark matter in view of BICEP2 results

    CERN Document Server

    Visinelli, L

    2014-01-01

    The properties of axions that constitute 100% of cold dark matter (CDM) depend on the tensor-to-scalar ratio $r$ at the end of inflation. If $r=0.20^{+0.07}_{-0.05}$ as reported by the BICEP2 collaboration, then ``half'' of the CDM axion parameter space is ruled out. Namely, the Peccei-Quinn symmetry must be broken after the end of inflation, and axions do not generate non-adiabatic primordial fluctuations. The cosmic axion density is then independent of the tensor-to-scalar ratio $r$, and the axion mass is expected to be in a narrow range that however depends on the cosmological model before primordial nucleosynthesis. In the standard $\\Lambda$CDM cosmology, the CDM axion mass range is $m_a = \\left(71 \\pm 2\\right) \\mu{\\rm eV} \\, (\\alpha^{\\rm dec}+1)^{6/7}$, where $\\alpha^{\\rm dec}$ is the fractional contributions to the cosmic axion density from decays of axionic strings and walls.

  9. Higgs inflation and suppression of axion isocurvature perturbation

    Energy Technology Data Exchange (ETDEWEB)

    Nakayama, Kazunori, E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Kavli Institute for the Physics and Mathematics of the Universe, UTIAS, University of Tokyo, Kashiwa 277-8583 (Japan); Takimoto, Masahiro [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)

    2015-09-02

    We point out that cosmological constraint from the axion isocurvature perturbation is relaxed if the Higgs field obtains a large field value during inflation in the DFSZ axion model. This scenario is consistent with the Higgs inflation model, in which two Higgs doublets have non-minimal couplings and play a role of inflaton.

  10. Photon-Axion conversions in transversely inhomogeneous magnetic fields

    OpenAIRE

    Redondo, Javier

    2010-01-01

    We compute the photon-axion conversion probability in an external magnetic field with a strong transverse gradient in the eikonal approximation for plane waves. We find it typically smaller than a comparable uniform case. Some insights into the phenomenon of photon-axion splitting are given.

  11. First axion results from the XENON100 experiment

    NARCIS (Netherlands)

    Aprile, E.; et al., [Unknown; Alfonsi, M.; Colijn, A.P.; Decowski, M.P.

    2014-01-01

    We present the first results of searches for axions and axionlike particles with the XENON100 experiment. The axion-electron coupling constant, gAe, has been probed by exploiting the axioelectric effect in liquid xenon. A profile likelihood analysis of 224.6 live days × 34-kg exposure has shown no e

  12. Higgs inflation and suppression of axion isocurvature perturbation

    Directory of Open Access Journals (Sweden)

    Kazunori Nakayama

    2015-09-01

    Full Text Available We point out that cosmological constraint from the axion isocurvature perturbation is relaxed if the Higgs field obtains a large field value during inflation in the DFSZ axion model. This scenario is consistent with the Higgs inflation model, in which two Higgs doublets have non-minimal couplings and play a role of inflaton.

  13. In the footsteps of axions or the like

    CERN Document Server

    CERN. Geneva

    2006-01-01

    Axions were invented to solve the strong CP-problem and are one of the leading dark matter particle candidates. Axions could be copiously produced in the Sun. In magnetic fields they can oscillate to photons and vice versa. The axion helioscope CAST uses an LHC magnet to convert solar axions to X-rays. Also, in the solar atmosphere the large scale magnetic fields reach occasionally several kGauss. Assuming the CAST working principle occurring there much more efficiently, it could explain the unexpected appearance of X-rays (from axions) or disappearance of light (into axions). Such processes can be behind persisting solar mysteries, suggesting the participation of a) solar magnetic fields, and b) radiatively decaying massive particles. Enigmatic behaviour leading to solar X-ray emission, coronal heating, flares, sunspots, etc. is considered as evidence of overlooked signature of axions or other particles with similar properties. New solar axion searches in the lab and with space X-ray telescopes, have been mo...

  14. Diluting the inflationary axion fluctuation by a stronger QCD in the early Universe

    CERN Document Server

    Choi, Kiwoon; Im, Sang Hui; Jeong, Kwang Sik

    2015-01-01

    We propose a new mechanism to suppress the axion isocurvature perturbation, while producing the right amount of axion dark matter, within the framework of supersymmetric axion models with the axion scale induced by supersymmetry breaking. The mechanism involves an intermediate phase transition to generate the Higgs \\mu-parameter, before which the weak scale is comparable to the axion scale and the resulting stronger QCD yields an axion mass heavier than the Hubble scale over a certain period. Combined with that the Hubble-induced axion scale during the primordial inflation is well above the intermediate axion scale at present, the stronger QCD in the early Universe suppresses the axion fluctuation to be small enough even when the inflationary Hubble scale saturates the current upper bound, while generating an axion misalignment angle of order unity.

  15. Diluting the inflationary axion fluctuation by a stronger QCD in the early Universe

    Directory of Open Access Journals (Sweden)

    Kiwoon Choi

    2015-11-01

    Full Text Available We propose a new mechanism to suppress the axion isocurvature perturbation, while producing the right amount of axion dark matter, within the framework of supersymmetric axion models with the axion scale induced by supersymmetry breaking. The mechanism involves an intermediate phase transition to generate the Higgs μ-parameter, before which the weak scale is comparable to the axion scale and the resulting stronger QCD yields an axion mass heavier than the Hubble scale over a certain period. Combined with that the Hubble-induced axion scale during the primordial inflation is well above the intermediate axion scale at present, the stronger QCD in the early Universe suppresses the axion fluctuation to be small enough even when the inflationary Hubble scale saturates the current upper bound, while generating an axion misalignment angle of order unity.

  16. Diluting the inflationary axion fluctuation by a stronger QCD in the early Universe

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Kiwoon, E-mail: kchoi@ibs.re.kr [Center for Theoretical Physics of the Universe, IBS, Daejeon 305-811 (Korea, Republic of); Chun, Eung Jin, E-mail: ejchun@kias.re.kr [Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of); Im, Sang Hui, E-mail: shim@ibs.re.kr [Center for Theoretical Physics of the Universe, IBS, Daejeon 305-811 (Korea, Republic of); Jeong, Kwang Sik, E-mail: ksjeong@pusan.ac.kr [Department of Physics, Pusan National University, Busan, 609-735 (Korea, Republic of)

    2015-11-12

    We propose a new mechanism to suppress the axion isocurvature perturbation, while producing the right amount of axion dark matter, within the framework of supersymmetric axion models with the axion scale induced by supersymmetry breaking. The mechanism involves an intermediate phase transition to generate the Higgs μ-parameter, before which the weak scale is comparable to the axion scale and the resulting stronger QCD yields an axion mass heavier than the Hubble scale over a certain period. Combined with that the Hubble-induced axion scale during the primordial inflation is well above the intermediate axion scale at present, the stronger QCD in the early Universe suppresses the axion fluctuation to be small enough even when the inflationary Hubble scale saturates the current upper bound, while generating an axion misalignment angle of order unity.

  17. Detecting ultralight axion dark matter wind with laser interferometers

    CERN Document Server

    Aoki, Arata

    2016-01-01

    The ultralight axion with mass around $10^{-23}$ eV is known as a candidate of dark matter. A peculiar feature of the ultralight axion is oscillating pressure in time, which produces oscillation of gravitational potentials. Since the solar system moves through the dark matter halo at the velocity of about $v \\sim 300 \\, \\text{km} / \\text{s} = 10^{-3}$, there exists axion wind, which looks like scalar gravitational waves for us. Hence, there is a chance to detect ultralight axion dark matter with a wide mass range by using laser interferometer detectors. We calculate the detector signal induced by the oscillating pressure of the ultralight axion field, which would be detected by future laser interferometer experiments. We also argue that the detector signal can be enhanced due to the resonance in modified gravity theory explaining the dark energy.

  18. Possible resonance effect of axionic dark matter in Josephson junctions.

    Science.gov (United States)

    Beck, Christian

    2013-12-06

    We provide theoretical arguments that dark-matter axions from the galactic halo that pass through Earth may generate a small observable signal in resonant S/N/S Josephson junctions. The corresponding interaction process is based on the uniqueness of the gauge-invariant axion Josephson phase angle modulo 2π and is predicted to produce a small Shapiro steplike feature without externally applied microwave radiation when the Josephson frequency resonates with the axion mass. A resonance signal of so far unknown origin observed by C. Hoffmann et al. [Phys. Rev. B 70, 180503(R) (2004)] is consistent with our theory and can be interpreted in terms of an axion mass m(a)c2=0.11  meV and a local galactic axionic dark-matter density of 0.05  GeV/cm3. We discuss future experimental checks to confirm the dark-matter nature of the observed signal.

  19. Axion Haloscopes with Toroidal Geometry at CAPP/IBS

    CERN Document Server

    Ko, B R

    2016-01-01

    The present state of the art axion haloscope employs a cylindrical resonant cavity in a solenoidal field. We, the Center for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science (IBS) in Korea, are also pursuing halo axion discovery using this cylindrical geometry. However, the presence of end caps of cavities increases challenges as we explore higher frequency regions for the axion at above 2 GHz. To overcome these challenges we exploit a toroidal design of cavity and magnetic field. A toroidal geometry offers several advantages, two of which are a larger volume for a given space and greatly reduced fringe fields which interfere with our preamps, in particular the planned quantum-based devices. We introduce the concept of toroidal axion haloscopes and present ongoing research activities and plans at CAPP/IBS.

  20. Non-Gaussianity from Axion Monodromy Inflation

    DEFF Research Database (Denmark)

    Hannestad, Steen; Haugboelle, Troels; R. Jarnhus, Philip;

    2010-01-01

    inflation in string theory, where the monodromy from wrapped branes extends the range of the closed string axions to beyond the Planck scale. The superimposed oscillations in the potential can lead to new signatures in the CMB spectrum and bispectrum. In particular the bispectrum will have a new distinct...... or larger while the power spectrum is almost featureless. This model is therefore an example of a string-inspired inflationary model which is testable mainly through its non-Gaussian features. Finally we provide a simple analytic fitting formula for the bispectrum which is accurate to approximately 5...

  1. A New Target for Cosmic Axion Searches

    CERN Document Server

    Baumann, Daniel; Wallisch, Benjamin

    2016-01-01

    Future CMB experiments have the potential to probe the density of relativistic species at the sub-percent level. Sensitivity at this level allows light thermal relics to be detected up to arbitrarily high decoupling temperatures. Conversely, the absence of a detection would require extra light species never to have been in equilibrium with the Standard Model. In this paper, we exploit this feature to demonstrate the sensitivity of future cosmological observations to the couplings of axions to all of the Standard Model degrees of freedom. In many cases, the constraints achievable from cosmology will surpass existing bounds from laboratory experiments and astrophysical observations by orders of magnitude.

  2. Axion mediated photon to dark photon mixing

    CERN Document Server

    Ejlli, Damian

    2016-01-01

    The interaction between dark/mirror sector and ordinary sector is considered, where the two sectors interact with each other by sharing the same QCD axion field. This feature makes possible the mixing between ordinary and dark/mirror photons in ordinary and dark electromagnetic fields. Exact and perturbative solutions of equation of motions describing the evolution of fields in ordinary and dark external magnetic fields are found. User friendly quantities such as transition probability rates, induced phase shifts and angle of rotation of the polarization plane of light are derived. Possible astrophysical and cosmological applications of this mechanism are suggested.

  3. New Target for Cosmic Axion Searches

    Science.gov (United States)

    Baumann, Daniel; Green, Daniel; Wallisch, Benjamin

    2016-10-01

    Future cosmic microwave background experiments have the potential to probe the density of relativistic species at the subpercent level. This sensitivity allows light thermal relics to be detected up to arbitrarily high decoupling temperatures. Conversely, the absence of a detection would require extra light species never to have been in equilibrium with the Standard Model. In this Letter, we exploit this feature to demonstrate the sensitivity of future cosmological observations to the couplings of axions to photons, gluons, and charged fermions. In many cases, the constraints achievable from cosmology will surpass existing bounds from laboratory experiments and astrophysical observations by orders of magnitude.

  4. Electric and magnetic energy at axion haloscopes

    CERN Document Server

    Ko, B R; Jang, W; Choi, J; Kim, D; Lee, M J; Lee, J; Won, E; Semertzidis, Y K

    2016-01-01

    We review a recent letter published in Phys. Rev. Lett. $\\textbf{116}$, 161804 (2016) of which the main argument is that the mode dependent magnetic form factors at axion haloscopes depend on the position of the cavity inside the solenoid while the corresponding electric form factors do not. We, however, find no such dependence, which is also equivalent to the statement that the electric and corresponding magnetic energy stored in the cavity modes are the same regardless of the position of the cavity inside the solenoid. Furthermore, we extend the statement to the cases satisfying $\\vec{\

  5. CAST constraints on the axion-electron coupling

    Energy Technology Data Exchange (ETDEWEB)

    Barth, K.; Davenport, M.; Lella, L. Di [European Organization for Nuclear Research (CERN), Geneve (Switzerland); Belov, A. [Institute for Nuclear Research (INR), Russian Academy of Sciences, Moscow (Russian Federation); Beltran, B.; Carmona, J.M.; Dafni, T.; Galan, J.; García, J.A. [Laboratorio de Fisica Nuclear y Altas Energias, Universidad de Zaragoza, Zaragoza (Spain); Braeuninger, H.; Englhauser, J.; Friedrich, P. [Max-Planck-Institut fuer extraterrestrische Physik, Garching (Germany); Collar, J.I. [Enrico Fermi Institute and KICP, University of Chicago, Chicago, IL (United States); Eleftheriadis, C. [Aristoteles University of Thessaloniki, Thessaloniki (Greece); Fanourakis, G.; Geralis, T. [National Center for Scientific Research ' ' Demokritos' ' , Athens (Greece); Ferrer-Ribas, E.; Giomataris, I. [IRFU, Centre d' Etudes Nucleaires de Saclay (CEA-Saclay), Gif-sur-Yvette (France); Fischer, H.; Franz, J., E-mail: Jaime.Ruz@cern.ch, E-mail: Julia.Vogel@cern.ch, E-mail: redondo@mpp.mpg.de [Albert-Ludwigs-Universitaet Freiburg, Freiburg (Germany); and others

    2013-05-01

    In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axio-recombination, the ''BCA processes.'' Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling g{sub ae} and axion-photon interaction strength g{sub aγ} using the CAST phase-I data (vacuum phase). For m{sub a}∼<10 meV/c{sup 2} we find g{sub aγ} g{sub ae} < 8.1 × 10{sup −23} GeV{sup −1} at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission.

  6. Axion searches with the EDELWEISS-II experiment

    CERN Document Server

    Armengaud, E; Augier, C; Benoit, A; Bergé, L; Bergmann, T; Blümer, J; Broniatowski, A; Brudanin, V; Camus, P; Cazes, A; Censier, B; Chapellier, M; Charlieux, F; Couëdo, F; Coulter, P; Cox, G A; de Boissière, T; De Jesus, M; Dolgorouky, Y; Drillien, A A; Dumoulin, L; Eitel, K; Filosofov, D; Fourches, N; Gascon, J; Gerbier, G; Gros, M; Hehn, L; Henry, S; Hervé, S; Heuermann, G; Holtzer, N; Humbert, V; Juillard, A; Kéfélian, C; Kleifges, M; Kluck, H; Kozlov, V; Kraus, H; Kudryavtsev, V A; Sueur, H Le; Mancuso, M; Marrache-Kikuchi, C; Marnieros, S; Menshikov, A; Navick, X-F; Nones, C; Olivieri, E; Pari, P; Paul, B; Piro, M C; Rigaut, O; Robinson, M; Rozov, S; Sanglard, V; Schmidt, B; Siebenborn, B; Tcherniakhovski, D; Tenconi, M; Vagneron, L; Walker, R J; Weber, M; Yakushev, E; Zhang, X

    2013-01-01

    We present new constraints on the couplings of axions and more generic axion-like particles using data from the EDELWEISS-II experiment. The EDELWEISS experiment, located at the Underground Laboratory of Modane, primarily aims at the direct detection of WIMPs using germanium bolometers. It is also sensitive to the low-energy electron recoils that would be induced by solar or dark matter axions. Using a total exposure of up to 448 kg.d, we searched for axion-induced electron recoils down to 2.5 keV within four scenarios involving different hypotheses on the origin and couplings of axions. We set a 95% CL limit on the coupling to photons $g_{A\\gamma}<2.13\\times 10^{-9}$ GeV$^{-1}$ in a mass range not fully covered by axion helioscopes. We also constrain the coupling to electrons, $g_{Ae} < 2.56\\times 10^{-11}$, similar to the more indirect solar neutrino bound. Finally we place a limit on $g_{Ae}\\times g_{AN}^{\\rm eff}<4.70 \\times 10^{-17}$, where $g_{AN}^{\\rm eff}$ is the effective axion-nucleon coupl...

  7. Search for Solar Axions with the CAST-Experiment

    CERN Document Server

    Vogel, J.; Aune, S.; Autiero, D.; Barth, K.; Belov, A.; Beltran, B.; Borghi, S.; Bourlis, G.; Boydag, F. S.; Brauninger, H.; Carmona, J.; Cebrian, S.; Cetin, S. A.; Collar, J.I.; Dafni, T.; Davenport, M.; Di Lella, L.; Dogan, O. B.; Elefheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Fisher, H.; Franz, J.; Galan, J.; Geralis, T.; Giomataris, I.; Gninenko, S.; Gomez, H.; Hasinoff, M.; Heinsius, H.; Hikmet, I.; Hoffmann, D. H. H.; Irastorza, I. G.; Jacoby, J.; Jakovcic, K.; Kang, D.; Konigsmann, K.; Kotthaus, R.; Krcmar, M.; Kousouris, K.; Kuster, M.; Lakic, B.; Lasseur, C.; Liolios, A.; Ljubicic, A.; Lutz, G.; Luzon, G.; Miller, D.; Morales, J.; Niinikoski, T.; Nordt, A.; Ortiz, A.; Papaevangelou, T.; Pivovaroff, M.; Placci, A.; Raffelt, G.; Riege, H.; Rodriguez, A.; Ruz, J.; Savvidis, I.; Semertzidis, Y.; Serpico, P.; Soufli, R.; Stewart, L.; Tzamarias, S.; Van Bibber, K.; Villar, J.; Walckiers, L.; Zioutas, K.; Morales, A.

    2008-01-01

    Solar axions can be produced in the Sun via the so-called Primakoff effect. The CERN Axion Solar Telescope (CAST) uses an LHC prototype magnet of about 9 T to reconvert these axions into photons. The magnet is able to follow the Sun for about 3 hours per day. Three different X-Ray detectors are mounted on its ends to detect photons from axion-to-photon conversion: a Time Projection Chamber (TPC), a MICROMEGAS (MICROMEsh GAseous Structure) and a Charge Coupled Device (CCD). For the CCD an X-ray focusing device is used to improve the signal-to-background ratio significantly. With the completion of CAST'S first phase, the current limits on the coupling constant gaγ for axion masses up to 0.02 eV have been improved. In its second phase, CAST extends the axion mass range by filling the magnet with a buffer gas. Masses up to about 0.4 eV have already been covered and thus the experiment is entering the regions favored by axion models. This paper will present the status of CAST'S second phase.

  8. Modulation sensitive search for nonvirialized dark-matter axions

    Science.gov (United States)

    Hoskins, J.; Crisosto, N.; Gleason, J.; Sikivie, P.; Stern, I.; Sullivan, N. S.; Tanner, D. B.; Boutan, C.; Hotz, M.; Khatiwada, R.; Lyapustin, D.; Malagon, A.; Ottens, R.; Rosenberg, L. J.; Rybka, G.; Sloan, J.; Wagner, A.; Will, D.; Carosi, G.; Carter, D.; Duffy, L. D.; Bradley, R.; Clarke, J.; O'Kelley, S.; van Bibber, K.; Daw, E. J.

    2016-10-01

    Nonvirialized dark-matter axions may be present in the Milky Way halo in the form of low-velocity-dispersion flows. The Axion Dark-Matter eXperiment performed a search for the conversion of these axions into microwave photons using a resonant cavity immersed in a strong, static magnetic field. The spread of photon energy in these measurements was measured at spectral resolutions of the order of 1 Hz and below. If the energy variation were this small, the frequency modulation of any real axion signal due to the orbital and rotational motion of Earth would become non-negligible. Conservative estimates of the expected signal modulation were made and used as a guide for the search procedure. The photon frequencies covered by this search are 812-852 and 858-892 MHz, which correspond to an axion mass of 3.36-3.52 and 3.55 - 3.69 μ eV . No axion signal was found, and limits were placed on the maximum local density of nonvirialized axions of these masses.

  9. Axion searches with the EDELWEISS-II experiment

    Energy Technology Data Exchange (ETDEWEB)

    Armengaud, E.; Boissière, T. de [CEA, Centre d' Etudes Saclay, IRFU, 91191 Gif-Sur-Yvette Cedex (France); Arnaud, Q.; Augier, C.; Benoit, A.; Cazes, A.; Censier, B.; Charlieux, F.; Jesus, M. De [IPNL, Université de Lyon, Université Lyon 1, CNRS/IN2P3, 4 rue E. Fermi 69622 Villeurbanne cedex (France); Benoit, A.; Camus, P. [CNRS-Néel, 25 Avenue des Martyrs, 38042 Grenoble cedex 9 (France); Bergé, L.; Broniatowski, A.; Chapellier, M.; Couëdo, F. [CSNSM, Université Paris-Sud, IN2P3-CNRS, bat 108, 91405 Orsay (France); Bergmann, T. [Karlsruhe Institute of Technology, Institut für Prozessdatenverarbeitung und Elektronik, 76021 Karlsruhe (Germany); Blümer, J.; Cox, G.A. [Karlsruhe Institute of Technology, Institut für Experimentelle Kernphysik, 76128 Karlsruhe (Germany); Brudanin, V. [Laboratory of Nuclear Problems, JINR, Joliot-Curie 6, 141980 Dubna, Moscow region (Russian Federation); Coulter, P., E-mail: claudia.nones@cea.fr, E-mail: thibault.main-de-boissiere@cea.fr, E-mail: eric.armengaud@cea.fr [University of Oxford, Department of Physics, Keble Road, Oxford OX1 3RH (United Kingdom); and others

    2013-11-01

    We present new constraints on the couplings of axions and more generic axion-like particles using data from the EDELWEISS-II experiment. The EDELWEISS experiment, located at the Underground Laboratory of Modane, primarily aims at the direct detection of WIMPs using germanium bolometers. It is also sensitive to the low-energy electron recoils that would be induced by solar or dark matter axions. Using a total exposure of up to 448 kg.d, we searched for axion-induced electron recoils down to 2.5 keV within four scenarios involving different hypotheses on the origin and couplings of axions. We set a 95 % CL limit on the coupling to photons g{sub Aγ} < 2.15 × 10{sup −9} GeV{sup −1} in a mass range not fully covered by axion helioscopes. We also constrain the coupling to electrons, g{sub Ae} < 2.59 × 10{sup −11}, similar to the more indirect solar neutrino bound. Finally we place a limit on g{sub Ae} × g{sub AN}{sup eff} < 4.82 × 10{sup −17}, where g{sub AN}{sup eff} is the effective axion-nucleon coupling for {sup 57}Fe. Combining these results we fully exclude the mass range 0.92 eV < m{sub A} < 80 keV for DFSZ axions and 5.78 eV < m{sub A} < 40 keV for KSVZ axions.

  10. The cern axion solar telescope (CAST): an update

    Science.gov (United States)

    Andriamonje, S.; Arsov, V.; Aune, S.; Aune, T.; Avignone, F. T.; Barth, K.; Belov, A.; Beltran, B.; Bräuninger, H.; Carmona, J.; Cebrián, S.; Chesi, E.; Cipolla, G.; Collar, J.; Creswick, R.; Dafni, T.; Davenport, M.; Dedousis, S.; Delattre, M.; Delbart, A.; Deoliveira, R.; Dilella, L.; Eleftheriadis, C.; Engelhauser, J.; Fanourakis, G.; Farach, H.; Ferrer, E.; Fischer, H.; Formenti, F.; Franz, J.; Friedrich, P.; Geralis, T.; Giomataris, I.; Gninenko, S.; Golubev, N.; Hartmann, R.; Hasinoff, M.; Heinsius, F.-H.; Hoffmann, D. H. H.; Irastorza, I.; Jacoby, J.; Joux, J.-N.; Kang, D.; Königsmann, K.; Kotthaus, R.; Krcmar, M.; Kuster, M.; Lakic, B.; Lasseur, C.; Liolios, A.; Lippitsch, A.; Ljubicic, A.; Lutz, G.; Luzon, G.; Morales, A.; Morales, J.; Mutterer, M.; Nikolaidis, A.; de Solorzano, A. Ortiz; Papaevangelou, T.; Placci, A.; Raffelt, G.; Rammos, P.; Robert, J. P.; Ruz, J.; Sarsa, M.; Schill, C.; Serber, W.; Semertzidis, Y.; Vieira, J.; Villar, J.; Vullierme, B.; Walckiers, L.; Zioutas, K.

    2005-01-01

    The CERN Axion Solar Telescope (CAST), a 10 meter long LHC, 9 Tesla, test magnet is mounted on a moving platform that tracks the sun about 1.5 hours during sunrise, again during sunset. It moves ±80 vertically and ±400 horizontally. It has been taking data continuously since July 10, 2003. Data analyzed thus far yield an upper bound on the photon-axion coupling constant, gaγγ ⩽ 3 × 10-10 GeV-1 for axion masses less than 5 × 10-2 eV.

  11. Accelerating dark-matter axion searches with quantum measurement technology

    CERN Document Server

    Zheng, Huaixiu; Brierley, R T; Girvin, S M; Lehnert, K W

    2016-01-01

    The axion particle, a consequence of an elegant hypothesis that resolves the strong-CP problem of quantum chromodynamics, is a plausible origin for cosmological dark matter. In searches for axionic dark matter that detect the conversion of axions to microwave photons, the quantum noise associated with microwave vacuum fluctuations will soon limit the rate at which parameter space is searched. Here we show that this noise can be partially overcome either by squeezing the quantum vacuum using recently developed Josephson parametric devices, or by using superconducting qubits to count microwave photons.

  12. The Rethermalizing Bose-Einstein Condensate of Dark Matter Axions

    CERN Document Server

    Banik, Nilanjan; Sikivie, Pierre; Todarello, Elisa Maria

    2015-01-01

    The axions produced during the QCD phase transition by vacuum realignment, string decay and domain wall decay thermalize as a result of their gravitational self-interactions when the photon temperature is approximately 500 eV. They then form a Bose-Einstein condensate (BEC). Because the axion BEC rethermalizes on time scales shorter than the age of the universe, it has properties that distinguish it from other forms of cold dark matter. The observational evidence for caustic rings of dark matter in galactic halos is explained if the dark matter is axions, at least in part, but not if the dark matter is entirely WIMPs or sterile neutrinos.

  13. Dilution of axion dark radiation by thermal inflation

    CERN Document Server

    Hattori, Hironori; Omoto, Naoya; Seto, Osamu

    2015-01-01

    Axion in the Peccei-Quinn (PQ) mechanism provides a promising solution to the strong CP problem in the standard model of particle physics. Coherently generated PQ scalar fields could dominate the energy density in the early Universe and decay into relativistic axions, which would confront with the current dark radiation constraints. We study the possibility that a thermal inflation driven by a $U(1)$ gauged Higgs field dilutes such axions. A well motivated extra gauged $U(1)$ would be the local $B-L$ symmetry. We also discuss the implication for the case of $U(1)_{B-L}$ and available baryogenesis mechanism in such cosmology.

  14. Dilution of axion dark radiation by thermal inflation

    Science.gov (United States)

    Hattori, Hironori; Kobayashi, Tatsuo; Omoto, Naoya; Seto, Osamu

    2015-07-01

    Axions in the Peccei-Quinn (PQ) mechanism provide a promising solution to the strong C P problem in the standard model of particle physics. Coherently generated PQ scalar fields could dominate the energy density in the early Universe and decay into relativistic axions, which would conflict with the current dark radiation constraints. We study the possibility that a thermal inflation driven by a U (1 ) gauged Higgs field dilutes such axions. A well-motivated extra gauged U (1 ) would be the local B -L symmetry. We also discuss the implication for the case of U (1 )B-L and an available baryogenesis mechanism in such cosmology.

  15. Testing axion physics in a Josephson junction environment

    CERN Document Server

    Beck, Christian

    2011-01-01

    We suggest that experiments based on Josephson junctions, SQUIDS, and coupled Josephson qubits can be used to construct a resonant environment for dark matter axions. We propose experimental setups in which axionic interaction strengths in a Josephson junction environment can be tested, similar in nature to recent experiments that test for quantum entanglement of two coupled Josephson qubits. We point out that the parameter values relevant for early-universe axion cosmology are accessible with present day's achievements in nanotechnology. We work out how typical dark matter and dark energy signals would look like in a novel detector that exploits this effect.

  16. Energy Dissipation of Axionic Boson Stars in Magnetized Conducting Media

    CERN Document Server

    Iwazaki, A

    1999-01-01

    Axions are possible candidates of dark matter in the present Universe. They have been argued to form axionic boson stars. Since they are shown to possess oscillating electric fields in a magnetic field, they loose their energies in magnetized conducting media. We show that colliding with a white dwarf, the axionic boson stars dissipate their energies with the rate being roughly $\\sim 10^{35}$ erg/s. According to recent evaluation of the population of the white dwarfs as candidates of MACHOs, we estimate that the event rate of the collisions is roughly 4 per year in a solid angle $5^{\\circ}\\times 5^{\\circ}$.

  17. Suppressing the QCD axion abundance by hidden monopoles

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Masahiro [Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Takahashi, Fuminobu [Tokyo Univ., Miyagi (Japan). Dept. of Physics; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Yamada, Masaki [Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; DESY Hamburg (Germany)

    2015-11-15

    We study the Witten effect of hidden monopoles on the QCD axion dynamics, and show that its abundance as well as isocurvature perturbations can be significantly suppressed if there is a sufficient amount of hidden monopoles. When the hidden monopoles make up a significant fraction of dark matter, the Witten effect suppresses the abundance of axion with the decay constant smaller than 10{sup 12} GeV. The cosmological domain wall problem of the QCD axion can also be avoided, relaxing the upper bound on the decay constant when the Peccei-Quinn symmetry is spontaneously broken after inflation.

  18. Suppressing the QCD axion abundance by hidden monopoles

    Directory of Open Access Journals (Sweden)

    Masahiro Kawasaki

    2016-02-01

    Full Text Available We study the Witten effect of hidden monopoles on the QCD axion dynamics, and show that its abundance as well as isocurvature perturbations can be significantly suppressed if there is a sufficient amount of hidden monopoles. When the hidden monopoles make up a significant fraction of dark matter, the Witten effect suppresses the abundance of axion with the decay constant smaller than 1012GeV. The cosmological domain wall problem of the QCD axion can also be avoided, relaxing the upper bound on the decay constant when the Peccei–Quinn symmetry is spontaneously broken after inflation.

  19. Cosmological bounds on sub-MeV mass axions

    DEFF Research Database (Denmark)

    Cadamuro, Davide; Hannestad, Steen; Raffelt, Georg;

    2011-01-01

    Axions with mass ma >~ 0.7 eV are excluded by cosmological precision data because they provide too much hot dark matter. While for ma >~ 20 eV the a → 2γ lifetime drops below the age of the universe, we show that the cosmological exclusion range can be extended to 0.7eV lesssim ma lesssim 300 ke......V, primarily by the cosmic deuterium abundance: axion decays would strongly modify the baryon-to-photon ratio at BBN relative to the one at CMB decoupling. Additional arguments include neutrino dilution relative to photons by axion decays and spectral CMB distortions. Our new cosmological constraints...

  20. Search for sub-eV mass solar axions by the CERN Axion Solar Telescope with 3He buffer gas.

    Science.gov (United States)

    Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Ezer, C; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Gazis, E N; Geralis, T; Giomataris, I; Gninenko, S; Gómez, H; Gruber, E; Guthörl, T; Hartmann, R; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovčić, K; Karuza, M; Königsmann, K; Kotthaus, R; Krčmar, M; Kuster, M; Lakić, B; Laurent, J M; Liolios, A; Ljubičić, A; Lozza, V; Lutz, G; Luzón, G; Morales, J; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Rashba, T; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J A; Vogel, J K; Yildiz, S C; Zioutas, K

    2011-12-23

    The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using (3)He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with (4)He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV≲m(a)≲0.64 eV. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g(aγ)≲2.3×10(-10) GeV(-1) at 95% C.L., the exact value depending on the pressure setting. Kim-Shifman-Vainshtein-Zakharov axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In the future we will extend our search to m(a)≲1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

  1. Non-Gaussianity from Axion Monodromy Inflation

    CERN Document Server

    Hannestad, Steen; Jarnhus, Philip R; Sloth, Martin S

    2010-01-01

    We study the primordial non-Gaussinity predicted from simple models of inflation with a linear potential and superimposed oscillations. This generic form of the potential is predicted by the axion monodromy inflation model, that has recently been proposed as a possible realization of chaotic inflation in string theory, where the monodromy from wrapped branes extends the range of the closed string axions to beyond the Planck scale. The superimposed oscillations in the potential can lead to new signatures in the CMB spectrum and bispectrum. In particular the bispectrum will have a new distinct shape. We calculate the power spectrum and bispectrum of curvature perturbations in the model, as well as make analytic estimates in various limiting cases. From the numerical analysis we find that for a wide range of allowed parameters the model produces a feature in the bispectrum with fnl ~ 50 or larger while the power spectrum is almost featureless. This model is therefore an example of a string-inspired inflationary ...

  2. Non-gaussianity from axion monodromy inflation

    Energy Technology Data Exchange (ETDEWEB)

    Hannestad, Steen; Haugbolle, Troels; Jarnhus, Philip R. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Sloth, Martin S., E-mail: sth@phys.au.dk, E-mail: haugboel@nbi.ku.dk, E-mail: pjarn@phys.au.dk, E-mail: martin.sloth@cern.ch [CERN, Physics Department, Theory Unit, CH-1211 Geneva 23 (Switzerland)

    2010-06-01

    We study the primordial non-Gaussianity predicted from simple models of inflation with a linear potential and superimposed oscillations. This generic form of the potential is predicted by the axion monodromy inflation model, that has recently been proposed as a possible realisation of chaotic inflation in string theory, where the monodromy from wrapped branes extends the range of the closed string axions to beyond the Planck scale. The superimposed oscillations in the potential can lead to new signatures in the CMB spectrum and bispectrum. In particular the bispectrum will have a new distinct shape. We calculate the power spectrum and bispectrum of curvature perturbations in the model, as well as make analytic estimates in various limiting cases. From the numerical analysis we find that for a wide range of allowed parameters the model produces a feature in the bispectrum with f{sub NL} ∼ 5−50 or larger while the power spectrum is almost featureless. This model is therefore an example of a string inspired inflationary model which is testable mainly through its non-Gaussian features. Finally we provide a simple analytic fitting formula for the bispectrum which is accurate to approximately 5 % in all cases, and easily implementable in codes designed to provide non-Gaussian templates for CMB analyses.

  3. Cosmic axion background propagation in galaxies

    CERN Document Server

    Day, Francesca V

    2015-01-01

    Many extensions of the Standard Model include axions or axion-like particles (ALPs). Here we study ALP to photon conversion in the magnetic field of the Milky Way and starburst galaxies. By modelling the effects of the coherent and random magnetic fields, the warm ionized medium and the warm neutral medium on the conversion process, we simulate maps of the conversion probability across the sky for a range of ALP energies. In particular, we consider a diffuse cosmic ALP background (CAB) analogous to the CMB, whose existence is suggested by string models of inflation. ALP-photon conversion of a CAB in the magnetic fields of galaxy clusters has been proposed as an explanation of the cluster soft X-ray excess. We therefore study the phenomenology and expected photon signal of CAB propagation in the Milky Way. We find that, for the CAB parameters required to explain the cluster soft X-ray excess, the photon flux from ALP-photon conversion in the Milky Way would be unobservably small. The ALP-photon conversion prob...

  4. Cosmic axion background propagation in galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Day, Francesca V., E-mail: francesca.day@physics.ox.ac.uk

    2016-02-10

    Many extensions of the Standard Model include axions or axion-like particles (ALPs). Here we study ALP to photon conversion in the magnetic field of the Milky Way and starburst galaxies. By modelling the effects of the coherent and random magnetic fields, the warm ionized medium and the warm neutral medium on the conversion process, we simulate maps of the conversion probability across the sky for a range of ALP energies. In particular, we consider a diffuse cosmic ALP background (CAB) analogous to the CMB, whose existence is suggested by string models of inflation. ALP–photon conversion of a CAB in the magnetic fields of galaxy clusters has been proposed as an explanation of the cluster soft X-ray excess. We therefore study the phenomenology and expected photon signal of CAB propagation in the Milky Way. We find that, for the CAB parameters required to explain the cluster soft X-ray excess, the photon flux from ALP–photon conversion in the Milky Way would be unobservably small. The ALP–photon conversion probability in galaxy clusters is 3 orders of magnitude higher than that in the Milky Way. Furthermore, the morphology of the unresolved cosmic X-ray background is incompatible with a significant component from ALP–photon conversion. We also consider ALP–photon conversion in starburst galaxies, which host much higher magnetic fields. By considering the clumpy structure of the galactic plasma, we find that conversion probabilities comparable to those in clusters may be possible in starburst galaxies.

  5. Searching for Axion Dark Matter in Atoms: Oscillating Electric Dipole Moments and Spin-Precession Effects

    CERN Document Server

    Roberts, Benjamin M; Flambaum, Victor V; Dzuba, Vladimir A

    2015-01-01

    We propose to search for axion dark matter via the oscillating electric dipole moments that axions induce in atoms and molecules. These moments are produced through the intrinsic oscillating electric dipole moments of nucleons and through the $P,T$-violating nucleon-nucleon interaction mediated by pion exchange, both of which arise due to the axion-gluon coupling, and also directly through the axion-electron interaction. Axion dark matter may also be sought for through the spin-precession effects that axions produce by directly coupling to fermion spins.

  6. Axion cosmology with long-lived domain walls

    CERN Document Server

    Hiramatsu, Takashi; Saikawa, Ken'ichi; Sekiguchi, Toyokazu

    2012-01-01

    We investigate the cosmological constraints on axion models where the domain wall number is greater than one. In these models, multiple domain walls attached to strings are formed, and they survive for a long time. Their annihilation occurs due to the effects of explicit symmetry breaking term which might be raised by Planck-scale physics. We perform three-dimensional lattice simulations and compute the spectra of axions and gravitational waves produced by long-lived domain walls. Using the numerical results, we estimated relic density of axions and gravitational waves. We find that the existence of long-lived domain walls leads to the overproduction of cold dark matter axions, while the density of gravitational waves is too small to observe at the present time. Combining the results with other observational constraints, we find that the whole parameter region of models are excluded unless an unacceptable fine-tuning exists.

  7. Non-thermal Axion Dark Radiation and Constraints

    CERN Document Server

    Mazumdar, Anupam; Saikawa, Ken'ichi

    2016-01-01

    The Peccei-Quinn mechanism presents a neat solution to the strong CP problem. As a by-product, it provides an ideal dark matter candidate, "the axion", albeit with a tiny mass. Axions therefore can act as dark radiation if excited with large momenta after the end of inflation. Nevertheless, the recent measurement of relativistic degrees of freedom from cosmic microwave background radiation strictly constrains the abundance of such extra relativistic species. We show that ultra-relativistic axions can be abundantly produced if the Peccei-Quinn field was initially displaced from the minimum of the potential. This in lieu places an interesting constraint on the axion dark matter window with large decay constant which is expected to be probed by future experiments. Moreover, an upper bound on the reheating temperature can be placed, which further constrains the thermal history of our Universe.

  8. Dielectric Haloscopes: A New Way to Detect Axion Dark Matter

    CERN Document Server

    Caldwell, Allen; Majorovits, Bela; Millar, Alexander; Raffelt, Georg; Redondo, Javier; Reimann, Olaf; Simon, Frank; Steffen, Frank

    2016-01-01

    We propose a new strategy to search for dark matter axions in the mass range of 40--400 $\\mu$eV by introducing dielectric haloscopes, which consist of dielectric disks placed in a magnetic field. The changing dielectric media cause discontinuities in the axion-induced electric field, leading to the generation of propagating electromagnetic waves to satisfy the continuity requirements at the interfaces. Large-area disks with adjustable distances boost the microwave signal (10--100 GHz) to an observable level and allow one to scan over a broad axion mass range. A sensitivity to QCD axion models is conceivable with 80 disks of 1 m$^2$ area contained in a $10$ Tesla field.

  9. Multiple-cavity detector for axion dark matter search

    Science.gov (United States)

    Jeong, Junu; Ahn, Saebyeok; Youn, Sungwoo; Semertzidis, Yannis

    2017-01-01

    Exploring higher frequency regions in axion dark matter searches using microwave cavity detectors requires a smaller size of the cavity as the TM010 frequency scales inversely with the cavity radius. One of the intuitive ways to make a maximal use of a given magnet volume, and thereby to increase the experimental sensitivity, is to bundle multiple cavities together and combine their individual outputs ensuring phase-matching of the coherent axion signal. The Experiment of Axion Search aT CAPP (EAST-C) is a dedicated project to develop multiple-cavity systems at the Centre for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science (IBS). In this poster, the conceptual design of the phase-matching mechanism and experimental feasibility using a quadruple-cavity system will be presented.

  10. Dielectric Haloscopes: A New Way to Detect Axion Dark Matter.

    Science.gov (United States)

    Caldwell, Allen; Dvali, Gia; Majorovits, Béla; Millar, Alexander; Raffelt, Georg; Redondo, Javier; Reimann, Olaf; Simon, Frank; Steffen, Frank

    2017-03-03

    We propose a new strategy to search for dark matter axions in the mass range of 40-400 μeV by introducing dielectric haloscopes, which consist of dielectric disks placed in a magnetic field. The changing dielectric media cause discontinuities in the axion-induced electric field, leading to the generation of propagating electromagnetic waves to satisfy the continuity requirements at the interfaces. Large-area disks with adjustable distances boost the microwave signal (10-100 GHz) to an observable level and allow one to scan over a broad axion mass range. A sensitivity to QCD axion models is conceivable with 80 disks of 1  m^{2} area contained in a 10 T field.

  11. First results from the CERN Axion Solar Telescope (CAST)

    CERN Document Server

    Andriamonje, Samuel A; Aune, S; Autiero, D; Barth, K; Belov, A; Beltran, B; Bräuninger, H; Carmona, J M; Cebrián, S; Chesi, Enrico Guido; Collar, J I; Creswick, R; Dafni, T; Davenport, M; Di Lella, L; Englhauser, J; Fanourakis, G K; Farach, H A; Ferrer, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, Ioanis; Gninenko, S; Goloubev, N; Hasinoff, M D; Heinsius, F H; Hoffmann, Dieter H H; Irastorza, I G; Jacoby, J; Kang, D; Königsmann, K C; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Lakic, B; Lasseur, C; Liolios, A; Ljubicic, A; Lutz, Gerhard; Luzón, G; Miller, D W; Morales, A; Mutterer, M; Nikolaidis, A; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, Georg G; Ruz, J; Riege, H; Sarsa, M L; Savvidis, I; Serber, W; Serpico, Pasquale Dario; Semertzidis, Y K; Vieira, J D; Villar, José Angel; Walckiers, L; Zachariadou, K; Zioutas, Konstantin

    2005-01-01

    Hypothetical axion-like particles with a two-photon interaction would be produced in the Sun by the Primakoff process. In a laboratory magnetic field (``axion helioscope'') they would be transformed into X-rays with energies of a few keV. Using a decommissioned LHC test magnet, CAST has been running for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling < 1.16 10^{-10} GeV^-1 at 95% CL for m_a <~0.02 eV. This limit is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment in this axion mass range.

  12. A scientist finally proves existence of elusive axion

    CERN Multimedia

    2006-01-01

    "Using a visual target/detector, a University of Buffalo researcher has revealed the existence of the axion, a tiny particle with no charge, a very low mass and a lifetime much shorter than a nanosecond." (1,5 page)

  13. Dielectric haloscopes to search for axion dark matter: theoretical foundations

    Science.gov (United States)

    Millar, Alexander J.; Raffelt, Georg G.; Redondo, Javier; Steffen, Frank D.

    2017-01-01

    We study the underlying theory of dielectric haloscopes, a new way to detect dark matter axions. When an interface between different dielectric media is inside a magnetic field, the oscillating axion field acts as a source of electromagnetic waves, which emerge in both directions perpendicular to the surface. The emission rate can be boosted by multiple layers judiciously placed to achieve constructive interference and by a large transverse area. Starting from the axion-modified Maxwell equations, we calculate the efficiency of this new dielectric haloscope approach. This technique could potentially search the unexplored high-frequency range of 10–100 GHz (axion mass 40–400 μeV), where traditional cavity resonators have difficulties reaching the required volume.

  14. Constraints on axion inflation from the weak gravity conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Rudelius, Tom [Jefferson Physical Laboratory, Harvard University,Cambridge, MA 02138 (United States)

    2015-09-08

    We derive constraints facing models of axion inflation based on decay constant alignment from a string-theoretic and quantum gravitational perspective. In particular, we investigate the prospects for alignment and ‘anti-alignment’ of C{sub 4} axion decay constants in type IIB string theory, deriving a strict no-go result in the latter case. We discuss the relationship of axion decay constants to the weak gravity conjecture and demonstrate agreement between our string-theoretic constraints and those coming from the ‘generalized’ weak gravity conjecture. Finally, we consider a particular model of decay constant alignment in which the potential of C{sub 4} axions in type IIB compactifications on a Calabi-Yau three-fold is dominated by contributions from D7-branes, pointing out that this model evades some of the challenges derived earlier in our paper but is highly constrained by other geometric considerations.

  15. On the robustness of cosmological axion mass limits

    CERN Document Server

    Di Valentino, Eleonora; Giusarma, Elena; Mena, Olga

    2015-01-01

    We present cosmological bounds on the thermal axion mass in an extended cosmological scenario in which the primordial power spectrum of scalar perturbations differs from the usual power-law shape predicted by the simplest inflationary models. The power spectrum is instead modeled by means of a "piecewise cubic Hermite interpolating polynomial" (PCHIP). When using Cosmic Microwave Background measurements combined with other cosmological data sets, the thermal axion mass constraints are degraded only slightly. The addition of the measurements of $\\sigma_8$ and $\\Omega_m$ from the 2013 Planck cluster catalogue on galaxy number counts relaxes the bounds on the thermal axion mass, mildly favouring a $\\sim 1$~eV axion mass, regardless of the model adopted for the primordial power spectrum.

  16. Symmetries and solutions of field equations of axion electrodynamics

    CERN Document Server

    Nikitin, A G

    2012-01-01

    The group classification of models of axion electrodynamics with arbitrary self interaction of axionic field is carried out. It is shown that extensions of the basic Poincar\\'e invariance of these models appear only for constant and exponential interactions. The related conservation laws are discussed. Using the In\\"on\\"u-Wigner contraction the non-relativistic limit of equations of axion electrodynamics is found. An extended class of exact solutions for the electromagnetic and axion fields is obtained. Among them there are solutions including up to six arbitrary functions. In particular, solutions which describe propagation with velocities faster than the velocity of light are found. These solutions are smooth and bounded functions which correspond to positive definite and bounded energy density.

  17. Dielectric Haloscopes: A New Way to Detect Axion Dark Matter

    Science.gov (United States)

    Caldwell, Allen; Dvali, Gia; Majorovits, Béla; Millar, Alexander; Raffelt, Georg; Redondo, Javier; Reimann, Olaf; Simon, Frank; Steffen, Frank; Madmax Working Group

    2017-03-01

    We propose a new strategy to search for dark matter axions in the mass range of 40 - 400 μ eV by introducing dielectric haloscopes, which consist of dielectric disks placed in a magnetic field. The changing dielectric media cause discontinuities in the axion-induced electric field, leading to the generation of propagating electromagnetic waves to satisfy the continuity requirements at the interfaces. Large-area disks with adjustable distances boost the microwave signal (10-100 GHz) to an observable level and allow one to scan over a broad axion mass range. A sensitivity to QCD axion models is conceivable with 80 disks of 1 m2 area contained in a 10 T field.

  18. Dark radiation constraints on mixed Axion/Neutralino dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Kyu Jung; Baer, Howard [Dept. of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Lessa, Andre, E-mail: bae@nhn.ou.edu, E-mail: baer@nhn.ou.edu, E-mail: lessa@fma.if.usp.br [Instituto de Física, Universidade de São Paulo, São Paulo - SP (Brazil)

    2013-04-01

    Recent analyses of CMB data combined with the measurement of BAO and H{sub 0} show that dark radiation — parametrized by the apparent number of additional neutrinos ΔN{sub eff} contributing to the cosmic expansion — is bounded from above by about ΔN{sub eff}∼<1.6 at 95% CL. We consider the mixed axion/neutralino cold dark matter scenario which arises in R-parity conserving supersymmetric (SUSY) models wherein the strong CP problem is solved by hadronic axions with a concommitant axion(a)/saxion(s)/axino(ã) supermultiplet. Our new results include improved calculations of thermal axion and saxion production and include effects of saxion decay to axinos and axions. We show that the above bound on ΔN{sub eff} is easily satisfied if saxions are mainly thermally produced and m{sub LSP} < m{sub ã}∼axions. Furthermore we show that scenarios with mixed neutralino/axion dark matter are highly constrained by combined CMB, BBN and Xe-100 constraints. In particular, supersymmetric models with a standard overabundance of neutralino dark matter are excluded for all values of the Peccei-Quinn breaking scale. Next generation WIMP direct detection experiments may be able to discover or exclude mixed axion-neutralino CDM scenarios where s → aa is the dominant saxion decay mode.

  19. Axions, Surface States, and the Post Constraint in Electromagnetics

    CERN Document Server

    Lakhtakia, Akhlesh

    2015-01-01

    After formulating the frequency-domain Maxwell equations for a homogeneous, linear, bianisotropic material occupying a bounded region, we found that the axionic piece vanishes from both the differential equations valid in the region and the boundary conditions, thereby vindicating the Post constraint. Our analysis indicates that characteristic effects that may be observed experimentally with magnetoelectric materials are not the consequences of the axionic piece but of an admittance that describes surface states.

  20. Class of Einstein-Maxwell-Dilaton-Axion Space-Times

    OpenAIRE

    2009-01-01

    We use the harmonic maps ansatz to find exact solutions of the Einstein-Maxwell-Dilaton-Axion (EMDA) equations. The solutions are harmonic maps invariant to the symplectic real group in four dimensions $Sp(4,\\Rreal)\\sim O(5)$. We find solutions of the EMDA field equations for the one and two dimensional subspaces of the symplectic group. Specially, for illustration of the method, we find space-times that generalise the Schwarzschild solution with dilaton, axion and electromagnetic fields.

  1. Instability in magnetic materials with a dynamical axion field.

    Science.gov (United States)

    Ooguri, Hirosi; Oshikawa, Masaki

    2012-04-20

    It has been pointed out that axion electrodynamics exhibits instability in the presence of a background electric field. We show that the instability leads to a complete screening of an applied electric field above a certain critical value and the excess energy is converted into a magnetic field. We clarify the physical origin of the screening effect and discuss its possible experimental realization in magnetic materials where magnetic fluctuations play the role of the dynamical axion field.

  2. Proposal for axion dark matter detection using an LC circuit.

    Science.gov (United States)

    Sikivie, P; Sullivan, N; Tanner, D B

    2014-04-04

    We show that dark matter axions cause an oscillating electric current to flow along magnetic field lines. The oscillating current induced in a strong magnetic field B0 produces a small magnetic field Ba. We propose to amplify and detect Ba using a cooled LC circuit and a very sensitive magnetometer. This appears to be a suitable approach to searching for axion dark matter in the 10(-7) to 10(-9)  eV mass range.

  3. Heavy Axion on Sark Bridge Between Higgs and Technicolor Models

    Science.gov (United States)

    Frampton, P. H.; Yanagida, T.

    It is shown how imposition of Peccei-Quinn symmetry leads to a heavy axion and strong constraints in the sark model. The axion and sark masses are derived. Analysis of chiral symmetry breaking leads to mass formulae for pseudo-Goldstone bosons; the lightest is between 44 and 125 GeV. A general picture which bridges between the sark model and a technicolor model, in terms of a new angle, is proposed.

  4. Second-generation dark-matter axion search

    Energy Technology Data Exchange (ETDEWEB)

    Sikivie, P.; Sullivan, N.S.; Tanner, D.B. [Univ. of Florida, Gainesville, FL (United States)

    1996-12-01

    This research project is a collaboration with the axion search experiment at Lawrence Livermore National Laboratory. The axion is a particle that affects two important issues in particle physics and astrophysics: the origin of CP symmetry in the strong interactions, and the composition of the dark-matter of the universe. First predicted in 1978, present laboratory, astrophysical, and cosmological constraints suggest axions have a mass in the 1 {mu}eV-1 meV range. Axions are especially significant as dark matter if their mass is in the range 1-10 {mu}eV. These dark matter axions may be detected by their coupling to photons through the E - B interaction in a tunable high-Q microwave cavity permeated by a strong external magnetic field. The present experiment is the first cavity experiment with the sensitivity to possibly observe cosmic axions. It has recently begun taking data and will operate for the next several years. The University of Florida plans to contribute to the operation of this detector and to the design and prototyping of cavities for the experiment.

  5. Searching for axions and ALPs from string theory

    CERN Document Server

    Ringwald, Andreas

    2012-01-01

    We review searches for closed string axions and axion-like particles (ALPs) in IIB string flux compactifications. For natural values of the background fluxes and TeV scale gravitino mass, the moduli stabilisation mechanism of the LARGE Volume Scenario predicts the existence of a QCD axion candidate with intermediate scale decay constant, f_a ~ 10^9 ... 10^12 GeV, associated with the small cycles wrapped by the branes hosting the visible sector, plus a nearly massless and nearly decoupled ALP associated with the LARGE cycle. In setups where the visible sector branes are wrapping more than the minimum number of two intersecting cycles, there are more ALPs which have approximately the same decay constant and coupling to the photon as the QCD axion candidate, but which are exponentially lighter. There are exciting phenomenological opportunities to search for these axions and ALPs in the near future. For f_a ~ 10^11 ... 10^12 GeV, the QCD axion can be the dominant part of dark matter and be detected in haloscopes ...

  6. A Solar Axion Search Using a Decommissioned LHC Test Magnet

    CERN Multimedia

    Raffelt, G; Lozza, V; Christensen, F E; Jakobsen, A C; Neff, S H; Dafni, T; Carmona martinez, J M; Giomataris, I; Krcmar, M; Vafeiadis, T; Luzon marco, G M; Gracia garza, J; Lakic, B; Solanki, S K; Ozbey, A; Davenport, M; Funk, W; Desch, K K; Laurent, J; Villar, J A; Jakovcic, K; Eleftheriadis, C; Cantatore, G; Diago ortega, A; Ortega ruiz, I; Papaevangelou, T; Zioutas, K; Gardikiotis, A; Cetin, S A; Hasinoff, M D; Hoffmann, D; Iguaz gutierrez, F J; Castel pablo, J F; Gninenko, S; Ferrer ribas, E; Liolios, A; Anastasopoulos, V; Kaminski, J; Garcia irastorza, I; Ruiz choliz, E; Krieger, C; Lutz, G; Fanourakis, G; Ruz armendariz, J; Vogel, J K; Pivovaroff, M J

    2002-01-01

    Previous solar axion searches have been carried out in Brookhaven (1990) and in Tokyo (2000- ), tracking the Sun with a dipole magnet. QCD inspired axions should be produced after the Big Bang, being thus candidates for the dark matter. The Sun is a very useful source of weakly interacting particles for fundamental research. Axions can be produced also in the Sun's core through the scattering of thermal photons in the Coulomb field of electric charges (Primakoff effect). In a transverse magnetic field the Primakoff effect can work in reverse, coherently converting the solar axions or other axion-like particles (ALPS) back into X-ray photons in the keV range. The conversion efficiency increases with $(B⋅L)^2$. In the CAST experiment an LHC prototype dipole magnet (B = 9 T and L = 10 m) with straight beam pipes provides a conversion efficiency exceeding that of the two earlier solar axion telescopes by almost a factor of 100. This magnet is mounted on a moving platform and coupled to both gas filled and soli...

  7. Searching for axions and ALPs from string theory

    Energy Technology Data Exchange (ETDEWEB)

    Ringwald, Andreas

    2012-09-15

    We review searches for closed string axions and axion-like particles (ALPs) in IIB string flux compactifications. For natural values of the background fluxes and TeV scale gravitino mass, the moduli stabilisation mechanism of the LARGE Volume Scenario predicts the existence of a QCD axion candidate with intermediate scale decay constant, f{sub a} {proportional_to}10{sup 9/12} GeV, associated with the small cycles wrapped by the branes hosting the visible sector, plus a nearly massless and nearly decoupled ALP associated with the LARGE cycle. In setups where the visible sector branes are wrapping more than the minimum number of two intersecting cycles, there are more ALPs which have approximately the same decay constant and coupling to the photon as the QCD axion candidate, but which are exponentially lighter. There are exciting phenomenological opportunities to search for these axions and ALPs in the near future. For f{sub a} {proportional_to}10{sup 11/12} GeV, the QCD axion can be the dominant part of dark matter and be detected in haloscopes exploiting microwave cavities. For f{sub a} {proportional_to}10{sup 9/10} GeV, the additional ALPs could explain astrophysical anomalies and be searched for in the upcoming generation of helioscopes and light-shining-through-a-wall experiments.

  8. Axion helioscopes update: the status of CAST and IAXO

    CERN Document Server

    Dafni, T.

    2014-01-01

    Almost 35 years since their suggestion as a good solution to the strong CP-problem, axions remain one of the few viable candidates for the Dark Matter, although still eluding detection. Most of the methods for their detection are based on their coupling to photons, one of the most sensitive ones being the helioscope technique. We report on the current status of the CERN Axion Solar Telescope and the future International Axion Observatory (IAXO). Recent results from the second part of CAST phase II, where the magnet bores were filled with 3He gas at variable pressure achieving sensibilities on the axion mass up to 1.2 eV, are presented. Currently, CAST is expecting to improve its sensitivity to solar axions with rest mass below 0.02 eV/c^2 after the upgrade of the X-ray detectors and with the implementation of a second X-ray optic. At the same time, it is exploring other possibilities at the low energy physics frontier. On the other hand IAXO, the fourth generation axion helioscope, aims to improve CAST's perf...

  9. The Superconducting Toroid for the New International AXion Observatory (IAXO)

    CERN Document Server

    Shilon, I; Silva, H; Wagner, U; Kate, H H J ten

    2013-01-01

    IAXO, the new International AXion Observatory, will feature the most ambitious detector for solar axions to date. Axions are hypothetical particles which were postulated to solve one of the puzzles arising in the standard model of particle physics, namely the strong CP (Charge conjugation and Parity) problem. This detector aims at achieving a sensitivity to the coupling between axions and photons of one order of magnitude beyond the limits of the current detector, the CERN Axion Solar Telescope (CAST). The IAXO detector relies on a high-magnetic field distributed over a very large volume to convert solar axions to detectable X-ray photons. Inspired by the ATLAS barrel and end-cap toroids, a large superconducting toroid is being designed. The toroid comprises eight, one meter wide and twenty one meters long racetrack coils. The assembled toroid is sized 5.2 m in diameter and 25 m in length and its mass is about 250 tons. The useful field in the bores is 2.5 T while the peak magnetic field in the windings is 5....

  10. Supersymmetric axion grand unified theories and their predictions

    Science.gov (United States)

    Co, Raymond T.; D'Eramo, Francesco; Hall, Lawrence J.

    2016-10-01

    We introduce a class of unified supersymmetric axion theories with unified and Peccei-Quinn (PQ) symmetries broken by the same set of fields at a scale ˜2 ×1 016 GeV . A typical domain wall number of order 30 leads to an axion decay constant fa of order 1 015 GeV . Inflation generates a large saxion condensate, giving a reheat temperature TR below the QCD scale for supersymmetry breaking of order 1-10 TeV. Axion field oscillations commence in the saxion matter-dominated era near the QCD scale, and recent lattice computations of the temperature dependence of the axion mass in this era allow a controlled calculation of the axion dark matter abundance. The observed abundance can be successfully explained by an initial axion misalignment angle of order unity, θi˜1 . A highly correlated set of predictions is discussed for fa, TR, the supersymmetric Higgs mass parameter μ , the amount of dark radiation Δ Neff, the proton decay rate Γ (p →e+π0), isocurvature density perturbations and the B mode of the cosmic microwave background. The last two are particularly interesting when the energy scale of inflation is also of order 1 016 GeV .

  11. Axion-photon Propagation in Magnetized Universe

    CERN Document Server

    Wang, Chen

    2015-01-01

    Oscillations between photons and axion-like particles (ALP) travelling in intergalactic magnetic fields have been invoked to explain a number of astrophysical phenomena, or used to constrain ALP properties using observations. One example is the anomalous transparency of the universe to TeV gamma-rays. The intergalactic magnetic field is usually modeled as patches of coherent domains, each with a uniform magnetic field, but the field orientation changes randomly from one domain to the next ("discrete-$\\varphi$ model"). We show in this paper that in more realistic situations, when the magnetic field direction varies continuously along the propagation path, the photon-to-ALP conversion probability $P$ can be significantly different from the discrete-$\\varphi$ model. In particular, $P$ has a distinct dependence on the photon energy and ALP mass, and can be as large as 100 percent. This result may affect previous constraints on ALP properties based on ALP-photon propagation in intergalactic magnetic fields.

  12. Anisotropic plasmas from axion and dilaton deformations

    CERN Document Server

    Donos, Aristomenis; Sosa-Rodriguez, Omar

    2016-01-01

    We construct black hole solutions of type IIB supergravity that are holographically dual to anisotropic plasmas arising from deformations of an infinite class of four-dimensional CFTs. The CFTs are dual to $AdS_5\\times X_5$, where $X_5$ is an Einstein manifold, and the deformations involve the type IIB axion and dilaton, with non-trivial periodic dependence on one of the spatial directions of the CFT. At low temperatures the solutions approach smooth domain wall solutions with the same $AdS_5\\times X_5$ solution appearing in the far IR. For sufficiently large deformations an intermediate scaling regime appears which is governed by a Lifshitz-like scaling solution. We calculate the DC thermal conductivity and some components of the shear viscosity tensor.

  13. Minimal models for axion and neutrino

    Directory of Open Access Journals (Sweden)

    Y.H. Ahn

    2016-01-01

    Full Text Available The PQ mechanism resolving the strong CP problem and the seesaw mechanism explaining the smallness of neutrino masses may be related in a way that the PQ symmetry breaking scale and the seesaw scale arise from a common origin. Depending on how the PQ symmetry and the seesaw mechanism are realized, one has different predictions on the color and electromagnetic anomalies which could be tested in the future axion dark matter search experiments. Motivated by this, we construct various PQ seesaw models which are minimally extended from the (non- supersymmetric Standard Model and thus set up different benchmark points on the axion–photon–photon coupling in comparison with the standard KSVZ and DFSZ models.

  14. Bifid Throats for Axion Monodromy Inflation

    Energy Technology Data Exchange (ETDEWEB)

    Retolaza, Ander [Univ. Autonoma de Madrid (Spain). Inst. de Fisica Teorica IFT-UAM/CSIC; Universidad Autonoma de Madrid (Spain). Dept. de Fisica Teorica; Uranga, Angel M. [Univ. Autonoma de Madrid (Spain). Inst. de Fisica Teorica IFT-UAM/CSIC; Westphal, Alexander [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-04-15

    We construct a simple explicit local geometry providing a 'bifid throat' for 5-brane axion monodromy. A bifid throat is a throat that splits into two daughter throats in the IR, containing a homologous 2-cycle family reaching down into each daughter throat. Our example consists of a deformed Z{sub 3} x Z{sub 2} orbifold of the conifold, which provides us with an explicit holographic dual of the bifid throat including D3-branes and fractional 5-branes at the toric singularities of our setup. Having the holographic description in terms of the dual gauge theory allows us to address the effect of 5-brane-antibrane pair backreaction including the warping effects. This leads to the size of the backreaction being small and controllable after imposing proper normalization of the inflaton potential and hence the warping scales.

  15. Anisotropic plasmas from axion and dilaton deformations

    Science.gov (United States)

    Donos, Aristomenis; Gauntlett, Jerome P.; Sosa-Rodriguez, Omar

    2016-11-01

    We construct black hole solutions of type IIB supergravity that are holographically dual to anisotropic plasmas arising from deformations of an infinite class of four-dimensional CFTs. The CFTs are dual to AdS 5 × X 5, where X 5 is an Einstein manifold, and the deformations involve the type IIB axion and dilaton, with non-trivial periodic dependence on one of the spatial directions of the CFT. At low temperatures the solutions approach smooth domain wall solutions with the same AdS 5 × X 5 solution appearing in the far IR. For sufficiently large deformations an intermediate scaling regime appears which is governed by a Lifshitz-like scaling solution. We calculate the DC thermal conductivity and some components of the shear viscosity tensor.

  16. Can gravitational instantons really constrain axion inflation?

    Science.gov (United States)

    Hebecker, Arthur; Mangat, Patrick; Theisen, Stefan; Witkowski, Lukas T.

    2017-02-01

    Axions play a central role in inflationary model building and other cosmological applications. This is mainly due to their flat potential, which is protected by a global shift symmetry. However, quantum gravity is known to break global symmetries, the crucial effect in the present context being gravitational instantons or Giddings-Strominger wormholes. We attempt to quantify, as model-independently as possible, how large a scalar potential is induced by this general quantum gravity effect. We pay particular attention to the crucial issue which solutions can or cannot be trusted in the presence of a moduli-stabilisation and a Kaluza-Klein scale. An important conclusion is that, due to specific numerical prefactors, the effect is surprisingly small even in UV-completions with the highest possible scale offered by string theory.

  17. Dilaton and axion bremsstrahlung from collisions of cosmic (super)strings

    CERN Document Server

    Melkumova, E Y; Salehi, K

    2007-01-01

    We calculate dilaton and axion radiation generated in the collision of two straight initially unexcited strings and give a rough cosmological estimate of dilaton and axion densities produced via this mechanism in the early universe.

  18. Dilaton and axion bremsstrahlung from collisions of cosmic (super)strings

    OpenAIRE

    Melkumova, E. Yu.; Gal'tsov, D. V.; Salehi, K.

    2006-01-01

    We calculate dilaton and axion radiation generated in the collision of two straight initially unexcited strings and give a rough cosmological estimate of dilaton and axion densities produced via this mechanism in the early universe.

  19. Cosmic axion background propagation in galaxies

    Directory of Open Access Journals (Sweden)

    Francesca V. Day

    2016-02-01

    Full Text Available Many extensions of the Standard Model include axions or axion-like particles (ALPs. Here we study ALP to photon conversion in the magnetic field of the Milky Way and starburst galaxies. By modelling the effects of the coherent and random magnetic fields, the warm ionized medium and the warm neutral medium on the conversion process, we simulate maps of the conversion probability across the sky for a range of ALP energies. In particular, we consider a diffuse cosmic ALP background (CAB analogous to the CMB, whose existence is suggested by string models of inflation. ALP–photon conversion of a CAB in the magnetic fields of galaxy clusters has been proposed as an explanation of the cluster soft X-ray excess. We therefore study the phenomenology and expected photon signal of CAB propagation in the Milky Way. We find that, for the CAB parameters required to explain the cluster soft X-ray excess, the photon flux from ALP–photon conversion in the Milky Way would be unobservably small. The ALP–photon conversion probability in galaxy clusters is 3 orders of magnitude higher than that in the Milky Way. Furthermore, the morphology of the unresolved cosmic X-ray background is incompatible with a significant component from ALP–photon conversion. We also consider ALP–photon conversion in starburst galaxies, which host much higher magnetic fields. By considering the clumpy structure of the galactic plasma, we find that conversion probabilities comparable to those in clusters may be possible in starburst galaxies.

  20. GammeV: Fermilab axion-like particle photon regeneration results

    Energy Technology Data Exchange (ETDEWEB)

    Wester, William; /Fermilab

    2008-09-01

    GammeV is an axion-like particle photon regeneration experiment conducted at Fermilab that employs the light shining through a wall technique. They obtain limits on the coupling 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. They are able to exclude the axion-like particle interpretation of the anomalous PVLAS 2006 result by more than 5 standard deviations.

  1. Does Divisional Play Lead to More Pennant Races?

    OpenAIRE

    Wayne Winston; Ashok Soni

    1982-01-01

    A "pennant race" occurs in a sports league if the top two teams in a league finish within m\\bar games of each other. We develop an analytical model that can be used to predict the probability that a sports league will have a pennant race. The model is then tested on data from the last 50 major league baseball seasons and is shown to do a remarkable job of predicting the number of pennant races that actually occurred. Finally, we give conditions which ensure that dividing a league of 2n teams ...

  2. Searching for an Axion-like Particle at the Large Hadron Collider

    CERN Document Server

    Coriano, Claudio; Mariano, Antonio

    2009-01-01

    Axion-like particles are an important part of the spectrum of anomalous gauge theories involving modified mechanisms of cancellation of the gauge anomalies. Among these are intersecting brane models, which are characterized by the presence of one physical axion. We overview a recent study of their supersymmetric construction and some LHC studies of the productions rates for a gauged axion.

  3. CP-Conservation in QCD and why only "invisible" Axions work

    CERN Document Server

    Kim, Jihn E

    2016-01-01

    Among solutions of the strong CP problem, the "invisible" axion in the narrow axion window is argued to be the remaining possibility among natural solutions on the smallness of $\\bar{\\theta}$. Related to the gravity spoil of global symmetries, some prospective invisible axions from theory point of view are discussed. In all these discussions, including the observational possibility, cosmological constraints must be included.

  4. Propagation of converted solar axions inside the surface cool plasma

    Science.gov (United States)

    Zioutas, K.; Tsagri, M.; Semertzidis, Y.; Papaevangelou, Th.

    2009-04-01

    Under certain conditions of solar plasma density, magnetic field and eventually field gradient, axions or other exotica with similar properties can be converted back to hard X-rays as they stream out of the hot solar core. A GEANT4 simulation was performed for the propagation of ~1-10 keV photons in a relatively cool plasma, some 100 km below the solar surface. Due to multiple Compton scattering, the photon's random path depends sensitively on the actual depth of the axion-to-photon conversion place, where the otherwise unexpected X-rays are assumed to be emitted radially outwards. This results to a continuous non-linear energy degradation of the converted solar axion energy spectrum: an initially wide and hard X-ray spectrum is being continuously redshifted into an exponential form, whose steepness (i.e., the power law index) critically depends on the plasma column density above the place of conversion. In addition, an initial pencil-like beam of hard X-rays, when escaping from the solar surface gives rise to a characteristic wide spot (e.g., some Mm). Thus, the measured shape of the energy spectrum, the spatial extension of the outstreaming X-rays, etc., can be regarded (individually or combined) as novel signatures of the solar axion particle ID. If plasma resonance effects are at work for the enhanced conversion to occur, a comparison with X-ray observations from the flaring Sun results, within the axion(-like) scenario, to a rest mass of m_axion ~10 [meV]. We note that the Monte Carlo results of this work are conventional in nature. Only the origin of the suddenly appearance of X-rays has been motivated by axions or the like. Further reading: http://xxx.lanl.gov/ftp/arxiv/papers/0808/0808.1545.pdf

  5. Record Participation in the Relay Race!

    CERN Multimedia

    2002-01-01

    CERN has a more sporting spirit than ever before. This is not the result of any survey, but the impression you got as soon as you saw the 62 teams of six runners each speeding around the laboratory in the 32nd annual relay race. This year 11 more teams competed than in 2001.   First changeover: Hervé Cornet takes over from Camille Ruiz Llamas for The Shabbys, and Sebastian Dorthe from Daniel Matteazzi for Charmilles Technologies. Jérôme Bendotti (EP/TA1) just holding off the team from the WHO at the finish. A total of 372 people ran together last Wednesday in this year's relay race, making for a record participation. It also seems that women are becoming more and more attracted by this competition, since this year there were eight ladies teams, also a new record. The first team were The Shabbys in a time of 10 minutes 45 seconds, finishing almost before the second team had started its last 300 metre leg. The 6 runners in each team cover distances of 1000, 800, 800,...

  6. Some theoretical and experimental aspects of axion physics

    CERN Document Server

    Renau, Albert

    2015-01-01

    In the first part of the thesis, we revisit the Dine-Fischler-Srednicki-Zhitnisky axion model in light of the recent Higgs LHC results and electroweak precision data. This model is an extension of the two-Higgs-doublet model incorporating a PQ symmetry which leads to a physically acceptable axion. For generic values of the couplings, the model reproduces the minimal Standard Model, with a massless axion and all the other degrees of freedom at a very high scale. However, in some scenarios, the extra Higgses could be relatively light. We use the oblique corrections, in particular $\\Delta\\rho$, to constrain the mass spectrum in this case. Finally, we also work out the non-linear parametrization of the DFSZ model in the generic case where all scalars except the lightest Higgs and the axion have masses at or beyond the TeV scale. In the second part, we study the relevance of a cold axion background (CAB) as a responsible for the dark matter in the Universe and examine its consequences through its effects on photon...

  7. Tracking Dark Energy from Axion-Gauge Field Couplings

    CERN Document Server

    Alexander, Stephon; Froehlich, Juerg

    2016-01-01

    We propose a model of Dark Energy in which the field currently dominating the energy density of the universe is an "axion field" linearly coupled to the Pontryagin density, $ \\text{tr}(F \\wedge F)$, (i.e., the exterior derivative of the Chern-Simons form) of a massive gauge field. We assume that the axion has self-interactions corresponding to a non-trivial (exponential) potential. We argue that a non-vanishing magnetic helicity of the gauge field triggers slow-rolling of the axion at field values far below the Planck scale. Our proposal leads to a "Tracking Dark Energy Scenario" in which the contribution of the axion energy density to the total energy density is constant (and small) during the early radiation phase, until a secular growth term proportional to the Pontryagin density of the gauge field becomes dominant. The initially small contribution of the axion field to the total energy density is related to the observed small baryon-to-entropy ratio. Some speculations concerning the nature of the gauge fi...

  8. New solar axion search in CAST with $^4$He filling

    CERN Document Server

    Arik, M; Barth, K; Belov, A; Brauninger, H; Bremer, J; Burwitz, V; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Da Riva, E; Dafni, T; Davenport, M; Dermenev, A; Eleftheriadis, C; Elias, N; Fanourakis, G; Ferrer-Ribas, E; Galan, J; Garcia, J A; Gardikiotis, A.; Garza, J G; Gazis, E N; Geralis, T; Georgiopoulou, E; Giomataris, I; Gninenko, S; Marzoa, M Gomez; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; K.Jakovcic; Karuza, M; Kavuk, M; Krcmar, M; Kuster, M; Lakic, B; Laurent, J M; Liolios, A; Ljubicic, A; Luzon, G; Neff, S; Niinikoski, T; Nordt, A; Ortega, I; Papaevangelou, T; Pivovaroff, M .J; Raffelt, G; Rodriguez, A; Rosu, M; Ruz, J; Savvidis, I; Shilon, I; Solanki, S K; Stewart, L; Tomas, A; Vafeiadis, T; Villar, J; Vogel, J K; Yildiz, S C; Zioutas, K

    2015-01-01

    The CERN Axion Solar Telescope (CAST) searches for $a\\to\\gamma$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. Two parallel magnet bores can be filled with helium of adjustable pressure to match the X-ray refractive mass $m_\\gamma$ to the axion search mass $m_a$. After the vacuum phase (2003--2004), which is optimal for $m_a\\lesssim0.02$ eV, we used $^4$He in 2005--2007 to cover the mass range of 0.02--0.39 eV and $^3$He in 2009--2011 to scan from 0.39--1.17 eV. After improving the detectors and shielding, we returned to $^4$He in 2012 to investigate a narrow $m_a$ range around 0.2 eV ("candidate setting" of our earlier search) and 0.39--0.42 eV, the upper axion mass range reachable with $^4$He, to "cross the axion line" for the KSVZ model. We have improved the limit on the axion-photon coupling to $g_{a\\gamma}< 1.47\\times10^{-10} {\\rm GeV}^{-1}$ (95% C.L.), depending on the pressure settings. Since 2013, we have returned to vacuum and aim for a s...

  9. Cosmic D-strings as Axionic D-term Strings

    CERN Document Server

    Blanco-Pillado, J J; Redi, M; Blanco-Pillado, Jose J.; Dvali, Gia; Redi, Michele

    2005-01-01

    In this work we derive non-singular BPS string solutions from an action that captures the essential features of a D-brane-anti-D-brane system compactified to four dimensions. The model we consider is a supersymmetric abelian Higgs model with a D-term potential coupled to an axion-dilaton multiplet. The strings in question are axionic D-term strings which we identify with the D-strings of type II string theory. In this picture the Higgs field represents the open string tachyon of the D-Dbar pair and the axion is dual to a Ramond Ramond form. The crucial term allowing the existence of non-singular BPS strings is the Fayet-Iliopoulos term, which is related to the tensions of the D-string and of the parent branes. Despite the presence of the axion, the strings are BPS and carry finite energy, due to the fact that the space gets very slowly decompactified away from the core, screening the long range axion field (or equivalently the theory approaches an infinitely weak 4D coupling). Within our 4D effective action w...

  10. Axions and the pulsation periods of variable white dwarfs revisited

    CERN Document Server

    Isern, J; Althaus, L G; Córsico, A H

    2010-01-01

    Axions are the natural consequence of the introduction of the Peccei-Quinn symmetry to solve the strong CP problem. All the efforts to detect such elusive particles have failed up to now. Nevertheless, it has been recently shown that the luminosity function of white dwarfs is best fitted if axions with a mass of a few meV are included in the evolutionary calculations. Our aim is to show that variable white dwarfs can provide additional and independent evidence about the existence of axions. The evolution of a white dwarf is a slow cooling process that translates into a secular increase of the pulsation periods of some variable white dwarfs, the so-called DAV and DBV types. Since axions can freely escape from such stars, their existence would increase the cooling rate and, consequently, the rate of change of the periods as compared with the standard ones. The present values of the rate of change of the pulsation period of G117-B15A are compatible with the existence of axions with the masses suggested by the lu...

  11. Axion dark matter, solitons, and the cusp-core problem

    CERN Document Server

    Marsh, David J E

    2015-01-01

    Self-gravitating bosonic fields can support stable and localised field configurations. For real fields, these solutions oscillate in time and are known as oscillatons. The density profile is static, and is soliton. Such solitons should be ubiquitous in models of axion dark matter, with the soliton characteristic mass and size depending on some inverse power of the axion mass. Stable configurations of non-relativistic axions are studied numerically using the Schr\\"{o}dinger-Poisson system. This method, and the resulting soliton density profiles, are reviewed. Using a scaling symmetry and the uncertainty principle, the core size of the soliton can be related to the central density and axion mass, $m_a$, in a universal way. Solitons have a constant central density due to pressure-support, unlike the cuspy profile of cold dark matter (CDM). One consequence of this fact is that solitons composed of ultra-light axions (ULAs) may resolve the `cusp-core' problem of CDM. In DM halos, thermodynamics will lead to a CDM-...

  12. The Race Race: Assimilation in America

    Science.gov (United States)

    Balis, Andrea; Aman, Michael

    2013-01-01

    Can race and assimilation be taught? Interdisciplinary pedagogy provides a methodology, context, and use of nontraditional texts culled from American cultural history such as from, theater and historical texts. This approach and these texts prove useful for an examination of race and assimilation in America. The paper describes a course that while…

  13. A SQUID-based microwave cavity search for dark-matter axions

    Energy Technology Data Exchange (ETDEWEB)

    Asztalos, S J; Carosi, G; Hagmann, C; Kinion, D; van Bibber, K; Hotz, M; Rosenberg, L; Rybka, G; Hoskins, J; Hwang, J; Sikivie, P; Tanner, D B; Bradley, R; Clarke, J

    2009-10-21

    Axions in the {mu}eV mass range are a plausible cold dark matter candidate and may be detected by their conversion into microwave photons in a resonant cavity immersed in a static magnetic field. The first result from such an axion search using a superconducting first-stage amplifier (SQUID) is reported. The SQUID amplifier, replacing a conventional GaAs field-effect transistor amplifier, successfully reached axion-photon coupling sensitivity in the band set by present axion models and sets the stage for a definitive axion search utilizing near quantum-limited SQUID amplifiers.

  14. Excess astrophysical photons from a 0.1-1 keV cosmic axion background.

    Science.gov (United States)

    Conlon, Joseph P; Marsh, M C David

    2013-10-11

    Primordial decays of string theory moduli at z~10(12) naturally generate a dark radiation cosmic axion background with 0.1-1 keV energies. This cosmic axion background can be detected through axion-photon conversion in astrophysical magnetic fields to give quasithermal excesses in the extreme ultraviolet and soft x-ray bands. Substantial and observable luminosities may be generated even for axion-photon couplings axion-photon conversion may explain the observed excess emission of soft x rays from galaxy clusters, and may also contribute to the diffuse unresolved cosmic x-ray background. We list a number of correlated predictions of the scenario.

  15. Race to the Top

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The global race in developing and deploying green energy technology can be a win-win game "Clean energy race" has become a catchphrase for journalists and bloggers to attract reader eyes. Googling that, one will be

  16. Bridged Race Population Estimates

    Data.gov (United States)

    U.S. Department of Health & Human Services — Population estimates from "bridging" the 31 race categories used in Census 2000, as specified in the 1997 Office of Management and Budget (OMB) race and ethnicity...

  17. Pierre Sikivie from the University of Florida invented the working principle of all magnetic axion telescopes, such as CAST.

    CERN Multimedia

    Claudia Marcelloni

    2006-01-01

    The possible existence of axions in the universe means that they are a candidate for (very) cold dark matter, as another axion pioneer, Pierre Sikivie, from the University of Florida explained during the first Joint ILIAS-CAST-CERN Axion Training workshop. He also described the technique that he invented in 1983 for detecting axions. The idea is that axions in the galactic halo may be resonantly converted to microwave photons in a cavity permeated by a strong magnetic field.

  18. Team Learning Ditinjau dari Team Diversity dan Team Efficacy

    OpenAIRE

    Vivi Gusrini Rahmadani Pohan; Djamaludin Ancok

    2015-01-01

    This research attempted to observe team learning from the level of team diversity and team efficacy of work teams. This research used an individual level of analysis rather than the group level. The team members measured the level of team diversity, team efficacy and team learning of the teams through three scales, namely team learning scale, team diversity scale, and team efficacy scale. Respondents in this research were the active team members in a company, PT. Alkindo Mitraraya. The total ...

  19. Constraining axion coupling constants from measuring the Casimir interaction between polarized test bodies

    Science.gov (United States)

    Bezerra, V. B.; Klimchitskaya, G. L.; Mostepanenko, V. M.; Romero, C.

    2016-08-01

    We propose an experiment for measuring the effective Casimir pressure between two parallel silicon carbide (SiC) plates with aligned nuclear spins. The prospective constraints on an axion-neutron coupling constant for both hadronic and grand unified theory (GUT) axions are calculated using the process of one-axion exchange. For this purpose, a general expression for the additional pressure arising between two polarized plates due to the exchange of one axion between their constituent fermions is derived. We demonstrate that only the polarization component perpendicular to the plates contributes to the pressure. The obtained pressure can be both repulsive and attractive depending on whether the polarizations of both plates are unidirectional or directed in opposite directions. It is shown that although the constraints on an axion-electron coupling obtained in the case of magnetized plates are not competitive, the constraints on an axion-neutron coupling found for plates with polarized nuclear spins are of the same order of magnitude as those obtained previously for the GUT axions alone using the process of two-axion exchange. The proposed experiment allows us also to strengthen the presently known constraints on the axion-neutron coupling constants of GUT axions by using both processes of one- and two-axion exchange.

  20. Searching for galactic axions through magnetized media: the QUAX proposal

    CERN Document Server

    Barbieri, R; Carugno, G; Gallo, C S; Lombardi, A; Ortolan, A; Pengo, R; Ruoso, G; Speake, C C

    2016-01-01

    We present a proposal to search for QCD axions with mass in the 100 $\\mu$eV range, assuming that they make a dominant component of dark matter. Due to the axion-electron spin coupling, their effect is equivalent to the application of an oscillating rf field with frequency and amplitude fixed by the axion mass and coupling respectively. This equivalent magnetic field would produce spin flips in a magnetic sample placed inside a static magnetic field, which determines the resonant interaction at the Larmor frequency. Spin flips would subsequently emit radio frequency photons that can be detected by a suitable quantum counter in an ultra-cryogenic environment. This new detection technique is crucial to keep under control the thermal photon background which would otherwise produce a too large noise.

  1. Searching for galactic axions through magnetized media: The QUAX proposal

    Science.gov (United States)

    Barbieri, R.; Braggio, C.; Carugno, G.; Gallo, C. S.; Lombardi, A.; Ortolan, A.; Pengo, R.; Ruoso, G.; Speake, C. C.

    2017-03-01

    We present a proposal to search for QCD axions with mass in the 200 μeV range, assuming that they make a dominant component of dark matter. Due to the axion-electron spin coupling, their effect is equivalent to the application of an oscillating rf field with frequency and amplitude fixed by the axion mass and coupling respectively. This equivalent magnetic field would produce spin flips in a magnetic sample placed inside a static magnetic field, which determines the resonant interaction at the Larmor frequency. Spin flips would subsequently emit radio frequency photons that can be detected by a suitable quantum counter in an ultra-cryogenic environment. This new detection technique is crucial to keep under control the thermal photon background which would otherwise produce a too large noise.

  2. Gravity Waves and Linear Inflation From Axion Monodromy

    Energy Technology Data Exchange (ETDEWEB)

    McAllister, Liam; /Cornell U., LEPP /Cornell U., Phys. Dept.; Silverstein, Eva; Westphal, Alexander; /SLAC /Stanford U., Phys. Dept.

    2010-08-26

    Wrapped branes in string compactifications introduce a monodromy that extends the field range of individual closed-string axions to beyond the Planck scale. Furthermore, approximate shift symmetries of the system naturally control corrections to the axion potential. This suggests a general mechanism for chaotic inflation driven by monodromy-extended closed-string axions. We systematically analyze this possibility and show that the mechanism is compatible with moduli stabilization and can be realized in many types of compactifications, including warped Calabi-Yau manifolds and more general Ricci-curved spaces. In this broad class of models, the potential is linear in the canonical inflaton field, predicting a tensor to scalar ratio r {approx} 0.07 accessible to upcoming cosmic microwave background (CMB) observations.

  3. A Bump in the Blue Axion Isocurvature Spectrum

    CERN Document Server

    Chung, Daniel J H

    2016-01-01

    Blue axion isocurvature perturbations are both theoretically well-motivated and interesting from a detectability perspective. These power spectra generically have a break from the blue region to a flat region. Previous investigations of the power spectra were analytic, which left a gap in the predicted spectrum in the break region due to the non-applicability of the used analytic techniques. We therefore compute the isocurvature spectrum numerically for an explicit supersymmetric axion model. We find a bump that enhances the isocurvature signal for this class of scenarios. A fitting function of three parameters is constructed that fits the spectrum well for the particular axion model we study. This fitting function should be useful for blue isocurvature signal hunting in data and making experimental sensitivity forecasts.

  4. CrossRef The CERN Axion Solar Telescope

    CERN Document Server

    Hasinoff, M D; Arik, E; Autiero, D; Avignone, F; Barth, K; Bingol, E; Brauninger, H; Brodzinski, R; Carmona, J; Chesi, E; Cebrian, S; Cetin, S; Collar, J; Creswick, R; Dafni, T; De Oliveira, R; Dedoussis, S; Delbart, A; Di Lella, L; Eleftheriadis, C; Fanourakis, G; Farach, H; Fischer, H; Formenti, F; Geralis, T; Giomataris, I; Gninenko, S; Goloubev, N; Hartmann, R; Hoffmann, D; Irastorza, I G; Jacoby, J; Kang, D; Konigsmann, K; Kotthaus, R; Krcmar, M; Kuster, M; Lakic, B; Liolios, A; LJubicic, A; Lutz, G; Luzon, G; Miley, H; Morales, A; Morales, J; Mutterer, M; Nikolaidis, A; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, G; Riege, H; Sarsa, M; Savvidis, I; Schopper, R; Semertzidis, I; Spano, C; Villar, J; Vullierme, B; Walckiers, L; Zachariadou, K; Zioutas, K

    2003-01-01

    The CAST experiment at CERN is using a decommissioned LHC prototype magnet to search for solar axions through their Primakoff conversion into x-ray photons. The magnet (B = 9.0 Tesla, L = 10 m) can track the sun each day for a total exposure time of ~180 minutes (sunrise + sunset). We expect to reach a sensitivity in axion-photon coupling, gaγγ ≲ 5 × 10-11 GeV-1 for ma ≲ 10-2 eV after ˜1 year's running time. By filling the beam tube with 4He or 3He gas we should be able to extend the sensitive axion mass region into the eV mass range.

  5. Axion-Assisted Production of Sterile Neutrino Dark Matter

    CERN Document Server

    Berlin, Asher

    2016-01-01

    Sterile neutrinos can be generated in the early universe through oscillations with active neutrinos and represent a popular and well-studied candidate for our universe's dark matter. Stringent constraints from X-ray and gamma-ray line searches, however, have excluded the simplest of such models. In this letter, we propose a novel alternative to the standard scenario in which the mixing angle between the sterile and active neutrinos is a dynamical quantity, induced through interactions with a light axion-like field. As the energy density of the axion-like particles is diluted by Hubble expansion, the degree of mixing is reduced at late times, suppressing the decay rate and easily alleviating any tension with X-ray or gamma-ray constraints. We present a simple model which illustrates the phenomenology of this scenario, and also describe a framework in which the QCD axion is responsible for the production of sterile neutrinos in the early universe.

  6. Leptogenesis from Left-Handed Neutrino Production during Axion Inflation.

    Science.gov (United States)

    Adshead, Peter; Sfakianakis, Evangelos I

    2016-03-04

    We propose that the observed matter-antimatter asymmetry can be naturally produced as a by-product of axion-driven slow-roll inflation by coupling the axion to standard model neutrinos. We assume that grand unified theory scale right-handed neutrinos are responsible for the masses of the standard model neutrinos and that the Higgs field is light during inflation and develops a Hubble-scale root-mean-square value. In this setup, the rolling axion generates a helicity asymmetry in standard model neutrinos. Following inflation, this helicity asymmetry becomes equal to a net lepton number as the Higgs condensate decays and is partially reprocessed by the SU(2)_{L} sphaleron into a net baryon number.

  7. Relaxing isocurvature bounds on string axion dark matter

    Directory of Open Access Journals (Sweden)

    Masahiro Kawasaki

    2014-10-01

    Full Text Available If inflation scale is high, light scalars acquire large quantum fluctuations during inflation. If sufficiently long-lived, they will give rise to CDM isocurvature perturbations, which are highly constrained by the Planck data. Focusing on string axions as such light scalars, we show that thermal inflation can provide a sufficiently large entropy production to dilute the CDM isocurvature perturbations. Importantly, efficient dilution is possible for the string axions, because effectively no secondary coherent oscillations are induced at the end of thermal inflation, in contrast to the moduli fields. We also study the viability of the axion dark matter with mass of about 7 keV as the origin of the 3.5 keV X-ray line excess, in the presence of large entropy production.

  8. Solar Axion Search Technique with Correlated Signals from Multiple Detectors

    CERN Document Server

    Xu, Wenqin

    2016-01-01

    The coherent Bragg scattering of solar axions inside crystals would boost the signal for axion-photon coupling enhancing experimental sensitivity for these hypothetical particles. Knowledge of the scattering angle of solar axions with respect to the crystal lattice is required to make theoretical predications of signal strength. Hence, both the lattice axis angle within a crystal and the absolute angle between the crystal and the Sun must be known. In this paper, we demonstrate that, in a multiple-crystal setup, knowledge of the relative axis orientation between multiple crystals can improve the experimental sensitivity, or equivalently, relax the precision on the absolute solar angle measurement. However, if absolute angles of all crystal axes are measured, we find that a precision of 2 degrees to 4 degrees will suffice. Finally, we also show that, given a minimum number of detectors, a signal model averaged over angles can substitute for precise crystal angular measurements, with some loss of sensitivity.

  9. Couplings between QCD axion and photon from string compactification

    Directory of Open Access Journals (Sweden)

    Jihn E. Kim

    2016-08-01

    Full Text Available The QCD axion couplings of various invisible axion models are presented. In particular, the exact global symmetry U(1PQ in the superpotential is possible for the anomalous U(1 from string compactification, broken only by the gauge anomalies at one loop level, and is shown to have the resultant invisible axion coupling to photon, caγγ≥83−caγγchbr where caγγchbr≃2. However, this bound is not applicable in approximate U(1PQ models with sufficiently suppressed U(1PQ-breaking superpotential terms. We also present a simple method to obtain caγγ0 which is the value obtained above the electroweak scale.

  10. Backreaction Issues in Axion Monodromy and Minkowski 4-forms

    CERN Document Server

    Valenzuela, Irene

    2016-01-01

    We clarify the differences between the usual Kaloper-Sorbo description of axion monodromy and the effective axionic potential in terms of Minkowski 4-forms derived in string compactifications. The fact that the metric of the 3-form fields coming from string theory is field dependent (unlike in Kaloper-Sorbo) leads to the backreaction issues recently studied in axion monodromy models within string theory. We reanalyse these problems in terms of the 4-forms focusing on the case in which the non-periodic scalars backreact on the Kahler metric of the inflaton reducing the physical field range. In the closed string sector of Type II Calabi-Yau compactifications with fluxes the metric becomes field dependent precisely when $\\Delta\\phi\\sim M_p$, independently of the choice of fluxes. We propose, however, some counter-examples to this universal behaviour by including open string fields.

  11. Leptogenesis from left-handed neutrino production during axion inflation

    CERN Document Server

    Adshead, Peter

    2015-01-01

    We propose that the observed matter-antimatter asymmetry can be naturally produced as a byproduct of axion-driven slow-roll inflation by coupling the axion to standard-model neutrinos. We assume that GUT scale right-handed neutrinos are responsible for the masses of the standard model neutrinos and that the Higgs is a light field during inflation and develops a Hubble scale vacuum expectation value (VEV). In this set up, the rolling axion generates a helicity asymmetry in standard-model neutrinos. Following inflation, this helicity asymmetry becomes equal to a net lepton number as the Higgs VEV decays and is partially re-processed by the $SU(2)_{L}$ sphaleron into a net baryon number.

  12. Management Teams

    CERN Document Server

    Belbin, R Meredith Meredith

    2012-01-01

    Meredith Belbin's work on teams has become part of everyday language in organizations all over the world. All kinds of teams and team behaviours are covered. At the end of the book is a self-perception inventory so that readers can match their own personalities to particular team roles. Management Teams is required reading for managers concerned with achieving results by getting the best from their key personnel.

  13. Can the dark matter halo be a collisionless ensemble of axion stars?

    CERN Document Server

    Barranco, J; Delepine, D

    2012-01-01

    If dark matter is mainly composed of axions, the density distribution can be non uniform distributed but clumpy instead. By solving the Einstein-Klein Gordon system of a scalar field with a potential energy density of an axion like particle, we obtain the maximum mass of the self gravitating system made of axions called axion stars. The collision of axion stars with neutron stars may release the energy of axions due to the conversion of axions into photons in the presence of the neutron star magnetic field. We estimate the energy release and shown that it may exceed the solar luminosity per collision but should be much less than previous estimates. Future data from femtolensing should strongly constrain this scenario.

  14. On the 3-form formulation of axion potentials from D-brane instantons

    CERN Document Server

    García-Valdecasas, Eduardo

    2016-01-01

    The study of axion models and quantum corrections to their potential has experienced great progress by phrasing the axion potential in terms of a 3-form field eating up the 2-form field dual to the axion. Such reformulation of the axion potential has been described for axion monodromy models, and for axion potentials from non-perturbative gauge dynamics. In this paper we propose a 3-form description of the axion potentials from non-gauge D-brane instantons. Interestingly, the required 3-form field does not arise in the underlying geometry, but rather shows up in the KK compactification in the generalized geometry obtained when the backreaction of the D-brane instanton is taken into account.

  15. Widening the Axion Window via Kinetic and Stückelberg Mixings.

    Science.gov (United States)

    Shiu, Gary; Staessens, Wieland; Ye, Fang

    2015-10-30

    We point out that kinetic and Stückelberg mixings that are generically present in the low energy effective action of axions can significantly widen the window of axion decay constants. We show that an effective super-Planckian decay constant can be obtained even when the axion kinetic matrix has only sub-Planckian entries. Our minimal model involves only two axions, a Stückelberg U(1) and a modest rank instanton generating non-Abelian group. Below the mass of the Stückelberg U(1), there is only a single axion with a nonperturbatively generated potential. In contrast to previous approaches, the enhancement of the axion decay constant is not tied to the number of degrees of freedom introduced. We also discuss how kinetic mixings can lower the decay constant to the desired axion dark matter window. String theory embeddings of this scenario and their phenomenological features are briefly discussed.

  16. Testing the ultra-light axion hypothesis using cosmic microwave background and galaxy clustering data

    Science.gov (United States)

    Grin, Daniel

    2015-08-01

    Ultra-light axions emerge from string theory and are attractive dark matter and dark energy candidates. After reviewing the motivation for ultra-light axions, I will discuss the cosmological observables in ultra-light axion cosmological scenarios, and then lay forth the methods and results of a recent search for such axions using CMB anisotropies and the clustering of galaxies, calling on Planck CMB data and the WiggleZ galaxy survey, respectively. I will then explain how isocurvature fluctuations in the CMB lead to an interesting tension between ultra-light axion dark matter and high-scale inflation, leading to interesting connections between the hunt for primordial CMB B-mode polarization and the ultra-light axion hypothesis. I will then survey the range of interesting future observational probes of the ultra-light axion dark matter hypothesis..

  17. Solitons of axion-dilaton gravity

    CERN Document Server

    Bakas, Ioannis

    1996-01-01

    We use soliton techniques of the two-dimensional reduced beta-function equations to obtain non-trivial string backgrounds from flat space. These solutions are characterized by two integers (n, m) referring to the soliton numbers of the metric and axion-dilaton sectors respectively. We show that the Nappi-Witten universe associated with the SL(2) x SU(2) / SO(1, 1) x U(1) CFT coset arises as an (1, 1) soliton in this fashion for certain values of the moduli parameters, while for other values of the soliton moduli we arrive at the SL(2)/SO(1, 1) x SO(1, 1)^2 background. Ordinary 4-dim black-holes arise as 2-dim (2, 0) solitons, while the Euclidean worm-hole background is described as a (0, 2) soliton on flat space. The soliton transformations correspond to specific elements of the string Geroch group. These could be used as starting point for exploring the role of U-dualities in string compactifications to two dimensions.

  18. Axionic D3-D7 Inflation

    CERN Document Server

    Burgess, C P; Postma, M

    2009-01-01

    We study the motion of a D3 brane moving within a Type IIB string vacuum compactified to 4D on K3 x T_2/Z_2 in the presence of D7 and O7 planes. We work within the effective 4D supergravity describing how the mobile D3 interacts with the lightest bulk moduli of the compactification, including the effects of modulus-stabilizing fluxes. We seek inflationary solutions to the resulting equations, performing our search numerically in order to avoid resorting to approximate parameterizations of the low-energy potential. We consider uplifting from D-terms and from the supersymmetry-breaking effects of anti-D3 branes. We find examples of slow-roll inflation (with anti-brane uplifting) with the mobile D3 moving along the toroidal directions, falling towards a D7-O7 stack starting from the antipodal point. The inflaton turns out to be a linear combination of the brane position and the axionic partner of the K3 volume modulus, and the similarity of the potential along the inflaton direction with that of racetrack inflat...

  19. Can Gravitational Instantons Really Constrain Axion Inflation?

    CERN Document Server

    Hebecker, Arthur; Theisen, Stefan; Witkowski, Lukas T

    2016-01-01

    Axions play a central role in inflationary model building and other cosmological applications. This is mainly due to their flat potential, which is protected by a global shift symmetry. However, quantum gravity is known to break global symmetries, the crucial effect in the present context being gravitational instantons or Giddings-Strominger wormholes. We attempt to quantify, as model-independently as possible, how large a scalar potential is induced by this general quantum gravity effect. We pay particular attention to the crucial issue which solutions can or cannot be trusted in the presence of a moduli-stabilisation and a Kaluza-Klein scale. An important conclusion is that, due to specific numerical prefactors, the effect is surprisingly small even in UV-completions with the highest possible scale offered by string theory. As we go along, we discuss in detail Euclidean wormholes, cored and extremal instantons, and how the latter arise from 5d Reissner-Nordstrom black holes. We attempt to dispel possible do...

  20. Mixed axion/neutralino cold dark matter in supersymmetric models

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Howard; Lessa, Andre; Rajagopalan, Shibi; Sreethawong, Warintorn, E-mail: baer@nhn.ou.edu, E-mail: lessa@nhn.ou.edu, E-mail: shibi@nhn.ou.edu, E-mail: wstan@nhn.ou.edu [Dept. of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)

    2011-06-01

    We consider supersymmetric (SUSY) models wherein the strong CP problem is solved by the Peccei-Quinn (PQ) mechanism with a concommitant axion/axino supermultiplet. We examine R-parity conserving models where the neutralino is the lightest SUSY particle, so that a mixture of neutralinos and axions serve as cold dark matter (a Z-tilde {sub 1} CDM). The mixed a Z-tilde {sub 1} CDM scenario can match the measured dark matter abundance for SUSY models which typically give too low a value of the usual thermal neutralino abundance, such as models with wino-like or higgsino-like dark matter. The usual thermal neutralino abundance can be greatly enhanced by the decay of thermally-produced axinos (ã) to neutralinos, followed by neutralino re-annihilation at temperatures much lower than freeze-out. In this case, the relic density is usually neutralino dominated, and goes as ∼ (f{sub a}/N)/m{sub ã}{sup 3/2}. If axino decay occurs before neutralino freeze-out, then instead the neutralino abundance can be augmented by relic axions to match the measured abundance. Entropy production from late-time axino decays can diminish the axion abundance, but ultimately not the neutralino abundance. In a Z-tilde {sub 1} CDM models, it may be possible to detect both a WIMP and an axion as dark matter relics. We also discuss possible modifications of our results due to production and decay of saxions. In the appendices, we present expressions for the Hubble expansion rate and the axion and neutralino relic densities in radiation, matter and decaying-particle dominated universes.

  1. CERN Relay Race: information for drivers

    CERN Multimedia

    2012-01-01

    The CERN relay race will take place around the Meyrin site on Thursday, 24 May starting at 12.15. If possible, please avoid driving on the site during this 20-minute period. If you do meet runners while driving your car, please STOP until they have all passed. In addition, there will be a Nordic Walking event which will finish around 12.50. This should not block the roads, but please drive carefully during this time. Thank you for your cooperation. Details on how to register your team for the relay race can be found here.

  2. The 2009 Relay Race

    CERN Multimedia

    2009-01-01

    The 2009 CERN Relay Race was as popular as ever, with a record number of 88 teams competing. var flash_video_player=get_video_player_path(); insert_player_for_external('Video/Public/Movies/2009/CERN-MOVIE-2009-048/CERN-MOVIE-2009-048-0753-kbps-480x360-25-fps-audio-64-kbps-44-kHz-stereo', 'mms://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2009/CERN-MOVIE-2009-048/CERN-MOVIE-2009-048-Multirate-200-to-753-kbps-480x360.wmv', 'false', 288, 216, 'https://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2009/CERN-MOVIE-2009-048/CERN-MOVIE-2009-048-posterframe-480x360-at-10-percent.jpg', '1178303', true, 'Video/Public/Movies/2009/CERN-MOVIE-2009-048/CERN-MOVIE-2009-048-0600-kbps-maxH-360-25-fps-audio-128-kbps-48-kHz-stereo.mp4'); Even the rain didn’t dampen the spirits, and it still managed to capture the ‘festival feeling’ with live music, beer and stalls from various CERN clubs set up outside Restaurant 1. The Powercuts on the podium after win...

  3. The Rat Race

    CERN Multimedia

    Stephen Haywood

    Dear Muriel, Being an animal, you are probably more familiar with rats than most of us. Yet it seems to me that our Community (not just ATLAS) is stuck in a huge "rat race". I am somewhat mystified as to how we have got ourselves into this and I wonder whether you or your readers could explain this - I give my own observations below. In HEP and ATLAS specifically, we are all working long hours and we are all becoming exhausted. There are people at Point 1 who are working day and night, every day of the week; there are people writing software who send emails round the clock, including weekends. It is one thing to have bursts of activity which require us to put in some longer hours, but in ATLAS, the bursts last months or years. I have been on ATLAS 14 years and it has felt like one endless rush. Why do we do this? We are all highly motivated, we love our work and want to succeed individually and collectively. We are parts of various teams, and we do not want to let the side down. We worked hard at school an...

  4. May axion clusters be sources of fast radio bursts?

    CERN Document Server

    Pshirkov, Maxim S

    2016-01-01

    Fast radio bursts can be caused by some phenomena related to 'new physics'. One of the most prominent candidates of the kind are axion miniclusters which can undergo conversion into photons in magnetospheres of neutron stars. In this short research note this scenario is investigated and important caveats are examined. First, tidal disruption of miniclusters can considerably extend the time span of conversion process, making it impossible to reach necessary $\\mathcal{O}$(ms) level. Second, existing observations at two widely separated frequencies imply that axion-related scenarios can hardly explain entirety of FRBs.

  5. Oblique corrections in the Dine-Fischler-Srednicki axion model

    Directory of Open Access Journals (Sweden)

    Katanaeva Alisa

    2016-01-01

    We discuss the Dine-Fischler-Srednicki (DFS model, which extends the two-Higgs doublet model with an additional Peccei-Quinn symmetry and leads to a physically acceptable axion. The non-linear parametrization of the DFS model is exploited in the generic case where all scalars except the lightest Higgs and the axion have masses at or beyond the TeV scale. We compute the oblique corrections and use their values from the electroweak experimental fits to put constraints on the mass spectrum of the DFS model.

  6. Towards axionic Starobinsky-like inflation in string theory

    Directory of Open Access Journals (Sweden)

    Ralph Blumenhagen

    2015-06-01

    Full Text Available It is shown that Starobinsky-like potentials can be realized in non-geometric flux compactifications of string theory, where the inflaton involves an axion whose shift symmetry can protect UV-corrections to the scalar potential. For that purpose we evaluate the backreacted, uplifted F-term axion-monodromy potential, which interpolates between a quadratic and a Starobinsky-like form. Limitations due to the requirements of having a controlled approximation of the UV theory and of realizing single-field inflation are discussed.

  7. Towards universal axion inflation and reheating in string theory

    Directory of Open Access Journals (Sweden)

    Ralph Blumenhagen

    2014-09-01

    Full Text Available The recent BICEP2 measurements of B-modes indicate a large tensor-to-scalar ratio in inflationary cosmology, which points towards trans-Planckian evolution of the inflaton. We propose possible string-theory realizations thereof. Schemes for natural and axion monodromy inflation are presented in the framework of the type IIB large volume scenario. The inflaton in both cases is given by the universal axion and its potential is generated by F-terms. Our models are shown to feature a natural mechanism for inflaton decay into predominantly Standard Model particles.

  8. Towards axionic Starobinsky-like inflation in string theory

    Energy Technology Data Exchange (ETDEWEB)

    Blumenhagen, Ralph, E-mail: blumenha@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München (Germany); Font, Anamaría, E-mail: anamaria.font@physik.lmu.de [Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München (Germany); Arnold Sommerfeld Center for Theoretical Physics, LMU, Theresienstr. 37, 80333 München (Germany); Fuchs, Michael, E-mail: mfuchs@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München (Germany); Herschmann, Daniela, E-mail: herschma@mpp.mpg.de [Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München (Germany); Plauschinn, Erik, E-mail: erik.plauschinn@pd.infn.it [Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, Via Marzolo 8, 35131 Padova (Italy); INFN, Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy)

    2015-06-30

    It is shown that Starobinsky-like potentials can be realized in non-geometric flux compactifications of string theory, where the inflaton involves an axion whose shift symmetry can protect UV-corrections to the scalar potential. For that purpose we evaluate the backreacted, uplifted F-term axion-monodromy potential, which interpolates between a quadratic and a Starobinsky-like form. Limitations due to the requirements of having a controlled approximation of the UV theory and of realizing single-field inflation are discussed.

  9. Towards universal axion inflation and reheating in string theory

    Energy Technology Data Exchange (ETDEWEB)

    Blumenhagen, Ralph [Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München (Germany); Plauschinn, Erik [Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, Via Marzolo 8, 35131 Padova (Italy); INFN, Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy)

    2014-09-07

    The recent BICEP2 measurements of B-modes indicate a large tensor-to-scalar ratio in inflationary cosmology, which points towards trans-Planckian evolution of the inflaton. We propose possible string-theory realizations thereof. Schemes for natural and axion monodromy inflation are presented in the framework of the type IIB large volume scenario. The inflaton in both cases is given by the universal axion and its potential is generated by F-terms. Our models are shown to feature a natural mechanism for inflaton decay into predominantly Standard Model particles.

  10. Axion-like particle searches with sub-THz photons

    CERN Document Server

    Capparelli, L.; Ferretti, J.; Giazotto, F.; Polosa, A.D.; Spagnolo, P.

    2016-01-01

    We propose a variation, based on very low energy and extremely intense photon sources, on the well established technique of Light-Shining-through-Wall (LSW) experiments for axion-like particle searches. With radiation sources at 30 GHz, we compute that present laboratory exclusion limits on axion-like particles might be improved by at least four orders of magnitude, for masses m_a <~ 0.01~meV. This could motivate research and development programs on dedicated single-photon sub-THz detectors.

  11. Axion-like particle searches with sub-THz photons

    Science.gov (United States)

    Capparelli, L. M.; Cavoto, G.; Ferretti, J.; Giazotto, F.; Polosa, A. D.; Spagnolo, P.

    2016-06-01

    We propose a variation, based on very low energy and extremely intense photon sources, on the well established technique of Light-Shining-through-Wall (LSW) experiments for axion-like particle searches. With radiation sources at 30 GHz, we compute that present laboratory exclusion limits on axion-like particles might be improved by at least four orders of magnitude, for masses ma ≲ 0.01 meV. This could motivate research and development programs on dedicated single-photon sub-THz detectors.

  12. Gravity and axions from a random UV QFT

    CERN Document Server

    Kiritsis, Elias

    2014-01-01

    It is postulated that the UV QFT is enormous and random. The coupling of the Standard Model to such QFT is analyzed. It is argued that massless 4d gravity and axions are general avatars of the postulate. The equivalence principle emerges naturally as well as a concrete set of sources for its breaking. The axion scale is related to the 4d Planck scale as $f=M_P/N$, where $N$ is the "number of colors" of the (almost) hidden UV CFT.

  13. Axion Search by Laser-based Experiment OSQAR

    OpenAIRE

    Sulc, Miroslav; Pugnat, Pierre; Ballou, Rafik; Deferne, Guy; Duvillaret, Lionel; Flekova, Lucie; Finger, Michael; Finger Jr, Michael; Hošek, Jan; Husek, Thomas; Jost, Rémy; Kral, Miroslav; Kunc, Štěpán; Macuchova, Karolina; Meissner, Krzysztof,

    2012-01-01

    International audience; Laser-based experimentOSQAR in CERN is aimed to the search of the axions by twomethods. The photon regeneration experiment is using two LHC dipole magnets of the length 14.3 m and magnetic field 9.5 T equipped with an optical barrier at the end of the first magnet. It looks as light shining through the wall. No excess of events above the background was detected at this arrangement. Nevertheless, this result extends the exclusion region for the axion mass. The second me...

  14. Cavity design for high-frequency axion dark matter detectors.

    Science.gov (United States)

    Stern, I; Chisholm, A A; Hoskins, J; Sikivie, P; Sullivan, N S; Tanner, D B; Carosi, G; van Bibber, K

    2015-12-01

    In an effort to extend the usefulness of microwave cavity detectors to higher axion masses, above ∼8 μeV (∼2 GHz), a numerical trade study of cavities was conducted to investigate the merit of using variable periodic post arrays and regulating vane designs for higher-frequency searches. The results show that both designs could be used to develop resonant cavities for high-mass axion searches. Multiple configurations of both methods obtained the scanning sensitivity equivalent to approximately 4 coherently coupled cavities with a single tuning rod.

  15. Gravity and axions from a random UV QFT

    Directory of Open Access Journals (Sweden)

    Kiritsis Elias

    2014-04-01

    Full Text Available It is postulated that the UV QFT is enormous and random. The coupling of the Standard Model to such QFT is analyzed. It is argued that massless 4d gravity and axions are general avatars of the postulate. The equivalence principle emerges naturally as well as a concrete set of sources for its breaking. The axion scale is related to the 4d Planck scale as f = MP/N, where N is the “number of colors" of the (almost hidden UV CFT.

  16. Buff Thermo°CoolTM Team On Top

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Andalusia 13-14 March:The Thermo°CoolTM sponsored Extreme Raid team celebrated their triumph over the fourth edition of the Adventure Raid Sierras Subbeticas.The team finished at 1st position after an exhausting race and a tough fighting against time and altitudes of above 1300 meters.Team members

  17. ATLAS participation to the 36th Annual CERN Relay Race

    CERN Multimedia

    Gagnon, P.

    On May 17, the Annual CERN relay race took place for the 36th time. This is a fun relay race where a team of six runners runs around the CERN site in Meyrin, up and down many hills, to cover the following distances: the first runner runs 1000 m, the second and third runners cover 800 m each, the fourth and fifth runners each have 500 m and finally, the sixth runner covers the last 300 m all the way to the finish line. Each year, serious and occasionnal runners who take this opportunity to make it their only running moment of the year, give it their best to run the 3.9 km loop in times ranging from a mere 10:39.9 for the best team this year to 18:14.3 for the last of the 65 teams that completed the race. Nobody was wasting time at the starting line of the CERN Annual Relay Race. ATLAS was better represented than ever with a record of eight ATLAS teams participating in this race organized by the CERN running club. The names of the ATLAS participants, as well as the team official times are given in the t...

  18. Teaming up

    DEFF Research Database (Denmark)

    Warhuus, Jan; Günzel-Jensen, Franziska; Robinson, Sarah

    Questions we care about (Objectives): When students have to work on challenging tasks, as it is often the case in entrepreneurship classrooms that leverage experiential learning, team success becomes central to the students learning. Yet, the formation of teams is often left up to the students...... or pre-arranged at random. Therefore we investigate the importance of team formation in the entrepreneurial classroom and ask: (i) What are the underlying factors that influence outcomes of teamwork in student groups? (ii) How does team formation influence student perception of learning?, and (iii) Do...... functioning entrepreneurial student teams as most teams lack personal chemistry which makes them anchor their work too much in a pre-defined project. In contrast, we find that students that can form their own teams aim for less diverse teams than what is achieved by random assignment. However, the homophily...

  19. A Model For Halo Formation With Axion Mixed Dark Matter

    CERN Document Server

    Marsh, David J E

    2013-01-01

    There are several issues to do with dwarf galaxy predictions in the standard $\\Lambda$CDM cosmology that have suscitated much recent debate about the possible modification of the nature of dark matter as providing a solution. We explore a novel solution involving ultra-light axions that can potentially resolve the missing satellites problem, the cusp-core problem, and the `too big to fail' problem. We discuss approximations to non-linear structure formation in dark matter models containing a component of ultra-light axions across four orders of magnitude in mass, $10^{-24}\\lesssim m_a \\lesssim 10^{-20}$, a range too heavy to be well constrained by linear cosmological probes such as the CMB and matter power spectrum, and too light for other astrophysical or terrestrial axion searches. We find that an axion of mass $m_a\\approx 10^{-21}\\text{eV}$ contributing $\\Omega_a/\\Omega_d \\gtrsim 0.85$ of the total dark matter can introduce a significant kpc scale core in a typical Milky Way satellite galaxy in sharp contr...

  20. Axion helioscopes update: the status of CAST & IAXO

    DEFF Research Database (Denmark)

    Dafni, T; Iguaz, F. J.; Jakobsen, Anders Clemen

    2014-01-01

    Almost 35 years since their suggestion as a good solution to the strong CP-problem, axions remainone of the few viable candidates for the Dark Matter, although still eluding detection. Mostof the methods for their detection are based on their coupling to photons, one of the most sensitiveones bei...

  1. Bertotti-Robinson type solutions to Dilaton-Axion Gravity

    CERN Document Server

    Clément, G; Clement, Gerard; Gal'tsov, Dmitri

    2001-01-01

    We present a new solution to dilaton-axion gravity which looks like a rotating Bertotti-Robinson (BR) Universe. It is supported by an homogeneous Maxwell field and a linear axion and can be obtained as a near-horizon limit of extremal rotating dilaton-axion black holes. It has the isometry $SL(2,R)\\times U(1)$ where U(1) is the remnant of the SO(3) symmetry of BR broken by rotation, while $SL(2,R)$ corresponds to the $AdS_2$ sector which no longer factors out of the full spacetime. Alternatively our solution can be obtained from the D=5 vacuum counterpart to the dyonic BR with equal electric and magnetic field strengths. The derivation amounts to smearing it in D=6 and then reducing to D=4 with dualization of one Kaluza-Klein two-form in D=5 to produce an axion. Using a similar dualization procedure, the rotating BR solution is uplifted to D=11 supergravity. We show that it breaks all supersymmetries of N=4 supergravity in D=4, and that its higher dimensional embeddings are not supersymmetric either. But, hop...

  2. A Visible QCD Axion from an Enlarged Color Group

    CERN Document Server

    Gherghetta, Tony; Shifman, Mikhail

    2016-01-01

    We consider the possibility of an enlarged QCD color group, SU(3+$N^\\prime$) spontaneously broken to SU(3)$_c\\times$SU($N^\\prime$)$\\times$U(1)$_X$ with extra vector-like quarks transforming in the fundamental representation. When the heavy quarks are integrated out below the PQ-breaking scale, they generate an axion coupling which simultaneously solves the strong CP problem for both gauge groups. However, the axion mass now receives a new nonperturbative contribution from the SU($N^\\prime$) confinement scale, which can be substantially larger than the QCD scale. This can increase the axion mass to be at or above the electroweak scale. This visible axion can then decay into gluons and photons giving rise to observable signals at Run-II of the LHC. In particular, if the mass is identified with the 750 GeV diphoton resonance then the new confinement scale $\\sim$ TeV and the PQ-breaking scale $\\sim$ 10 TeV. This predicts vector-like quarks and a PQ scalar resonance in the multi-TeV range, with the possibility tha...

  3. Axions, SN 1987A, and one pion exchange

    Science.gov (United States)

    Turner, Michael S.; Kang, Ho-Shik; Steigman, Gary

    1988-01-01

    Nucleon-nucleon, axion bremsstrahlung is the primary mechanism for axion emission from the nascent neutron star associated with SN 1987A, and the rate for this process has been calculated in the one pion exchange approximation (OPE). The axion mass limit which follows from SN 1987A, m sub a less than or approx equal to 10 to the -3 eV, is the most stringent astrophysical bound, and has received much scrutiny. It has been suggested that by using OPE to calculate the cross section for the analog process, pp yields pp + pi sup o, and comparing the result of the experimental data one can test the validity of this approximation, and further, that such a comparison indicates that OPE leads to a value for this cross section which is a factor of 30 to 40 too large. If true, this would suggest that the axion mass limit should be revised upward by a factor of approximately 6. The cross section for pp yields pp + pi sup o using OPE is carefully evaluated, and excellent agreement found (to better than a factor of 2) with the experimental data.

  4. Brane solutions of gravity-dilaton-axion systems

    NARCIS (Netherlands)

    Bergshoeff, E; Collinucci, A; Gran, U; Roest, D; Vandoren, S; Lukierski, J; Sorokin, D

    2005-01-01

    We consider general properties of brane solutions of gravity-dilaton-axion systems. We focus on the case of 7-branes and instantons. In both cases we show that besides the standard solutions there are new deformed solutions whose charges take value in any of the three conjugacy classes of SL(2, R).

  5. Oblique corrections in the Dine-Fischler-Srednicki axion model

    Science.gov (United States)

    Katanaeva, Alisa; Espriu, Domènec

    2016-11-01

    In the Minimal Standard Model (MSM) there is no degree of freedom for dark matter. There are several extensions of the MSM introducing a new particle - an invisible axion, which can be regarded as a trustworthy candidate at least for a part of the dark matter component. However, as it is extremely weakly coupled, it cannot be directly measured at the LHC. We propose to explore the electroweak sector indirectly by considering a particular model that includes the axion and derive consequences that could be experimentally tested. We discuss the Dine-Fischler-Srednicki (DFS) model, which extends the two-Higgs doublet model with an additional Peccei-Quinn symmetry and leads to a physically acceptable axion. The non-linear parametrization of the DFS model is exploited in the generic case where all scalars except the lightest Higgs and the axion have masses at or beyond the TeV scale. We compute the oblique corrections and use their values from the electroweak experimental fits to put constraints on the mass spectrum of the DFS model.

  6. Minimal Composite Dynamics versus Axion Origin of the Diphoton excess

    DEFF Research Database (Denmark)

    Molinaro, Emiliano; Sannino, Francesco; Vignaroli, Natascia

    2016-01-01

    observed. The new state can be interpreted both as an axion or as a {highly natural} composite state arising from minimal models of dynamical electroweak symmetry breaking. We further show how to disentangle the two scenarios. Beyond the possible explanation of the diphoton excess the results show...

  7. Brane Solutions of Gravity–Dilaton–Axion Systems

    NARCIS (Netherlands)

    Bergshoeff, E.; Collinucci, A.; Gran, U.; Roest, D.; Vandoren, S.; Lukierski, J.; Sorokin, D.

    2005-01-01

    We consider general properties of brane solutions of gravity-dilaton-axion systems. We focus on the case of 7-branes and instantons. In both cases we show that besides the standard solutions there are new deformed solutions whose charges take value in any of the three conjugacy classes of SL(2,R). I

  8. Seeing an invisible axion in the supersymmetric particle spectrum.

    Science.gov (United States)

    Conlon, Joseph P

    2006-12-31

    I describe how under favorable circumstances, the existence of an invisible axion could correlate with a distinctive CERN Large Hadron Collider sparticle spectrum, in particular, through a gluino approximately ln(M(P)/m(3/2)) times heavier than other gauginos.

  9. Axionic extension of the Einstein-aether theory

    CERN Document Server

    Balakin, Alexander B

    2016-01-01

    We extend the Einstein-aether theory to take into account the interaction between a pseudoscalar field, which describes the axionic dark matter, and a time-like dynamic unit vector field, which characterizes the velocity of the aether motion. The Lagrangian of the Einstein-aether-axion theory includes cross-terms based on the axion field and its gradient four-vector, on the covariant derivative of the aether velocity four-vector, and on the Riemann tensor and its convolutions. We follow the principles of the Effective Field theory, and include into the Lagrangian of interactions all possible terms up to the second order in the covariant derivative. Interpretation of new couplings is given in terms of irreducible parts of the covariant derivative of the aether velocity, namely, the acceleration four-vector, the shear and vorticity tensors, and the expansion scalar. A spatially isotropic and homogeneous cosmological model with dynamic unit vector field and axionic dark matter is considered as an application of ...

  10. Are Clinical Diagnoses of Alzheimer's Disease and Other Dementias Affected by Education and Self-Reported Race?

    Science.gov (United States)

    Teresi, Jeanne A.; Grober, Ellen; Eimicke, Joseph P.; Ehrlich, Amy R.

    2012-01-01

    A randomized controlled trial examined whether the diagnostic process for Alzheimer's disease and other dementias may be influenced by knowledge of the patient's education and/or self-reported race. Four conditions were implemented: diagnostic team knows (a) race and education, (b) education only, (c) race only, or (d) neither. Diagnosis and…

  11. Affectivity and race

    DEFF Research Database (Denmark)

    of the Nordic countries, Affectivity and Race draws on a variety of sources, including television programmes, news media, fictional literature, interviews, ethnographic observations, teaching curricula and policy documents, to explore the ways in which ideas about affectivity and emotion afford new insights...... into the experience of racial difference and the unfolding of political discourses on race in various social spheres. Organised around the themes of the politicisation of race through affect, the way that race produces affect and the affective experience of race, this interdisciplinary collection sheds light...... on the role of feelings in the formation of subjectivities, how race and whiteness are affectively circulated in public life and the ways in which emotions contribute to regimes of inclusion and exclusion. As such it will appeal to scholars across the social sciences, with interests in sociology, anthropology...

  12. The success of the 45th CERN Relay Race

    CERN Multimedia

    CERN Bulletin

    2015-01-01

    On Thursday, 21 May, 783 people (9 Nordic walkers and 129 teams of 6 runners each) took part in the 45th CERN Relay Race.   The teams were divided into eight different categories: three CERN categories (Seniors, Dames, Mixte) – in which the six runners in the team must belong to the same professional unit – and four “open” categories (Open, Veterans Open, Dames Open, Mixte Open) - in which the six runners in the team do not necessarily belong to the same professional unit and can include people from outside CERN. Each team covered 3,600 metres around the Meyrin site, with the race's fastest runners covering this distance in only 11 minutes and 5 seconds! (See all the results here. For more photos from the event, see here, here and here.)  

  13. CERN Relay Race: a great success!

    CERN Multimedia

    Staff Association

    2016-01-01

    On Thursday May 19, the traditional relay race was held at CERN, organised jointly by the Running Club and the CERN Staff Association. In spite of the less than optimal weather, the 127 registered teams were not discouraged. Warmed by their efforts on the roads of CERN, the participants were able to withstand the chilly May weather. The start signal for the race was given by our Director General, demonstrating the interest in this event at the highest level of the Organization. Thank you for this much appreciated commitment! Can we hope for next year to see a team from the Directorate in the race? The many spectators who had come to cheer on the runners could also visit the stalls staffed by a few clubs and some of Interfon’s commercial partners. Refreshment and food stands contributed to the friendly atmosphere. The organisation of such an event requires however a substantial investment in order to cover all aspects of logistics, from preparation before the race, to the actual establishment ...

  14. Non-gaussianity in axion N-flation models Quadratic and $\\lambda\\phi^4$ plus axion potentials

    CERN Document Server

    Kamarpour, Mehran

    2012-01-01

    In this paper we investigate large non-gaussianity in axion N-flation models, taking account while dynamically a large number of axions begin away from the hilltop region(come down from the hill) and so serve only to be the source of the Hubble rate. Therefore the single field stays closest to the hilltop sources the non-Gaussianity. In this case most of axions can be replaced by a single effective field with a quadratic potential. So our potential will contain two fields. The full cosine is responsible for the axion closest to hilltop and quadratic term which is a source for Hubble rate [4]. We obtain power spectrum, spectral index and non-gaussianity parameter, then we impose conditions from WMAP for power spectrum and spectral index and see how large on non-gaussianity parameter it is possible to achieve with such conditions. Finally we swap quadratic term to {\\lambda}{\\phi}^4 and see whether this makes it harder or easier to achieve large non-gaussianity.We find large non-gaussianity is achievable by impo...

  15. Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

    Science.gov (United States)

    Arik, M; Aune, S; Barth, K; Belov, A; Borghi, S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Da Riva, E; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galán, J; García, J A; Gardikiotis, A; Garza, J G; Gazis, E N; Geralis, T; Georgiopoulou, E; Giomataris, I; Gninenko, S; Gómez, H; Gómez Marzoa, M; Gruber, E; Guthörl, T; Hartmann, R; Hauf, S; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovčić, K; Karuza, M; Königsmann, K; Kotthaus, R; Krčmar, M; Kuster, M; Lakić, B; Lang, P M; Laurent, J M; Liolios, A; Ljubičić, A; Luzón, G; Neff, S; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Riege, H; Rodríguez, A; Rosu, M; Ruz, J; Savvidis, I; Shilon, I; Silva, P S; Solanki, S K; Stewart, L; Tomás, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J; Vogel, J K; Yildiz, S C; Zioutas, K

    2014-03-07

    The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ ≲ 3.3 × 10(-10)  GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.

  16. Axion electrodynamics and dark matter fingerprints in the terrestrial magnetic and electric fields

    CERN Document Server

    Balakin, A B

    2012-01-01

    We consider mathematical aspects of the axion electrodynamics in application to the problem of evolution of geomagnetic and terrestrial electric fields, which are coupled by relic axions born in the early Universe and (hypothetically) forming now the cold dark matter. We find axionic analogs of the Debye potentials, well-known in the standard Faraday - Maxwell electrodynamics, and discuss exact solutions to the equations of the axion electrodynamics describing the state of axionically coupled electric and magnetic fields in a spherical resonator Earth-Ionosphere. We focus on the properties of the specific electric and magnetic oscillations, which appeared as a result of the axion-photon coupling in the dark matter environment. We indicate such electric and magnetic field configurations as longitudinal electro-magnetic clusters.

  17. Constraining axion coupling constants from measuring the Casimir interaction between polarized test bodies

    CERN Document Server

    Bezerra, V B; Mostepanenko, V M; Romero, C

    2016-01-01

    We propose an experiment for measuring the effective Casimir pressure between two parallel SiC plates with aligned nuclear spins. The prospective constraints on an axion-neutron coupling constant for both hadronic and GUT axions are calculated using the process of one-axion exchange. For this purpose, a general expression for the additional pressure arising between two polarized plates due to the exchange of one axion between their constituent fermions is derived. We demonstrate that only the polarization component perpendicular to the plates contribute to the pressure. The obtained pressure can be both repulsive and attractive depending on whether the polarizations of both plates are unidirectional or directed in opposite directions. It is shown that although the constraints on an axion-electron coupling obtained in the case of magnetized plates are not competitive, the constraints on an axion-neutron coupling found for plates with polarized nuclear spins are of the same order of magnitude of those obtained ...

  18. QCD Axion as a Bridge Between String Theory and Flavor Physics

    CERN Document Server

    Ahn, Y H

    2016-01-01

    We construct a string-inspired model, motivated by the flavored Peccei-Quinn (PQ) axions, as a useful bridge between flavor physics and string theory. The key feature is two anomalous gauged $U(1)$ symmetries, responsible for both the fermion mass hierarchy problem of the standard model and the strong CP problem, that combine string theory with flavor physics and severely constrain the form of the F- and D-term contributions to the potential. In the context of supersymmetric moduli stabilization we stabilize the size moduli with positive masses while leaving two axions massless and one axion massive. We demonstrate that, while the massive gauge bosons eat the two axionic degrees of freedom, two axionic directions survive to low energies as the flavored PQ axions.

  19. Mississippi State Axion Search: A Light Shining though a Wall ALP Search

    CERN Document Server

    Mohanmurthy, Prajwal; Formaggio, Joseph; Fowler, Nicholas; Gaerlan, Mikhail; Jiang, Yipeng; Madsen, John; Oblath, Noah; Powers, Adam; Ray, Amy; Riehle, Robertson

    2015-01-01

    The elegant solutions to the strong CP problem predict the existence of a particle called axion. Thus, the search for axion like particles (ALP) has been an ongoing endeavor. The possibility that these axion like particles couple to photons in presence of magnetic field gives rise to a technique of detecting these particles known as light shining through a wall (LSW). Mississippi State Axion Search (MASS) is an experiment employing the LSW technique in search for axion like particles. The apparatus consists of two radio frequency (RF) cavities, both under the influence of strong magnetic field and separated by a lead wall. While one of the cavities houses a strong RF generator, the other cavity houses the detector systems. The MASS apparatus looks for excesses in RF photons that tunnel through the wall as a signature of candidate axion-like particles. The concept behind the experiment as well as the projected sensitivities are presented here.

  20. MADMAX: A new Dark Matter Axion Search using a Dielectric Haloscope

    CERN Document Server

    Majorovits, Béla

    2016-01-01

    The axion is an intriguing dark matter candidate emerging from the Peccei-Quinn solution to the strong CP problem. Current experimental searches for axion dark matter focus on the axion mass range below 40 $\\mu$eV. However, if the Peccei-Quinn symmetry is restored after inflation the observed dark matter density points to an axion mass around 100 $\\mu$eV. A new project based on axion-photon conversion at the transition between different dielectric media is presented. By using $\\sim 80$ dielectric discs, the emitted power could be enhanced by a factor of $\\sim 10^5$ over that from a single mirror (flat dish antenna). Within a 10 T magnetic field, this could be enough to detect $\\sim 100 \\mu$eV axions with HEMT linear amplifiers. The design for an experiment is proposed. Results from noise, transmissivity and reflectivity measurements obtained in a prototype setup are presented. The expected sensitivity is shown.

  1. Evolving Pacing Strategies for Team Pursuit Track Cycling

    CERN Document Server

    Wagner, Markus; Jordan, Diora; Kroeger, Trent; Neumann, Frank

    2011-01-01

    Team pursuit track cycling is a bicycle racing sport held on velodromes and is part of the Summer Olympics. It involves the use of strategies to minimize the overall time that a team of cyclists needs to complete a race. We present an optimisation framework for team pursuit track cycling and show how to evolve strategies using metaheuristics for this interesting real-world problem. Our experimental results show that these heuristics lead to significantly better strategies than state-of-art strategies that are currently used by teams of cyclists.

  2. CERN runners on the podium for the Escalade race

    CERN Multimedia

    Caroline Duc

    2012-01-01

    For the last race of the season, CERN runners distinguished themselves by notching up third place in the inter-entreprises category of the Escalade, Geneva’s famous running race across the city.   Some of the runners from the CERN team. On Friday 30 November and Saturday 1 December, 35 runners from CERN braved the chilly Geneva weather to take part in the 35th Escalade race. With 81 teams competing in the race, the group representing the Laboratory took third place in the inter-entreprises category, behind the Hôpitaux Universitaires de Genève and the Panards Migros teams.   CERN’s Helenka Przysiezniak, Steffen Doebert and Camille Ruiz Llamas also distinguished themselves individually by finishing eighth, sixth and fourth in their respective categories and Patrick Villeton achieved a very good ranking in the DUC race on Friday evening and in the classic race on Saturday. Congratulations to everyone who participated and see you next ...

  3. F-term stabilization of odd axions in LARGE volume scenario

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Xin, E-mail: gaoxin@mppmu.mpg.de [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, 80805 München (Germany); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190 (China); Shukla, Pramod, E-mail: shukla@mppmu.mpg.de [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, 80805 München (Germany)

    2014-01-15

    In the context of the LARGE volume scenario, stabilization of axionic moduli is revisited. This includes both even and odd axions with their scalar potential being generated by F-term contributions via various tree-level and non-perturbative effects like fluxed E3-brane instantons and fluxed poly-instantons. In all the cases, we estimate the decay constants and masses of the axions involved.

  4. Cryogenic cavity detector for a large-scale cold dark-matter axion search

    CERN Document Server

    Peng, H; Daw, E; Golubev, N A; Hagmann, C A; Kinion, D; Laveigne, J; Moltz, D M; Nezrick, F A; Powell, J; Rosenberg, L J; Sikivie, P; Stoeffl, W; Sullivan, N S; Tanner, D B; Turner, M S; Bibber, K V

    2000-01-01

    An axion detector consisting of a tunable high-Q cavity, a superconducting magnet, and a superheterodyne receiver with an ultra-low noise pre-amplifier has been built to search for galactic halo axions in the mass range of 1.3-13 mu eV. The detector instrumentation, search process, and data analysis are described. For the first time, this class of detector has reached sufficient sensitivity to detect halo axions with high confidence.

  5. Axion Inflation with an SU(2) Gauge Field: Detectable Chiral Gravity Waves

    CERN Document Server

    Maleknejad, Azadeh

    2016-01-01

    We study a single field axion inflation model in the presence of an SU(2) gauge field with a small vev. In order to make the analysis as model-independent as possible, we consider an arbitrary potential for the axion that is able to support the slow-roll inflation. The gauge field is coupled to the axion with a Chern-Simons interaction $\\frac{\\lambda}{f}F_{\\mu\

  6. The GammeV suite of experimental searches for axion-like particles

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H.; /Fermilab; Upadhye, Amol; /KICP, Chicago /Chicago U., EFI

    2009-08-01

    We report on the design and results of the GammeV search for axion-like particles and for chameleon particles. We also discuss plans for an improved experiment to search for chameleon particles, one which is sensitive to both cosmological and power-law chameleon models. Plans for an improved axion-like particle search using coupled resonant cavities are also presented. This experiment will be more sensitive to axion-like particles than stellar astrophysical models or current helioscope experiments.

  7. CERN Relay Race: No records broken in a bumper year

    CERN Multimedia

    2007-01-01

    Tribute is paid to David Dallman, 20 times the organiser of the CERN Relay Race, who is now retiring.Solve the following mathematical problem for athletes: take the first and third-placed teams in the 2006 CERN Relay Race, randomly mix the runners to form two new teams, and what is the result? Answer: first place and fifth place. In short, the team which has reigned supreme in first place since 2001, the "Shabbys", decided to spice up the race this year by merging with their arch rivals, the "Latinos Volantes", themselves no strangers to the podium. And at the winning line, it was the hybrid formation, "Shabbys Volantes", which took the honours (no surprises there!). Sadly, they were unable to beat the Shabbys’ previous record nor get anywhere near the all-time race record of 10 minutes and 13 seconds for the 3.9-km course, held for a quarter of a century by the "UA1 Strollers". One of the members of that legendary team and race organiser 20 times, David Dallman, mar...

  8. The Challenge of Realizing F-term Axion Monodromy Inflation in String Theory

    CERN Document Server

    Blumenhagen, Ralph; Plauschinn, Erik

    2014-01-01

    A systematic analysis of possibilities for realizing single-field F-term axion monodromy inflation via the flux-induced superpotential in type IIB string theory is performed. In this well-defined setting, the conditions arising from moduli stabilization are taken into account. Our analysis leads to a no-go theorem, if the inflaton involves the universal axion. We furthermore construct the first explicit example of F-term axion monodromy inflation, in which a single axion-like field is hierarchically lighter than all remaining complex-structure moduli.

  9. 5th Patras workshop on axions, WIMPs and WISPs (PATRAS 2009). Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Jaeckel, Joerg; Lindner, Axel; Redondo, Javier (eds.)

    2010-06-15

    The following topics were dealt with: Direct searches for dark matter, indirect searches for WIMPS, photon generation and laser polarization experiments, direct axion signals, theoretic WISP developments. (HSI)

  10. The International Axion Observatory IAXO. Letter of Intent to the CERN SPS committee

    CERN Document Server

    Irastorza, Igor G; Avignone, F. T.; Betz, M.; Brax, P.; Brun, P.; Cantatore, G.; Carmona, J. M.; Carosi, G. P.; Caspers, F.; Caspi, S.; Cetin, S. A.; Chelouche, D.; Christensen, F. E.; Dael, A.; Dafni, T.; Davenport, M.; Derbin, A.V.; Desch, K.; Diago, A.; Dobrich, B. D.; Dratchnev, I.; Dudarev, A.; Eleftheriadis, C.; Fanourakis, G.; Ferrer-Ribas, E.; Galan, J.; Garcia, J. A.; Garza, J. G.; Geralis, T.; Gimeno, B.; Giomataris, I.; Gninenko, S.; Gomez, H.; Gonzalez-Diaz, D.; Guendelman, E.; Hailey, C. J.; Hiramatsu, T.; Hoffmann, D. H. H.; Horns, D.; Iguaz, F. J.; Isern, J.; Imai, K.; Jakobsen, A. C.; Jaeckel, J.; Jakovcic, K.; Kaminski, J.; Kawasaki, M.; Karuza, M.; Krcmar, M.; Kousouris, K.; Krieger, C.; Lakic, B.; Limousin, O.; Lindner, A.; Liolios, A.; Luzon, G.; Matsuki, S.; Muratova, V. N.; Nones, C.; Ortega, I.; Papaevangelou, T.; Pivovaroff, M. J.; Raffelt, G.; Redondo, J.; Ringwald, A.; Russenschuck, S.; Ruz, J.; Saikawa, K.; Savvidis, I.; Sekiguchi, T.; Semertzidis, Y. K.; Shilon, I.; Sikivie, P.; Silva, H.; Kate, H. ten; Tomas, A.; Troitsky, S.; Vafeiadis, T.; van Bibber, K.; Vedrine, P.; Villar, J. A.; Vogel, J. K.; Walckiers, L.; Weltman, A.; Wester, W.; Yildiz, S. C.; Zioutas, K.; CERN. Geneva. SPS and PS Experiments Committee; SPSC

    2013-01-01

    This Letter of Intent describes IAXO, the International Axion Observatory, a proposed 4th generation axion helioscope. As its primary physics goal, IAXO will look for axions or axion-like particles (ALPs) originating in the Sun via the Primakoff conversion of the solar plasma photons. In terms of signal to background ratio, IAXO will be about 4-5 orders of magnitude more sensitive than CAST, which means that this instrument will reach sensitivity to axion-photon couplings down to a few $\\times 10^{-12}$ GeV$^{-1}$. IAXO has the potential for the discovery of axions and other ALPs, since it will deeply enter into unexplored parameter space. At the very least it will firmly exclude a large region of this space of high cosmological and astrophysical relevance. In particular it will probe a large fraction of the high mass part (1 meV to 1 eV) of the QCD axion allowed window. Additional physics cases for IAXO include the possibility of detecting solar axions produced by mechanisms mediated by the axion-electron co...

  11. Axion-photon conversion in space and in low symmetrical dielectric crystals

    Science.gov (United States)

    Gorelik, V. S.

    2016-07-01

    The opportunities of axions detection as the result of axion-photon conversion processes in the space and in low symmetrical dielectric crystals are discussed. In accordance with the modern theory predictions, axions are pseudoscalar vacuum particles having very small (0.001-1.0 meV) rest energy. The possibility of axions conversion into photons and vice-versa processes in vacuum at the presence of outer magnetic field has been analyzed before. Pseudoscalar (axion type) modes are existing in some types of crystals. Polar pseudoscalar lattice and exciton modes in low symmetrical crystals are strongly interacted with axions. In this work, optical excitation of axion-type modes in low symmetrical crystals is proposed for observation of axion - photon conversion processes. Instead of outer magnetic field, the crystalline field of such crystals may be used. The experimental schemes for axion-photon conversion processes observation with recording the secondary emission of luminescence, infrared or Stimulated Raman Scattering in some dielectric crystals are discussed.

  12. Axion decay constants at special points in type II string theory

    Science.gov (United States)

    Honda, Masaki; Oikawa, Akane; Otsuka, Hajime

    2017-01-01

    We propose the mechanism to disentangle the decay constant of closed string axion from the string scale in the framework of type II string theory on Calabi-Yau manifold. We find that the quantum and geometrical corrections in the prepotential that arise at some special points in the moduli space widen the window of axion decay constant. In particular, around the small complex structure points, the axion decay constant becomes significantly lower than the string scale. We also discuss the moduli stabilization leading to the phenomenologically attractive low-scale axion decay constant.

  13. Axion decay constants at special points in type II string theory

    CERN Document Server

    Honda, Masaki; Otsuka, Hajime

    2016-01-01

    We propose the mechanism to disentangle the decay constant of closed string axion from the string scale in the framework of type II string theory on Calabi-Yau manifold. We find that the quantum and geometrical corrections in the prepotential that arise at some special points in the moduli space widen the window of axion decay constant. In particular, around the small complex structure points, the axion decay constant becomes significantly lower than the string scale. We also discuss the moduli stabilization leading to the phenomenologically attractive low-scale axion decay constant.

  14. Experimental Search for Solar Axions via Coherent Primakoff Conversion in a Germanium Spectrometer

    CERN Document Server

    Avignone, F T; Brodzinski, R; Collar, J I; Creswick, R J; Di Gregorio, D E; Farach, H A; Gattone, A O; Guérard, C K; Hasenbalg, F; Huck, H; Miley, H S; Morales, A; Morales, J; Nussinov, S; De Solorzano, A O; Reeves, J H; Villar, J; Zioutas, Konstantin

    1998-01-01

    Results are reported of an experimental search for the unique, rapidly varying temporal pattern of solar axions coherently converting into photons via the Primakoff effect in a single crystal germanium detector. This conversion is predicted when axions are incident at a Bragg angle with a crystalline plane. The analysis of approximately 1.94 kg.yr of data from the 1 kg DEMOS detector in Sierra Grande, Argentina, yields a new laboratory bound on axion-photon coupling of $g_{a\\gamma \\gamma} < 2.7\\cdot 10^{-9}$ GeV$^{-1}$, independent of axion mass up to ~ 1 keV.

  15. A comparison of ultra-endurance cyclists in a qualifying ultra-cycling race for Paris-Brest-Paris and Race Across America-Swiss cycling marathon.

    Science.gov (United States)

    Knechtle, Beat; Wirth, Andrea; Knechtle, Patrizia; Rüst, Christoph Alexander; Rosemann, Thomas

    2012-02-01

    Ultra-endurance events test the adaptation of human physiology to extreme physical and mental demands, high levels of training, motivation, and physical conditioning among participants. To understand basic differences among participants according to the severity of the race, participants in qualifying events for two ultra-endurance cycling races, differing in length and intensity, were compared on measures of anthropometry, training, and support. One race was four times longer, required supporting teams, and racers typically had little sleep, which should lead to the qualifiers being substantially more highly trained than those from the shorter race. The qualifiers in the longer race had greater intensity in training while the qualifiers in the shorter race relied more on training volume. Different strategies and types of training reflected the different demands of the races. Future studies should evaluate personality and motivational differences in ultra-endurance events and between these athletes and athletes in other sports.

  16. Testing the race inequality

    DEFF Research Database (Denmark)

    Gondan, Matthias; Heckel, A.

    2008-01-01

    In speeded response tasks with redundant signals, parallel processing of the redundant signals is generally tested using the so-called race inequality. The race inequality states that the distribution of fast responses for a redundant stimulus never exceeds the summed distributions of fast...

  17. Prejudice and Race Relations.

    Science.gov (United States)

    Mack, Raymond W., Ed.

    Contents of this book comprises: Introduction--A decade of change; (1) Race and its consequences: Beliefs and acts; (2) Race relations in different societies: A comparative perspective; (3) Implementing discrimination: the institutional impact of prejudice; (4) Leaders in change: A set of profiles; and (5) Options facing Americans: Pathos to…

  18. The axion dark matter search at CAPP: a comprehensive approach

    Science.gov (United States)

    Semertzidis, Yannis

    2017-01-01

    Axions are the result of a dynamic field, similar to Higgs field, invented to solve the so-called Strong CP-problem, i.e., why the electric dipole moment (EDM) of the neutron and proton has not been observed so far even though the theory of QCD predicts values by about ten order of magnitude larger than current experimental limits. Axions as dark matter can be thought of as an oscillatory field interacting extremely weakly with normal matter. The oscillation frequency is unknown, it can be anywhere between f = 200MHz to 200GHz and it's expected to be at a very narrow line, about d f/ f = 10-6. A strong magnetic field can be used to convert part of that field into a very weak electric field oscillating at the same frequency and phase as the axion field. In the coming years we plan to develop our experimental sensitivity to either observe or refute the axions as a viable dark matter candidate in a wide axion mass range. That approach includes the development of ultra strong magnets, high quality resonators in the presence of strong B-fields, new resonator geometries, low noise cryo-amplifiers and new techniques of detecting axions. Another related subject, through the strong CP-problem, is the search for the EDM of the proton, improving the present sensitivity on hadronic EDMs by more than three orders of magnitude to better than 10-29 e-cm. Usually the study of EDM involves the application of strong electric fields and originally neutral systems were thought to be easier to work with. Recently it became clear that charged particles in all-electric storage rings can be used for sensitive EDM searches by using techniques similar to the muon g-2 experiment. The high sensitivity study of the proton EDM is possible due to the high intensity polarized proton beams readily available today, making possible to reach 103 TeV in New Physics scale.

  19. Chaotic inflation with kinetic alignment of axion fields

    Science.gov (United States)

    Bachlechner, Thomas C.; Dias, Mafalda; Frazer, Jonathan; McAllister, Liam

    2015-01-01

    N-flation is a radiatively stable scenario for chaotic inflation in which the displacements of N ≫1 axions with decay constants f1≤…≤fNaxion kinetic term generically leads to the phenomenon of kinetic alignment, allowing for effective displacements as large as √{N }fN≥fPy, even if f1,…,fN -1 are arbitrarily small. At the level of kinematics, the necessary alignment occurs with very high probability, because of eigenvector delocalization. We present conditions under which inflation can take place along an aligned direction. Our construction sharply reduces the challenge of realizing N-flation in string theory.

  20. The topological susceptibility in finite temperature QCD and axion cosmology

    CERN Document Server

    Petreczky, Peter; Sharma, Sayantan

    2016-01-01

    We study the topological susceptibility in 2+1 flavor QCD above the chiral crossover transition temperature using Highly Improved Staggered Quark action and several lattice spacings, corresponding to temporal extent of the lattice, $N_\\tau=6,8,10$ and $12$. We observe very distinct temperature dependences of the topological susceptibility in the ranges above and below $250$ MeV. While for temperatures above $250$ MeV, the dependence is found to be consistent with dilute instanton gas approximation, at lower temperatures the fall-off of topological susceptibility is milder. We discuss the consequence of our results for cosmology wherein we estimate the bounds on the axion decay constant and the oscillation temperature if indeed the QCD axion is a possible dark matter candidate.

  1. Subleading Effects and the Field Range in Axion Inflation

    CERN Document Server

    Parameswaran, Susha; Zavala, Ivonne

    2016-01-01

    An attractive candidate for the inflaton is an axion slowly rolling down a flat potential protected by a perturbative shift symmetry. Realisations of this idea within large field, natural and chaotic inflation have been disfavoured by observations and are difficult to embed in string theory. We show that subleading, but significant non-perturbative corrections can superimpose sharp cliffs and gentle plateaus into the potential, whose overall effect is to enhance the number of e-folds of inflation. Sufficient e-folds are therefore achieved for smaller field ranges compared to the potential without such corrections. Thus, both single-field chaotic and natural inflation in UV complete theories like string theory, can be restored into the favour of current observations, with distinctive signatures. Tensor modes result un-observably small, but there is a large negative running of the spectral index. Remarkably, natural inflation can be achieved with a single field whose axion decay constant is sub-Planckian.

  2. Subleading effects and the field range in axion inflation

    Science.gov (United States)

    Parameswaran, Susha; Tasinato, Gianmassimo; Zavala, Ivonne

    2016-04-01

    An attractive candidate for the inflaton is an axion slowly rolling down a flat potential protected by a perturbative shift symmetry. Realisations of this idea within large field, natural and monomial inflation have been disfavoured by observations and are difficult to embed in string theory. We show that subleading, but significant non-perturbative corrections can superimpose sharp cliffs and gentle plateaus into the potential, whose overall effect is to enhance the number of e-folds of inflation. Sufficient e-folds are therefore achieved for smaller field ranges compared to the potential without such corrections. Thus, both single-field natural and monomial inflation in UV complete theories like string theory, can be restored into the favour of current observations, with distinctive signatures. Tensor modes result un-observably small, but there is a large negative running of the spectral index. Remarkably, natural inflation can be achieved with a single field whose axion decay constant is sub-Planckian.

  3. Axion cosmology, lattice QCD and the dilute instanton gas

    Energy Technology Data Exchange (ETDEWEB)

    Borsanyi, S. [Wuppertal Univ. (Germany). Dept. of Physics; Dierigl, M.; Ringwald, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fodor, Z. [Wuppertal Univ. (Germany). Dept. of Physics; Forschungszentrum Juelich (Germany). Inst. for Advanced Simulation (IAS), Juelich Supercomputing Centre (JSC); Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics; Katz, S.D. [Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics; MTA-ELTE Lenduelet Lattice Gauge Theory Research Group, Budapest (Hungary); Mages, S.W. [Rgensburg Univ. (Germany); Forschungszentrum Juelich (Germany). Inst. for Advanced Simulation (IAS), Juelich Supercomputing Centre (JSC); Nogradi, D. [Lorand Eoetvoes Univ., Budapest (Hungary). Inst. for Theoretical Physics; MTA-ELTE Lenduelet Lattice Gauge Theory Research Group, Budapest (Hungary); Califonia Univ., Santa Barbara, CA (United States). Kavli Inst. for Theoretical Physics; Redondo, J. [Zaragoza Univ. (Spain). Dept. de Fisica Teorica; Max-Planck-Institut fuer Physik, Muenchen (Germany); Szabo, K.K. [Wuppertal Univ. (Germany). Dept. of Physics; Forschungszentrum Juelich (Germany). Inst. for Advanced Simulation (IAS), Juelich Supercomputing Centre (JSC)

    2015-08-15

    Axions are one of the most attractive dark matter candidates. The evolution of their number density in the early universe can be determined by calculating the topological susceptibility χ(T) of QCD as a function of the temperature. Lattice QCD provides an ab initio technique to carry out such a calculation. A full result needs two ingredients: physical quark masses and a controlled continuum extrapolation from non-vanishing to zero lattice spacings. We determine χ(T) in the quenched framework (infinitely large quark masses) and extrapolate its values to the continuum limit. The results are compared with the prediction of the dilute instanton gas approximation (DIGA). A nice agreement is found for the temperature dependence, whereas the overall normalization of the DIGA result still differs from the non-perturbative continuum extrapolated lattice results by a factor of order ten. We discuss the consequences of our findings for the prediction of the amount of axion dark matter.

  4. Literature in Focus: "Axions: Theory, Cosmology, and Experimental Searches"

    CERN Multimedia

    2009-01-01

    Axions are peculiar hypothetical particles that could both solve the CP problem of quantum chromodynamics and at the same time account for the dark matter of the universe. Based on a series of lectures by world experts in this field held at CERN, this volume provides a pedagogical introduction to the theory, cosmology and astrophysics of these fascinating particles and gives an up-to-date account of the status and prospect of ongoing and planned experimental searches. Learners and practitioners of astroparticle physics will find in this book both a concise introduction and a current reference work to a showcase topic that connects the "inner space" of the elementary particle world with the "outer space" of the universe at large. The book will be presented by Markus Kuster. "Axions: Theory, Cosmology, and Experimental Searches", edited by M. Kuster (Technische Universität Darmstadt), G. Raffelt (Max-Planck-Institu...

  5. Axionic dark matter signatures in various halo models

    Science.gov (United States)

    Vergados, J. D.; Semertzidis, Y. K.

    2017-02-01

    In the present work we study possible signatures in the Axion Dark Matter searches. We focus on the dependence of the expected width in resonant cavities for various popular halo models, leading to standard velocity distributions, e.g. Maxwell-Boltzmann, as well as phase-mixed and non-virialized axionic dark matter (flows, caustic rings). We study, in particular, the time dependence of the resonance width (modulation) arising from such models. We find that the difference between the maximum (in June) and the minimum (in December) can vary by about 10% in the case of standard halos. In the case of mixed phase halos the variation is a bit bigger and for caustic rings the maximum is expected to occur a bit later. Experimentally such a modulation is observable with present technology.

  6. An invisible axion model with controlled FCNCs at tree level

    Energy Technology Data Exchange (ETDEWEB)

    Celis, Alejandro, E-mail: alejandro.celis@ific.uv.es [Departament de Física Teòrica and IFIC, Universitat de València-CSIC, E-46100, Burjassot (Spain); Fuentes-Martín, Javier, E-mail: javier.fuentes@ific.uv.es [Departament de Física Teòrica and IFIC, Universitat de València-CSIC, E-46100, Burjassot (Spain); Department of Physics, National Tsing Hua University, Hsinchu 300, Taiwan (China); Serôdio, Hugo, E-mail: hserodio@kaist.ac.kr [Departament de Física Teòrica and IFIC, Universitat de València-CSIC, E-46100, Burjassot (Spain); Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2015-02-04

    We derive the necessary conditions to build a class of invisible axion models with Flavor Changing Neutral Currents at tree-level controlled by the fermion mixing matrices and present an explicit model implementation. A horizontal Peccei–Quinn symmetry provides a solution to the strong CP problem via the Peccei–Quinn mechanism and predicts a cold dark mater candidate, the invisible axion or familon. The smallness of active neutrino masses can be explained via a type I seesaw mechanism, providing a dynamical origin for the heavy seesaw scale. The possibility to avoid the domain wall problem stands as one of the most interesting features of the type of models considered. Experimental limits relying on the axion–photon coupling, astrophysical considerations and familon searches in rare kaon and muon decays are discussed.

  7. Axion search by laser-based experiment OSQAR

    Science.gov (United States)

    Sulc, M.; Pugnat, P.; Ballou, R.; Deferne, G.; Duvillaret, L.; Flekova, L.; Finger, M.; Finger, M.; Hosek, J.; Husek, T.; Jost, R.; Kral, M.; Kunc, S.; Macuchova, K.; Meissner, K. A.; Morville, J.; Romanini, D.; Schott, M.; Siemko, A.; Slunecka, M.; Vitrant, G.; Zicha, J.

    2013-08-01

    Laser-based experiment OSQAR in CERN is aimed to the search of the axions by two methods. The photon regeneration experiment is using two LHC dipole magnets of the length 14.3 m and magnetic field 9.5 T equipped with an optical barrier at the end of the first magnet. It looks as light shining through the wall. No excess of events above the background was detected at this arrangement. Nevertheless, this result extends the exclusion region for the axion mass. The second method wants to measure the ultra-fine vacuum magnetic birefringence for the first time. An optical scheme with electro-optical modulator has been proposed, validated and subsequently improved. Cotton-Mouton constant for air was determined in this experiment setup.

  8. Axion search by laser-based experiment OSQAR

    Energy Technology Data Exchange (ETDEWEB)

    Sulc, M., E-mail: miroslav.sulc@tul.cz [Technical University of Liberec (Czech Republic); Pugnat, P. [LNCMI-G, CNRS-UJF-UPS-INSA, BP 166, 38042 Grenoble Cedex-9 (France); Ballou, R. [Institut Néel, CNRS and Université Joseph Fourier, BP 166, 38042 Grenoble Cedex-9 (France); Deferne, G. [CERN, CH-1211 Geneva-23 (Switzerland); Duvillaret, L. [IMEP-LAHC, UMR CNRS 5130, Minatec-INPG, 3 parvis Louis Néel, BP 257, 38016 Grenoble Cedex-1 (France); Flekova, L. [Czech Technical University, Faculty of Mechanical Engineering, Prague (Czech Republic); Finger, M.; Finger, M. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Hosek, J. [Czech Technical University, Faculty of Mechanical Engineering, Prague (Czech Republic); Husek, T. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Jost, R. [LSP, UMR CNRS 5588, Université Joseph Fourier, BP 87, 38402 Saint-Martin d' Hères (France); Kral, M. [Czech Technical University, Faculty of Mechanical Engineering, Prague (Czech Republic); Kunc, S. [Technical University of Liberec (Czech Republic); Macuchova, K. [Czech Technical University, Faculty of Mechanical Engineering, Prague (Czech Republic); Meissner, K.A. [Institute of Theoretical Physics, University of Warsaw (Poland); Morville, J. [LASIM, UMR CNRS 5579, Université Claude Bernard Lyon-1, 69622 Villeurbanne (France); Romanini, D. [LSP, UMR CNRS 5588, Université Joseph Fourier, BP 87, 38402 Saint-Martin d' Hères (France); Schott, M.; Siemko, A. [CERN, CH-1211 Geneva-23 (Switzerland); Slunecka, M. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); and others

    2013-08-01

    Laser-based experiment OSQAR in CERN is aimed to the search of the axions by two methods. The photon regeneration experiment is using two LHC dipole magnets of the length 14.3 m and magnetic field 9.5 T equipped with an optical barrier at the end of the first magnet. It looks as light shining through the wall. No excess of events above the background was detected at this arrangement. Nevertheless, this result extends the exclusion region for the axion mass. The second method wants to measure the ultra-fine vacuum magnetic birefringence for the first time. An optical scheme with electro-optical modulator has been proposed, validated and subsequently improved. Cotton–Mouton constant for air was determined in this experiment setup.

  9. Constraining the axion-photon coupling with massive stars.

    Science.gov (United States)

    Friedland, Alexander; Giannotti, Maurizio; Wise, Michael

    2013-02-08

    We point out that stars in the mass window ~8-12M([circumpunct]) can serve as sensitive probes of the axion-photon interaction, g(Aγγ). Specifically, for these stars axion energy losses from the helium-burning core would shorten and eventually eliminate the blue loop phase of the evolution. This would contradict observational data, since the blue loops are required, e.g., to account for the existence of Cepheid stars. Using the MESA stellar evolution code, modified to include the extra cooling, we conservatively find g(Aγγ)

  10. Cosmologically safe QCD axion without fine-tuning

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Masaki [Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS; Tokyo Univ., Chiba (Japan). Inst. for Cosmic Ray Research; DESY Hamburg (Germany); Yanagida, Tsutomu T.; Yonekura, Kazuya [Tokyo Univ., Chiba (Japan). Kavli IPMU (WPI), UTIAS

    2015-10-15

    Although QCD axion models are widely studied as solutions to the strong CP problem, they generically confront severe fine-tuning problems to guarantee the anomalous PQ symmetry. In this letter, we propose a simple QCD axion model without any fine-tunings. We introduce an extra dimension and a pair of extra quarks living on two branes separately, which is also charged under a bulk Abelian gauge symmetry. We assume a monopole condensation on our brane at an intermediate scale, which implies that the extra quarks develop the chiral symmetry breaking and the PQ symmetry is broken. In contrast to the original Kim's model, our model explains the origin of the PQ symmetry thanks to the extra dimension and avoids the cosmological domain wall problem because of the chiral symmetry breaking in the Abelian gauge theory.

  11. An invisible axion model with controlled FCNCs at tree level

    Directory of Open Access Journals (Sweden)

    Alejandro Celis

    2015-02-01

    Full Text Available We derive the necessary conditions to build a class of invisible axion models with Flavor Changing Neutral Currents at tree-level controlled by the fermion mixing matrices and present an explicit model implementation. A horizontal Peccei–Quinn symmetry provides a solution to the strong CP problem via the Peccei–Quinn mechanism and predicts a cold dark mater candidate, the invisible axion or familon. The smallness of active neutrino masses can be explained via a type I seesaw mechanism, providing a dynamical origin for the heavy seesaw scale. The possibility to avoid the domain wall problem stands as one of the most interesting features of the type of models considered. Experimental limits relying on the axion–photon coupling, astrophysical considerations and familon searches in rare kaon and muon decays are discussed.

  12. Baryogenesis from strong CP violation and the QCD axion.

    Science.gov (United States)

    Servant, Géraldine

    2014-10-24

    We show that strong CP violation from the QCD axion can be responsible for the matter antimatter asymmetry of the Universe in the context of cold electroweak baryogenesis if the electroweak phase transition is delayed below the GeV scale. This can occur naturally if the Higgs couples to a O(100)  GeV dilaton, as expected in some models where the Higgs is a pseudo-Nambu-Goldstone boson of a new strongly interacting sector at the TeV scale. The existence of such a second scalar resonance with a mass and properties similar to the Higgs boson will soon be tested at the LHC. In this context, the QCD axion would not only solve the strong CP problem, but also the matter antimatter asymmetry and dark matter.

  13. Cosmologically Safe QCD Axion without Fine-Tuning.

    Science.gov (United States)

    Yamada, Masaki; Yanagida, Tsutomu T; Yonekura, Kazuya

    2016-02-05

    Although QCD axion models are widely studied as solutions to the strong CP problem, they generically confront severe fine-tuning problems to guarantee the anomalous Peccei-Quinn (PQ) symmetry. In this Letter, we propose a simple QCD axion model without any fine-tunings. We introduce an extra dimension and a pair of extra quarks living on two branes separately, which is also charged under a bulk Abelian gauge symmetry. We assume a monopole condensation on our brane at an intermediate scale, which implies that the extra quarks develop chiral symmetry breaking and the PQ symmetry is broken. In contrast to Kim's original model, our model explains the origin of the PQ symmetry thanks to the extra dimension and avoids the cosmological domain wall problem because of chiral symmetry breaking in Abelian gauge theory.

  14. Axion cosmology, lattice QCD and the dilute instanton gas

    Directory of Open Access Journals (Sweden)

    Sz. Borsanyi

    2016-01-01

    Full Text Available Axions are one of the most attractive dark matter candidates. The evolution of their number density in the early universe can be determined by calculating the topological susceptibility χ(T of QCD as a function of the temperature. Lattice QCD provides an ab initio technique to carry out such a calculation. A full result needs two ingredients: physical quark masses and a controlled continuum extrapolation from non-vanishing to zero lattice spacings. We determine χ(T in the quenched framework (infinitely large quark masses and extrapolate its values to the continuum limit. The results are compared with the prediction of the dilute instanton gas approximation (DIGA. A nice agreement is found for the temperature dependence, whereas the overall normalization of the DIGA result still differs from the non-perturbative continuum extrapolated lattice results by a factor of order ten. We discuss the consequences of our findings for the prediction of the amount of axion dark matter.

  15. The topological susceptibility in finite temperature QCD and axion cosmology

    Science.gov (United States)

    Petreczky, Peter; Schadler, Hans-Peter; Sharma, Sayantan

    2016-11-01

    We study the topological susceptibility in 2 + 1 flavor QCD above the chiral crossover transition temperature using Highly Improved Staggered Quark action and several lattice spacings corresponding to temporal extent of the lattice, Nτ = 6 , 8 , 10 and 12. We observe very distinct temperature dependences of the topological susceptibility in the ranges above and below 250 MeV. While for temperatures above 250 MeV, the dependence is found to be consistent with dilute instanton gas approximation, at lower temperatures the fall-off of topological susceptibility is milder. We discuss the consequence of our results for cosmology wherein we estimate the bounds on the axion decay constant and the oscillation temperature if indeed the QCD axion is a possible dark matter candidate.

  16. Axionic dark matter signatures in various halo models

    Directory of Open Access Journals (Sweden)

    J.D. Vergados

    2017-02-01

    Full Text Available In the present work we study possible signatures in the Axion Dark Matter searches. We focus on the dependence of the expected width in resonant cavities for various popular halo models, leading to standard velocity distributions, e.g. Maxwell–Boltzmann, as well as phase-mixed and non-virialized axionic dark matter (flows, caustic rings. We study, in particular, the time dependence of the resonance width (modulation arising from such models. We find that the difference between the maximum (in June and the minimum (in December can vary by about 10% in the case of standard halos. In the case of mixed phase halos the variation is a bit bigger and for caustic rings the maximum is expected to occur a bit later. Experimentally such a modulation is observable with present technology.

  17. Non-Gaussianity in axion N-flation models.

    Science.gov (United States)

    Kim, Soo A; Liddle, Andrew R; Seery, David

    2010-10-29

    We study perturbations in the multifield axion N-flation model, taking account of the full cosine potential. We find significant differences from previous analyses which made a quadratic approximation to the potential. The tensor-to-scalar ratio and the scalar spectral index move to lower values, which nevertheless provide an acceptable fit to observation. Most significantly, we find that the bispectrum non-Gaussianity parameter f{NL} may be large, typically of order 10 for moderate values of the axion decay constant, increasing to of order 100 for decay constants slightly smaller than the Planck scale. Such a non-Gaussian fraction is detectable. We argue that this property is generic in multifield models of hilltop inflation.

  18. Axion Dark Matter Coupling to Resonant Photons via Magnetic Field.

    Science.gov (United States)

    McAllister, Ben T; Parker, Stephen R; Tobar, Michael E

    2016-04-22

    We show that the magnetic component of the photon field produced by dark matter axions via the two-photon coupling mechanism in a Sikivie haloscope is an important parameter passed over in previous analysis and experiments. The interaction of the produced photons will be resonantly enhanced as long as they couple to the electric or magnetic mode structure of the haloscope cavity. For typical haloscope experiments the electric and magnetic couplings are equal, and this has implicitly been assumed in past sensitivity calculations. However, for future planned searches such as those at high frequency, which synchronize multiple cavities, the sensitivity will be altered due to different magnetic and electric couplings. We define the complete electromagnetic form factor and discuss its implications for current and future dark matter axion searches over a wide range of masses.

  19. Gravitational leptogenesis in axion inflation with SU(2) gauge field

    Science.gov (United States)

    Maleknejad, Azadeh

    2016-12-01

    We present an intrinsic leptogenesis mechanism in models of axion inflation with a classical SU(2) gauge field. The gauge field is coupled to the axion with a Chern-Simons interaction and comprises a tiny fraction of the total energy, ρYM/ρtot lesssim epsilon2. However, it has spin-2 fluctuations which breaks the parity and leads to the generation of chiral gravitational waves during inflation. By the gravitational anomaly in SM, it naturally creates a net lepton number density, sufficient to explain the matter asymmetry. We show that this mechanism can generate the observed value of baryon to photon number density in a natural range of parameters and yet has a small chiral tensor power spectrum on large scales.

  20. Axion and dilaton + metric emerge from local and linear electrodynamics

    CERN Document Server

    Hehl, Friedrich W

    2016-01-01

    We take a quick look at the different possible universally coupled scalar fields in nature. Then, we discuss how the gauging of the group of scale transformations (dilations), together with the Poincare group, leads to a Weyl-Cartan spacetime structure. There the dilaton field finds a natural surrounding. Moreover, we describe shortly the phenomenology of the hypothetical axion field. --- In the second part of our essay, we consider a spacetime, the structure of which is exclusively specified by the premetric Maxwell equations and a fourth rank electromagnetic response tensor density $\\chi^{ijkl}= -\\chi^{jikl}= -\\chi^{ijlk}$ with 36 independent components. This tensor density incorporates the permittivities, permeabilities, and the magneto-electric moduli of spacetime. No metric, no connection, no further property is prescribed. If we forbid birefringence (double-refraction) in this model of spacetime, we eventually end up with the fields of an axion, a dilaton, and the 10 components of a metric tensor with L...

  1. An automatic invisible axion in the SUSY preon model

    Science.gov (United States)

    Babu, K. S.; Choi, Kiwoon; Pati, J. C.; Zhang, X.

    1994-08-01

    It is shown that the recently proposed preon model which provides a unified origin of the diverse mass scales and an explanation of family replication as well as of inter-family mass-hierarchy, naturally possesses a Peccei-Quinn (PQ) symmetry whose spontaneous breaking leads to an automatic invisible axion. Existence of the PQ-symmetry is simply a consequence of supersymmetry and the requirement of minimality in the field-content and interactions, which proposes that the lagrangian should possess only those terms which are dictated by the gauge principle and no others. In addition to the axion, the model also generates two superlight Goldstone bosons and their superpartners all of which are cosmologically safe.

  2. Cosmologically safe QCD axion without fine-tuning

    CERN Document Server

    Yamada, Masaki; Yonekura, Kazuya

    2015-01-01

    Although QCD axion models are widely studied as solutions to the strong CP problem, they generically confront severe fine-tuning problems to guarantee the anomalous PQ symmetry. In this letter, we propose a simple QCD axion model without any fine-tunings. We introduce an extra dimension and a pair of extra quarks living on two branes separately, which is also charged under a bulk Abelian gauge symmetry. We assume a monopole condensation on our brane at an intermediate scale, which implies that the extra quarks develop the chiral symmetry breaking and the PQ symmetry is broken. In contrast to the original Kim's model, our model explains the origin of the PQ symmetry thanks to the extra dimension and avoids the cosmological domain wall problem because of the chiral symmetry breaking in the Abelian gauge theory.

  3. Axion monodromy inflation with multi-natural modulations

    CERN Document Server

    Higaki, Tetsutaro; Seto, Osamu; Yamaguchi, Yuya

    2014-01-01

    We study parameter space in the axion monodromy inflation corrected by dynamically generated terms involving with the axion. The potential has the linear potential with multiple sinusoidal functions, which play a role in generating modulations. We show that this potential leads both to a large tensor-to-scalar ratio $r_T \\sim 0.16$ and to a large negative running of spectral index $\\alpha_s \\sim - (0.02 -0.03)$. To realize these results, a small hierarchy among dynamical scales is required whereas the decay constants in sinusoidal functions remain sub-Planckian in this model. We discuss also reheating process after the inflation in a bottom-up approach.

  4. Team Teaching.

    Science.gov (United States)

    Bunyan, L. W.

    The purpose of this study was to review current developments in team teaching and to assess its potential in the Calgary, Alberta, schools. An investigation into team teaching situations in schools in the eastern half of the United States and Canada revealed characteristics common to successful programs (e.g., charismatic leadership and innovative…

  5. The quest for axions and other new light particles

    Energy Technology Data Exchange (ETDEWEB)

    Baker, K. [Yale Univ., New Haven, CT (United States). Physics Dept.; Cantatore, G. [Trieste Univ. (Italy); INFN Trieste (Italy); Cetin, S.A. [Dogus Univ., Istanbul (Turkey)] [and others; Collaboration: Working Group

    2013-05-15

    Standard Model extensions often predict low-mass and very weakly interacting particles, such as the axion. A number of small-scale experiments at the intensity/ precision frontier are actively searching for these elusive particles, complementing searches for physics beyond the Standard Model at colliders. Whilst a next generation of experiments will give access to a huge unexplored parameter space, a discovery would have a tremendous impact on our understanding of fundamental physics.

  6. Relativistic soliton collisions of axion type dark matter

    Directory of Open Access Journals (Sweden)

    David Castañeda Valle

    2016-07-01

    Full Text Available Axion-like scalar fields and the Lane–Emden (LE truncation of their periodic potential are analyzed as a toy model of dark matter halos. Then, collisions of the well-known kinks in (1+1 spacetime dimensions can be mapped to those of localized lumps of the LE equation. Here, we generalize this mapping to (2+1D or even (3+1D and discuss a challenging intrinsic inelastic effect during relativistic soliton collisions.

  7. Holographic transports and stability in anisotropic linear axion model

    CERN Document Server

    Ge, Xian-Hui; Niu, Chao; Sin, Sang-Jin

    2014-01-01

    We study thermoelectric conductivities and shear viscosities in a holographically anisotropic model. Momentum relaxation is realized through perturbing the linear axion field. AC conductivity exhibits a conherent/incoherent metal transition. The longitudinal shear viscosity for prolate anisotropy violates the bound conjectured by Kovtun-Son-Starinets. We also find that thermodynamic and dynamical instabilities are not always equivalent, which provides a counter example of the Gubser-Mitra conjecture.

  8. 2016 U.S. Department of Energy Race to Zero Student Design Competition Guide

    Energy Technology Data Exchange (ETDEWEB)

    2016-03-01

    This Guide to the Race to Zero Student Design Competition is a comprehensive overview of the framework, timeline, design parameters, judging criteria, and awards. This Guide provides links to resources that the teams will need.

  9. Axion Induced Oscillating Electric Dipole Moment of the Electron

    CERN Document Server

    Hill, Christopher T

    2016-01-01

    The axion electromagnetic anomaly induces an oscillating electric dipole for the electron of frequency $m_a$ and strength $\\sim 10^{-32}$ e-cm, two orders of magnitude above the nucleon, and within four orders of magnitude of the present standard model constant limit. We give a detailed study of this phenomenon via the interaction of the cosmic axion, through the electromagnetic anomaly, with particular emphasis on the decoupling limit of the axion, $\\partial_t a(t)\\propto m_a \\rightarrow 0$. The general form of the action involves a local contact interaction and a nonlocal contribution that enforces the decoupling limit. We derive the effective action in the Pauli-Schroedinger non-relativistic formalism, and in Georgi's heavy quark formalism adapted to the "heavy electron" (heavy compared to $m_a$). We compute the electric dipole radiation emitted by stationary electrons, and we discuss a number of experimental configurations that may yield detectable signals. Phased array radiators with $N^2$ unit cell magn...

  10. Gauge-preheating and the end of axion inflation

    CERN Document Server

    Adshead, Peter; Scully, Timothy R; Sfakianakis, Evangelos I

    2015-01-01

    We study the onset of the reheating epoch at the end of axion-driven inflation where the axion is coupled to an Abelian, $U(1)$, gauge field via a Chern-Simons interaction term. We focus primarily on $m^2\\phi^2$ inflation and explore the possibility that preheating can occur for a range of coupling values consistent with recent observations and bounds on the overproduction of primordial black holes. We find that for a wide range of parameters preheating is efficient. In certain cases the inflaton is seen to transfer all its energy to the gauge fields within a few oscillations. We find that the gauge fields on sub-horizon scales end in an unpolarized state, due to the existence of strong rescattering between the inflaton and gauge modes. We also present a preliminary study of an axion monodromy model coupled to $U(1)$ gauge fields, seeing a similarly efficient preheating behavior as well as indications that the coupling strength has an effect on the creation of oscillons.

  11. Systematics of Axion Inflation in Calabi-Yau Hypersurfaces

    CERN Document Server

    Long, Cody; Stout, John

    2016-01-01

    We initiate a comprehensive survey of axion inflation in compactifications of type IIB string theory on Calabi-Yau hypersurfaces in toric varieties. For every threefold with $h^{1,1} \\le 4$ in the Kreuzer-Skarke database, we compute the metric on K\\"ahler moduli space, as well as the matrix of four-form axion charges of Euclidean D3-branes on rigid divisors. These charges encode the possibility of enlarging the field range via alignment. We then determine an upper bound on the inflationary field range $\\Delta \\phi$ that results from the leading instanton potential, in the absence of monodromy. The bound on the field range in this ensemble is $\\Delta \\phi \\lesssim 0.3 M_{\\rm{pl}}$, in a compactification where the smallest curve volume is $(2\\pi)^2\\alpha'$, and we argue that the sigma model expansion is adequately controlled. The largest increase resulting from alignment is a factor $\\approx 2.6$. We also examine a set of threefolds with $h^{1,1}$ up to $100$ and characterize their axion charge matrices. We dis...

  12. Cosmology of Axions and Moduli: A Dynamical Systems Approach

    CERN Document Server

    Marsh, David J E; Copeland, Edmund J; Ferreira, Pedro G

    2012-01-01

    This paper is concerned with string cosmology and the dynamics of multiple scalar fields in potentials that can become negative, and their features as (Early) Dark Energy models. Our point of departure is the "String Axiverse", a scenario that motivates the existence of cosmologically light axion fields as a generic consequence of string theory. We couple such an axion to its corresponding modulus. We give a detailed presentation of the rich cosmology of such a model, ranging from the setting of initial conditions on the fields during inflation, to the asymptotic future. We present some simplifying assumptions based on the fixing of the axion decay constant $f_a$, and on the effective field theory when the modulus trajectory is adiabatic, and find the conditions under which these assumptions break down. As a by-product of our analysis, we find that relaxing the assumption of fixed $f_a$ leads to the appearance of a new meta-stable de-Sitter region for the modulus without the need for uplifting by an additiona...

  13. Oscillations in the CMB from Axion Monodromy Inflation

    Energy Technology Data Exchange (ETDEWEB)

    Flauger, Raphael; /Texas U.; McAllister, Liam; Pajer, Enrico; /Cornell U., Phys. Dept.; Westphal, Alexander; /SLAC /Stanford U., Phys. Dept.; Xu, Gang; /Cornell U., Phys. Dept.

    2011-12-01

    We study the CMB observables in axion monodromy inflation. These well-motivated scenarios for inflation in string theory have monomial potentials over super-Planckian field ranges, with superimposed sinusoidal modulations from instanton effects. Such periodic modulations of the potential can drive resonant enhancements of the correlation functions of cosmological perturbations, with characteristic modulations of the amplitude as a function of wavenumber. We give an analytical result for the scalar power spectrum in this class of models, and we determine the limits that present data places on the amplitude and frequency of modulations. Then, incorporating an improved understanding of the realization of axion monodromy inflation in string theory, we perform a careful study of microphysical constraints in this scenario. We find that detectable modulations of the scalar power spectrum are commonplace in well-controlled examples, while resonant contributions to the bispectrum are undetectable in some classes of examples and detectable in others. We conclude that resonant contributions to the spectrum and bispectrum are a characteristic signature of axion monodromy inflation that, in favorable cases, could be detected in near-future experiments.

  14. Unbiased constraints on ultralight axion mass from dwarf spheroidal galaxies

    CERN Document Server

    Gonzáles-Morales, Alma X; Peñarrubia, Jorge; Ureña-López, Luis

    2016-01-01

    It has been suggested that the internal dynamics of dwarf spheroidal galaxies (dSphs) can be used to test whether or not ultralight axions with $m_a\\sim 10^{-22}\\text{eV}$ are a preferred dark matter candidate. However, comparisons to theoretical predictions tend to be inconclusive for the simple reason that while most cosmological models consider only dark matter, one observes only baryons. Here we use realistic kinematic mock data catalogs of Milky Way dSph's to show that the "mass-anisotropy degeneracy" in the Jeans equations leads to biased bounds on the axion mass in galaxies with unknown dark matter halo profiles. In galaxies with multiple chemodynamical components this bias can be partly removed by modelling the mass enclosed within each subpopulation. However, analysis of the mock data reveals that the least-biased constraints on the axion mass result from fitting the luminosity-averaged velocity dispersion of the individual chemodynamical components directly. Applying our analysis to two dSph's with ...

  15. Three-Form Gauging of axion Symmetries and Gravity

    CERN Document Server

    Dvali, Gia

    2005-01-01

    Nonlinearly realized Abelian global symmetries can be reformulated as local shift symmetries gauged by three-form gauge fields. The anomalous symmetries of the Standard Model (such as Peccei-Quinn or $B+L$) can be dualized to local symmetries gauged by the Chern-Simons three-forms of the Standard Model gauge group. In this description the strong CP problem can be reformulated as the problem of a massless three-form field in QCD, which creates an arbitrary CP-violating constant four-form electric field in the vacuum. Both the axion as well as the massless quark solutions amount to simply Higgsing the three-form gauge field, hence screening the electric field in the vacuum. This language gives an alternative way for visualizing the physics of the axion solution as well as the degree of its vulnerability due to gravitational corrections. Any physics that can jeopardize the axion solution must take the QCD three-form out of the Higgs phase. This can only happen if the physics in question provides an additional ma...

  16. Axions and the cooling of white dwarf stars

    CERN Document Server

    Isern, J; Torres, S; Catalan, S

    2008-01-01

    White dwarfs are the end-product of the lifes of intermediate- and low-mass stars and their evolution is described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision their luminosity function, that is, the number of stars per unit volume and luminosity interval. We show here that the shape of the bright branch of this function is only sensitive to the averaged cooling rate of white dwarfs and we propose to use this property to check the possible existence of axions, a proposed but not yet detected weakly interacting particle. Our results indicate that the inclusion of the emission of axions in the evolutionary models of white dwarfs noticeably improves the agreement between the theoretical calculations and the observational white dwarf luminosity function. The best fit is obtained for m_a cos^2 \\beta ~ 5 meV, where m_a is the mass of the axion and cos^2 \\beta is a free parameter. We also show that values larger than 10 meV are clearly excluded. The existin...

  17. Axion-Assisted Production of Sterile Neutrino Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Berlin, Asher [Chicago U.; Hooper, Dan [Chicago U., KICP

    2016-10-12

    Sterile neutrinos can be generated in the early universe through oscillations with active neutrinos and represent a popular and well-studied candidate for our universe's dark matter. Stringent constraints from X-ray and gamma-ray line searches, however, have excluded the simplest of such models. In this letter, we propose a novel alternative to the standard scenario in which the mixing angle between the sterile and active neutrinos is a dynamical quantity, induced through interactions with a light axion-like field. As the energy density of the axion-like particles is diluted by Hubble expansion, the degree of mixing is reduced at late times, suppressing the decay rate and easily alleviating any tension with X-ray or gamma-ray constraints. We present a simple model which illustrates the phenomenology of this scenario, and also describe a framework in which the QCD axion is responsible for the production of sterile neutrinos in the early universe.

  18. DIFFERENT DIMENSIONS OF TEAMS

    Directory of Open Access Journals (Sweden)

    Goparaju Purna SUDHAKAR

    2014-01-01

    Full Text Available Popularity ofteams is growing in 21st Century. Organizations are getting theirwork done through different types of teams. Teams have proved that thecollective performance is more than the sum of the individual performances.Thus, the teams have got different dimensions such as quantitative dimensionsand qualitative dimensions. The Quantitative dimensions of teams such as teamperformance, team productivity, team innovation, team effectiveness, teamefficiency, team decision making and team conflicts and Qualitative dimensionsof teams such as team communication, team coordination, team cooperation, teamcohesion, team climate, team creativity, team leadership and team conflictshave been discussed in this article.

  19. Can the Axions of Standard--like Superstring Models Solve the Strong CP Problem?

    CERN Document Server

    Halyo, E

    1993-01-01

    We find that there are three axions in standard--like superstring models in the four dimensional free fermionic formulation. These axions are either harmful or very heavy. Therefore, they cannot solve the strong CP problem. We show that this is a general result in superstring models with chiral generations from the $Z_2$ twisted sectors which use a $Z_4$ twist.

  20. On the validity of the perturbative description of axions during inflation

    DEFF Research Database (Denmark)

    Ferreira, Ricardo J. Z.; Ganc, Jonathan; Noreña, Jorge;

    2016-01-01

    Axions play a central role in many realizations of large field models of inflation and in recent alternative mechanisms for generating primordial tensor modes in small field models. If these axions couple to gauge fields, the coupling produces a tachyonic instability that leads to an exponential...

  1. Constraints on Axions and Axionlike Particles from Fermi Large Area Telescope Observations of Neutron Stars

    CERN Document Server

    Berenji, Bijan; Meyer, Manuel

    2016-01-01

    We present constraints on the nature of axions and axionlike particles (ALPs) by analyzing gamma--ray data from neutron stars using the Fermi Large Area Telescope. In addition to axions solving the strong CP problem of particle physics, axions and ALPs are also possible dark matter candidates. We investigate axions and ALPs produced by nucleon--nucleon bremsstrahlung within neutron stars. We derive a phenomenological model for the gamma--ray spectrum arising from subsequent axion decays. By analyzing 5 years of gamma-ray data (between 60 MeV and 200 MeV) for a sample of 4 nearby neutron stars, we do not find evidence for an axion or ALP signal, thus we obtain a combined 95\\% confidence level upper limit on the axion mass of 7.9$\\times 10^{-2}$ eV, which corresponds to a lower limit for the Peccei-Quinn scale $f_a$ of 7.6$\\times 10^7$ GeV. Our constraints are more stringent than previous results probing the same physical process, and are competitive with results probing axions and ALPs by different mechanisms.

  2. An update on the Axion Helioscopes front: Current activities at CAST and the IAXO project

    DEFF Research Database (Denmark)

    Dafni, T.; Arik, M.; Armengaud, E.;

    2016-01-01

    Although they have not yet been detected, axions and axion-like particles (ALPs) continue to maintain the interest (even increasingly so) of the rare-event searches community as viable candidates for the Dark Matter of the Universe but also as a solution for several other puzzles of astrophysics...

  3. The asymmetry and the diurnal variation in axionic dark matter searches

    CERN Document Server

    Semertzidis, Y

    2014-01-01

    In the present work we propose to study the modulation signal in Axion Dark Matter searches. This can be seen in directional experiments employing cylindrical resonant cavities, which exploit the axion photon-conversion in the presence of strong magnetic fields

  4. Determination of effective axion masses in the helium-3 buffer of CAST

    Energy Technology Data Exchange (ETDEWEB)

    Ruz, J

    2011-11-18

    The CERN Axion Solar Telescope (CAST) is a ground based experiment located in Geneva (Switzerland) searching for axions coming from the Sun. Axions, hypothetical particles that not only could solve the strong CP problem but also be one of the favored candidates for dark matter, can be produced in the core of the Sun via the Primakoff effect. They can be reconverted into X-ray photons on Earth in the presence of strong electromagnetic fields. In order to look for axions, CAST points a decommissioned LHC prototype dipole magnet with different X-ray detectors installed in both ends of the magnet towards the Sun. The analysis of the data acquired during the first phase of the experiment yielded the most restrictive experimental upper limit on the axion-to-photon coupling constant for axion masses up to about 0.02 eV/c{sup 2}. During the second phase, CAST extends its mass sensitivity by tuning the electron density present in the magnetic field region. Injecting precise amounts of helium gas has enabled CAST to look for axion masses up to 1.2 eV/c{sup 2}. This paper studies the determination of the effective axion masses scanned at CAST during its second phase. The use of a helium gas buffer at temperatures of 1.8 K has required a detailed knowledge of the gas density distribution. Complete sets of computational fluid dynamic simulations validated with experimental data have been crucial to obtain accurate results.

  5. The search for axion-like dark matter using magnetic resonance

    Science.gov (United States)

    Sushkov, Alexander; Casper Collaboration

    2016-05-01

    The nature of dark matter is one of the most important open problems in modern physics, and it is necessary to develop techniques to search for a wide class of dark-matter candidates. Axions, originally introduced to resolve the strong CP problem in quantum chromodynamics (QCD), and axion-like particles (ALPs) are strongly motivated dark matter candidates. Nuclear spins interacting with axion-like background dark matter experience an energy shift, oscillating at the frequency equal to the axion Compton frequency. The Cosmic Axion Spin Precession Experiments (CASPEr) use precision magnetometry and nuclear magnetic resonance techniques to search for the effects of this interaction. The experimental signature is precession of the nuclear spins under the condition of magnetic resonance: when the bias magnetic field is tuned such that the nuclear spin sublevel splitting is equal to the axion Compton frequency. These experiments have the potential to detect axion-like dark matter in a wide mass range (10-12 eV to 10-6 eV, scanned by changing the bias magnetic field from approximately 1 gauss to 20 tesla) and with coupling strengths many orders of magnitude beyond the current astrophysical and laboratory limits, and all the way down to those corresponding to the QCD axion. Supported by the Heising-Simons Foundation.

  6. Tensor interpretation of BICEP2 results severely constrains axion dark matter.

    Science.gov (United States)

    Marsh, David J E; Grin, Daniel; Hlozek, Renée; Ferreira, Pedro G

    2014-07-04

    The recent detection of B modes by the BICEP2 experiment has nontrivial implications for axion dark matter implied by combining the tensor interpretation with isocurvature constraints from Planck observations. In this Letter the measurement is taken as fact, and its implications considered, though further experimental verification is required. In the simplest inflation models, r=0.2 implies HI=1.1×10(14)  GeV. If the axion decay constant faaxion as DM for ma≲52χ6/7  μeV (where χ>1 accounts for theoretical uncertainty). If fa>HI/2π then vacuum fluctuations of the axion field place conflicting demands on axion DM: isocurvature constraints require a DM abundance which is too small to be reached when the backreaction of fluctuations is included. High-fa QCD axions are thus ruled out. Constraints on axionlike particles, as a function of their mass and DM fraction, are also considered. For heavy axions with ma≳10(-22)  eV we find Ωa/Ωd≲10(-3), with stronger constraints on heavier axions. Lighter axions, however, are allowed and (inflationary) model-independent constraints from the CMB temperature power spectrum and large scale structure are stronger than those implied by tensor modes.

  7. Axionic domain wall number related to U(1anom global symmetry

    Directory of Open Access Journals (Sweden)

    Jihn E. Kim

    2016-08-01

    Full Text Available The QCD axion with fa at an intermediate scale, 109 GeV∼1012 GeV, seems in conflict with the gravity spoil of global symmetries and may face the axionic domain wall problem. We point out that the string compactifications with an anomalous U(1 gauge symmetry, allowing desirable chiral matter spectra, circumvent these two problems simultaneously.

  8. Exotic axion cosmology in theories with phase transitions below the QCD scale.

    Science.gov (United States)

    Kaplan, David B; Zurek, Kathryn M

    2006-02-03

    We show that axion phenomenology may be significantly different than conventionally assumed in theories which exhibit late phase transitions (below the QCD scale). In such theories, one can find multiple pseudoscalars with axionlike couplings to matter, including a string scale axion, whose decay constant far exceeds the conventional cosmological bound. Such theories have several dark matter candidates.

  9. Solar Axion search with Micromegas detectors in the CAST Experiment with $^{3}$He as buffer gas

    CERN Document Server

    Garcia Pascual, Juan Antonio

    2015-01-01

    Axions are well motivated particles proposed in an extension of the Standard Model (SM) as a solution to the CP problem in strong interactions. On the other hand, there is the category of axion-like particles (ALPs) which appear in diverse extensions of the SM and share the same phenomenology of the axion. Axions and ALPs are hypothetical neutral particles that interact weakly with matter, being candidates to solve the Dark Matter problem. CAST, the CERN Axion Solar Telescope is looking for solar axions since 2003. CAST exploit the helioscope technique using a decommissioned LHC dipole magnet in which solar axions could be reconverted into photons. The magnet is mounted on a movable platform that allows tracking the Sun $\\sim$1.5 hours during sunset and during sunrise. The axion signal would be an excess of X-rays in the detectors located at the magnet bore ends and thus low background detectors are mandatory. Three of the four detectors operating at CAST are of the Micromegas type. The analysis of the data o...

  10. Tire Changes, Fresh Air, and Yellow Flags: Challenges in Predictive Analytics for Professional Racing.

    Science.gov (United States)

    Tulabandhula, Theja; Rudin, Cynthia

    2014-06-01

    Our goal is to design a prediction and decision system for real-time use during a professional car race. In designing a knowledge discovery process for racing, we faced several challenges that were overcome only when domain knowledge of racing was carefully infused within statistical modeling techniques. In this article, we describe how we leveraged expert knowledge of the domain to produce a real-time decision system for tire changes within a race. Our forecasts have the potential to impact how racing teams can optimize strategy by making tire-change decisions to benefit their rank position. Our work significantly expands previous research on sports analytics, as it is the only work on analytical methods for within-race prediction and decision making for professional car racing.

  11. Search for solar axions with CsI(Tl) crystal detectors

    CERN Document Server

    Yoon, Y S; Bhang, H; Choi, J H; Choi, S; Hahn, I S; Jeon, E J; Joo, H W; Kang, W G; Kim, B H; Kim, G B; Kim, H J; Kim, K W; Kim, S C; Kim, S K; Kim, Y D; Kim, Y H; Lee, H S; Lee, J H; Lee, J K; Lee, S J; Leonard, D S; Li, J; Myung, S S; Olsen, S L; So, J H

    2016-01-01

    The results of a search for solar axions from the Korea Invisible Mass Search (KIMS) experiment at the Yangyang Underground Laboratory are presented. Low-energy electron-recoil events would be produced by conversion of solar axions into electrons via the axio-electric effect in CsI(Tl) crystals. Using data from an exposure of 34,596 $\\rm kg \\cdot days$, we set a 90 \\% confidence level upper limit on the axion-electron coupling, $g_{ae}$, of $1.39 \\times 10^{-11}$ for an axion mass less than 1 keV/$\\rm c^2$. This limit is lower than the indirect solar neutrino bound, and fully excludes QCD axions heavier than 0.48 eV/$\\rm c^2$ and 140.9 eV/$\\rm c^2$ for the DFSZ and KSVZ models respectively.

  12. The QUAX proposal: a search of galactic axion with magnetic materials

    CERN Document Server

    Ruoso, Giuseppe; Ortolan, Antonello; Pengo, Ruggero; Braggio, Caterina; Carugno, Giovanni; Gallo, Carmelo Sebastiano; Speake, Clive C.

    2015-01-01

    Aim of the QUAX (QUaerere AXion) proposal is to exploit the interaction of cosmological axions with the spin of electrons in a magnetized sample. Their effect is equivalent to the application of an oscillating rf field with frequency and amplitude which are fixed by axion mass and coupling constant, respectively. The rf receiver module of the QUAX detector consists of magnetized samples with the Larmor resonance frequency tuned to the axion mass by a polarizing static magnetic field. The interaction of electrons with the axion-equivalent rf field produces oscillations in the total magnetization of the samples. To amplify such a tiny field, a pump field at the same frequency is applied in a direction orthogonal to the polarizing field. The induced oscillatory magnetization along the polarizing field is measured by a SQUID amplifier operated at its quantum noise level.

  13. Probing axions with the neutrino signal from the next galactic supernova

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Tobias [Wroclaw Univ. (Poland). Inst. for Theoretical Physics; Chakraborty, Sovan [Indian Institute of Technology Guwahati, Assam (India). Dept. of Physics; Max-Planck-Institut fuer Physik, Muenchen (Germany); Giannotti, Maurizio [Barry Univ., Miami Shores, FL (United States). Physical Sciences; Mirizzi, Alessandro [Dipartimento Interateneo di Fisica ' ' Michelangelo Merlin' ' , Bari (Italy); Istituto Nazionale di Fisica Nucleare, Bari (Italy); Payez, Alexandre; Ringwald, Andreas [DESY Hamburg (Germany). Theory Group

    2016-05-15

    We study the impact of axion emission in simulations of massive star explosions, as an additional source of energy loss complementary to the standard neutrino emission. The inclusion of this channel shortens the cooling time of the nascent protoneutron star and hence the duration of the neutrino signal. We treat the axion-matter coupling strength as a free parameter to study its impact on the protoneutron star evolution as well as on the neutrino signal. We furthermore analyze the observability of the enhanced cooling in current and next-generation underground neutrino detectors, showing that values of the axion mass m{sub a}>or similar 8 x 10{sup -3} eV can be probed. Therefore a galactic supernova neutrino observation would provide a valuable possibility to probe axion masses in a range within reach of the planned helioscope experiment, the International Axion Observatory (IAXO).

  14. The 7 keV axion dark matter and the X-ray line signal

    Energy Technology Data Exchange (ETDEWEB)

    Higaki, Tetsutaro [KEK, Tsukuba (Japan). Theory Center; Jeong, Kwang Sik [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Takahashi, Fuminobu [Tohoku Univ., Sendai (Japan). Dept. of Physics; Tokyo Univ., Kashiwa (Japan). Kavli IPMU, TODIAS

    2014-03-15

    We propose a scenario where the saxion dominates the energy density of the Universe and reheats the standard model sector via the dilatonic coupling, while its axionic partner contributes to dark matter decaying into photons via the same operator in supersymmetry. Interestingly, for the axion mass m{sub a} ≅ 7 keV and the decay constant f{sub a} ≅10{sup 14-15} GeV, the recently discovered X-ray line at 3.5 keV in the XMM Newton X-ray observatory data can be explained. We discuss various cosmological aspects of the 7 keV axion dark matter such as the production of axion dark matter, the saxion decay process, hot dark matter and isocurvature constraints on the axion dark matter, and the possible baryogenesis scenarios.

  15. Evolution and thermalization of dark matter axions in the condensed regime

    CERN Document Server

    Saikawa, Ken'ichi

    2012-01-01

    We discuss the possibility that dark matter axions form a Bose-Einstein condensate (BEC) due to the gravitational self-interactions. The formation of BEC occurs in the condensed regime, where the transition rate between different momentum states is large compared to the energy exchanged in the transition. The time evolution of the quantum state occupation number of axions in the condensed regime is derived based on the in-in formalism. We recover the expression for the thermalization rate due to self-interaction of the axion field, which was obtained in the other literature. It is also found that the leading order contributions for interactions between axions and other species vanish, which implies that the axion BEC does not give any significant modifications on standard cosmological parameters.

  16. Possible resonance effect of axionic dark matter in S/N/S Josephson junctions

    CERN Document Server

    Beck, Christian

    2013-01-01

    We provide theoretical arguments that dark matter axions from the galactic halo that pass through the earth may generate a small observable signal in resonant S/N/S Josephson junctions. The corresponding interaction process is based on uniqueness of the gauge-invariant axion Josephson phase angle modulo 2 pi and is predicted to produce a small Shapiro step-like feature without externally applied microwave radiation when the Josephson frequency resonates with the axion mass. A resonance signal of so far unknown origin observed in [C. Hoffmann et al. PRB 70, 180503(R) (2004)] is consistent with our theory and can be interpreted in terms of an axion mass of 0.11 meV and a local galactic axionic dark matter density of 0.05 GeV/cm^3. We discuss future experimental checks to confirm the dark-matter nature of the observed signal.

  17. The 7 keV axion dark matter and the X-ray line signal

    CERN Document Server

    Higaki, Tetsutaro; Takahashi, Fuminobu

    2014-01-01

    Some of light moduli fields may play an important role in cosmology. We consider a scenario where the saxion dominates the energy density of the Universe and reheats the standard model sector via its dilatonic couplings, while its axionic partner contributes to dark matter decaying into photons via the same operator in supersymmery. Interestingly, for the axion mass $m_a \\simeq 7$ keV and the decay constant $f_a \\simeq 10^{14-15}$ GeV, the recently discovered X-ray line at $3.5$ keV in the XMM Newton X-ray observatory data can be explained. We discuss various cosmological aspects of the $7$ keV axion dark matter such as the production of axion dark matter, the saxion decay process, hot dark matter and isocurvature constraints on the axion dark matter, and the possible baryogenesis scenarios.

  18. Search for solar axions with CsI(Tl) crystal detectors

    Science.gov (United States)

    Yoon, Y. S.; Park, H. K.; Bhang, H.; Choi, J. H.; Choi, S.; Hahn, I. S.; Jeon, E. J.; Joo, H. W.; Kang, W. G.; Kim, B. H.; Kim, G. B.; Kim, H. J.; Kim, K. W.; Kim, S. C.; Kim, S. K.; Kim, Y. D.; Kim, Y. H.; Lee, H. S.; Lee, J. H.; Lee, J. K.; Leonard, D. S.; Li, J.; Myung, S. S.; Olsen, S. L.; So, J. H.

    2016-06-01

    The results of a search for solar axions from the Korea Invisible Mass Search (KIMS) experiment at the Yangyang Underground Laboratory are presented. Low-energy electron-recoil events would be produced by conversion of solar axions into electrons via the axio-electric effect in CsI(Tl) crystals. Using data from an exposure of 34,596 kg · days, we set a 90 % confidence level upper limit on the axion-electron coupling, g ae , of 1 .39 × 10 -11 for an axion mass less than 1 keV/c2. This limit is lower than the indirect solar neutrino bound, and fully excludes QCD axions heavier than 0.48 eV/c2 and 140.9 eV/c2 for the DFSZ and KSVZ models respectively.

  19. Probing axions with the neutrino signal from the next Galactic supernova

    Science.gov (United States)

    Fischer, Tobias; Chakraborty, Sovan; Giannotti, Maurizio; Mirizzi, Alessandro; Payez, Alexandre; Ringwald, Andreas

    2016-10-01

    We study the impact of axion emission in simulations of massive star explosions, as an additional source of energy loss complementary to the standard neutrino emission. The inclusion of this channel shortens the cooling time of the nascent protoneutron star and hence the duration of the neutrino signal. We treat the axion-matter coupling strength as a free parameter to study its impact on the protoneutron star evolution as well as on the neutrino signal. We furthermore analyze the observability of the enhanced cooling in current and next-generation underground neutrino detectors, showing that values of the axion mass ma≳8 ×10-3 eV can be probed. Therefore a galactic supernova neutrino observation would provide a valuable possibility to probe axion masses in a range within reach of the planned helioscope experiment, the International Axion Observatory.

  20. Probing axions with the neutrino signal from the next galactic supernova

    CERN Document Server

    Fischer, Tobias; Giannotti, Maurizio; Mirizzi, Alessandro; Payez, Alexandre; Ringwald, Andreas

    2016-01-01

    We study the impact of axion emission in simulations of massive star explosions, as an additional source of energy loss complementary to the standard neutrino emission. The inclusion of this channel shortens the cooling time of the nascent protoneutron star and hence the duration of the neutrino signal. We treat the axion-matter coupling strength as a free parameter to study its impact on the protoneutron star evolution as well as on the neutrino signal. We furthermore analyze the observability of the enhanced cooling in current and next-generation underground neutrino detectors, showing that values of the axion mass $m_a \\gtrsim 8 \\times 10^{-3}$ eV can be probed. Therefore a galactic supernova neutrino observation would provide a valuable possibility to probe axion masses in a range within reach of the planned helioscope experiment the International Axion Observatory (IAXO).

  1. Virtual Teams.

    Science.gov (United States)

    Geber, Beverly

    1995-01-01

    Virtual work teams scattered around the globe are becoming a feature of corporate workplaces. Although most people prefer face-to-face meetings and interactions, reality often requires telecommuting. (JOW)

  2. Search for Solar Axions by the CERN Axion Solar Telescope with 3 He Buffer Gas: Closing the Hot Dark Matter Gap

    CERN Document Server

    Arik, M.; Barth, K.; Belov, A.; Borghi, S.; Bräuninger, H.; Cantatore, G.; Carmona, J.M.; Cetin, S.A.; Collar, J.I.; Da Riva, E.; Dafni, T.; Davenport, M.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Friedrich, P.; Galán, J.; García, J.A.; Gardikiotis, A.; Garza, J.G.; Gazis, E.N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gómez, H.; Gómez Marzoa, M.; Gruber, E.; Guthörl, T.; Hartmann, R.; Hauf, S.; Haug, F.; Hasinoff, M.D.; Hoffmann, D.H.H.; Iguaz, F.J.; Irastorza, I.G.; Jacoby, J.; Jakovčić, K.; Karuza, M.; Königsmann, K.; Kotthaus, R.; Krčmar, M.; Kuster, M.; Lakić, B.; Lang, P.M.; Laurent, J.M.; Liolios, A.; Ljubičić, A.; Lozza, V.; Luzón, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Papaevangelou, T.; Pivovaroff, M.J.; Raffelt, G.; Riege, H.; Rodríguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Silva, P.S.; Solanki, S.K.; Stewart, L.; Tomás, A.; Tsagri, M.; van Bibber, K.; Vafeiadis, T.; Villar, J.; Vogel, J.K.; Yildiz, S.C.; Zioutas, K.

    2014-01-01

    The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 3.3 x 10^{-10} GeV^{-1} at 95% CL, with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g_a, for example by the currently discussed next generation helioscope IAXO.

  3. Nested Multi- and Many-Objective Optimisation of Team Track Pursuit Cycling

    Directory of Open Access Journals (Sweden)

    Markus Wagner

    2016-10-01

    Full Text Available Team pursuit track cycling is an elite sport that is part of the Summer Olympics. Teams race against each other on special tracks called velodromes. In this article, we create racing strategies that allow the team to complete the race in as little time as possible. In addition to the traditional minimisation of the race times, we consider the amount of energy that the riders have left at the end of the race. For the team coach this extension can have the benefit that a diverse set of trade-off strategies can be considered. For the optimisation approach, the added diversity can help to get over local optima.To solve this problem, we apply different state-of-the-art algorithms with problem-specific variation operators. It turns out that nesting algorithms is beneficial for achieving fast strategies reliably.

  4. DIFFERENT DIMENSIONS OF TEAMS

    OpenAIRE

    Sudhakar, Goparaju Purna

    2013-01-01

    Popularity of teams is growing in 21st Century. Organizations are getting their work done through different types of teams. Teams have proved that the collective performance is more than the sum of the individual performances. Thus, the teams have got different dimensions such as quantitative dimensions and qualitative dimensions. The Quantitative dimensions of teams such as team performance, team productivity, team innovation, team effectiveness, team efficiency, team decision making and tea...

  5. Team Learning and Team Composition in Nursing

    Science.gov (United States)

    Timmermans, Olaf; Van Linge, Roland; Van Petegem, Peter; Elseviers, Monique; Denekens, Joke

    2011-01-01

    Purpose: This study aims to explore team learning activities in nursing teams and to test the effect of team composition on team learning to extend conceptually an initial model of team learning and to examine empirically a new model of ambidextrous team learning in nursing. Design/methodology/approach: Quantitative research utilising exploratory…

  6. Biogeographical ancestry and race.

    Science.gov (United States)

    Gannett, Lisa

    2014-09-01

    The use of racial and ethnic categories in biological and biomedical research is controversial-for example, in the comparison of disease risk in different groups or as a means of making use of or controlling for population structure in the mapping of genes to chromosomes. Biogeographical ancestry (BGA) has been recommended as a more accurate and appropriate category. BGA is a product of the collaboration between biological anthropologist Mark Shriver from Pennsylvania State University and molecular biologist Tony Frudakis from the now-defunct biotechnology start-up company DNAPrint genomics, Inc. Shriver and Frudakis portray BGA as a measure of the 'biological', 'genetic', 'natural', and 'objective' components of race and ethnicity, what philosophers of science would call a natural kind. This paper argues that BGA is not a natural kind that escapes social and political connotations of race and ethnicity, as Shriver and Frudakis and other proponents believe, but a construction that is built upon race-as race has been socially constructed in the European scientific and philosophical traditions. More specifically, BGA is not a global category of biological and anthropological classification but a local category shaped by the U.S. context of its production, especially the forensic aim of being able to predict the race or ethnicity of an unknown suspect based on DNA found at the crime scene. Therefore, caution needs to be exercised in the embrace of BGA as an alternative to the use of racial and ethnic categories in biological and biomedical research.

  7. Systematics of axion inflation in Calabi-Yau hypersurfaces

    Science.gov (United States)

    Long, Cody; McAllister, Liam; Stout, John

    2017-02-01

    We initiate a comprehensive survey of axion inflation in compactifications of type IIB string theory on Calabi-Yau hypersurfaces in toric varieties. For every threefold with h 1,1 ≤ 4 in the Kreuzer-Skarke database, we compute the metric on Kähler moduli space, as well as the matrix of four-form axion charges of Euclidean D3-branes on rigid divisors. These charges encode the possibility of enlarging the field range via alignment. We then determine an upper bound on the inflationary field range Δ ϕ that results from the leading instanton potential, in the absence of monodromy. The bound on the field range in this ensemble is Δ ϕ ≲ 0 .3 M pl, in a compactification where the smallest curve volume is (2 π)2 α', and we argue that the sigma model expansion is adequately controlled. The largest increase resulting from alignment is a factor ≈ 2 .6. We also examine a set of threefolds with h 1,1 up to 100 and characterize their axion charge matrices. While we find modest alignment in this ensemble, the maximum field range is ultimately suppressed by the volume of the internal space, which typically grows quickly with h 1,1. Furthermore, we find that many toric divisors are rigid — and the corresponding charge matrices are relatively trivial — at large h 1,1. It is therefore challenging to realize alignment via superpotentials generated only by Euclidean D3-branes, without taking into account the effects of flux, D7-branes, and orientifolding.

  8. Team Building

    OpenAIRE

    Galan, Adriana; Scintee, Silvia-Gabriela

    2008-01-01

    Because there are no pure formal or informal organisations in real world, one may conclude that an organisation is a mix of formal and informal groups. Thus, its performance depends on the management ability to recognise the existence of these groups, to transform them from groups into working teams, to motivate and stimulate them to achieve organisation’s goals. We must differentiate the concept of group versus the concept of team. A simple definition of the group can be: two or more persons...

  9. Recombination era magnetic fields from axion dark matter

    CERN Document Server

    Banik, Nilanjan

    2015-01-01

    We introduce a new mechanism for generating magnetic fields in the recombination era. This Harrison-like mechanism utilizes vorticity in baryons that is sourced through the Bose-Einstein condensate of axions via gravitational interactions. The magnetic fields generated are on the galactic scales $\\sim 10\\,{\\rm kpc}$ and have a magnitude of the order of $B\\sim10^{-23}\\,{\\rm G}$ today. The field has a greater magnitude than those generated from other mechanisms relying on second order perturbation theory, and is sufficient to provide a seed for battery mechanisms.

  10. Preheating and Entropy Perturbations in Axion Monodromy Inflation

    CERN Document Server

    ,

    2016-01-01

    We study the preheating of gauge fields in a simple axion monodromy model and compute the induced entropy perturbations and their effect on the curvature fluctuations. We find that the correction to the spectrum of curvature perturbations has a blue spectrum with index $n_s = 5/2$. Hence, these induced modes are harmless for the observed structure of the universe. Since the spectrum is blue, there is the danger of overproduction of primordial black holes. However, we show that the observational constraints are easily satisfied.

  11. Preheating and entropy perturbations in axion monodromy inflation

    Energy Technology Data Exchange (ETDEWEB)

    McDonough, Evan; Moghaddam, Hossein Bazrafshan [Department of Physics, McGill University,Montréal, QC H3A 2T8 (Canada); Brandenberger, Robert H. [Department of Physics, McGill University,Montréal, QC H3A 2T8 (Canada); Institute for Theoretical Studies, ETH Zürich,CH-8092 Zürich (Switzerland)

    2016-05-04

    We study the preheating of gauge fields in a simple axion monodromy model and compute the induced entropy perturbations and their effect on the curvature fluctuations. We find that the correction to the spectrum of curvature perturbations has a blue spectrum with index n{sub s}=5/2. Hence, these induced modes are harmless for the observed structure of the universe. Since the spectrum is blue, there is the danger of overproduction of primordial black holes. However, we show that the observational constraints are easily satisfied.

  12. Recombination era magnetic fields from axion dark matter

    Science.gov (United States)

    Banik, Nilanjan; Christopherson, Adam J.

    2016-02-01

    We introduce a new mechanism for generating magnetic fields in the recombination era. This Harrison-like mechanism utilizes vorticity in baryons that is sourced through the Bose-Einstein condensate of axions via gravitational interactions. The magnetic fields generated are on galactic scales ˜10 kpc and have a magnitude of the order of B ˜1 0-23G today. The field has a greater magnitude than those generated from other mechanisms relying on second-order perturbation theory, and is sufficient to provide a seed for battery mechanisms.

  13. Towards discrimination between galactic and intergalactic axion-photon mixing

    CERN Document Server

    Troitsky, Sergey

    2015-01-01

    There exists a growing evidence for anomalous transparency of the Universe for energetic gamma rays. Popular explanations include conversion of photons into hypothetical axion-like particles (ALPs) and back in astrophysical magnetic fields. Two distinctive scenarios of this conversion have been put forward: either it happens in the (host galaxy of the) gamma-ray source and in the Milky Way, or the photon-ALP oscillations take place in the intergalactic magnetic fields all along the way between the source and the observer. These two mechanisms imply different ALP parameters. We discuss approaches to distinguish between the two and present some indications in favour of the galactic scenario.

  14. HFSS Simulation on Cavity Coupling for Axion Detecting Experiment

    CERN Document Server

    Yeo, Beomki

    2015-01-01

    In the resonant cavity experiment, it is vital maximize signal power at detector with the minimized reflection from source. Return loss is minimized when the impedance of source and cavity are matched to each other and this is called impedance matching. Establishing tunable antenna on source is required to get a impedance matching. Geometry and position of antenna is varied depending on the electromagnetic eld of cavity. This research is dedicated to simulation to nd such a proper design of coupling antenna, especially for axion dark matter detecting experiment. HFSS solver was used for the simulation.

  15. A New Flavor of Searches for Axion-Like Particles

    CERN Document Server

    Izaguirre, Eder; Shuve, Brian

    2016-01-01

    We propose new searches for axion-like particles (ALPs) produced in flavor-changing neutral current (FCNC) processes. This proposal exploits the often-overlooked coupling of ALPs to W bosons, leading to FCNC production of ALPs even in the absence of a direct coupling to fermions. Our proposed searches for resonant ALP production in decays such as $B\\rightarrow K^{(*)}a,\\,a\\rightarrow \\gamma\\gamma$ and $K\\rightarrow \\pi a, \\,a\\rightarrow \\gamma\\gamma$ could greatly improve upon the current sensitivity to ALP couplings to Standard Model particles. We also determine analogous constraints and discovery prospects for invisibly decaying ALPs.

  16. Geroch-Kinnersley-Chitre group for Dilaton-Axion Gravity

    CERN Document Server

    Galtsov, D V

    1996-01-01

    Kinnersley--type representation is constructed for the four--dimensional Einstein--Maxwell--dilaton--axion system restricted to space--times possessing two non--null commuting Killing symmetries. New representation essentially uses the matrix--valued $SL(2,R)$ formulation and effectively reduces the construction of the Geroch group to the corresponding problem for the vacuum Einstein equations. An infinite hierarchy of potentials is introduced in terms of $2\\times 2$ real symmetric matrices generalizing the scalar hierarchy of Kinnersley--Chitre known for the vacuum Einstein equations.

  17. White dwarfs as physics laboratories: the case of axions

    CERN Document Server

    Isern, J; Catalan, S; Corsico, A; Garcia-Berro, E; Salaris, M; Torres, S

    2012-01-01

    White dwarfs are almost completely degenerate objects that cannot obtain energy from thermonuclear sources, so their evolution is just a gravothermal cooling process. Recent improvements in the accuracy and precision of the luminosity function and in pulsational data of variable white dwarfs suggest that they are cooling faster than expected from conventional theory. In this contribution we show that the inclusion of an additional cooling term due to axions able to interact with electrons with a coupling constant g_ae ~(2-7)x10^{-13} allows to fit better the observations.

  18. Wilson fermions and axion electrodynamics in optical lattices.

    Science.gov (United States)

    Bermudez, A; Mazza, L; Rizzi, M; Goldman, N; Lewenstein, M; Martin-Delgado, M A

    2010-11-05

    We show that ultracold Fermi gases in optical superlattices can be used as quantum simulators of relativistic lattice fermions in 3+1 dimensions. By exploiting laser-assisted tunneling, we find an analogue of the so-called naive Dirac fermions, and thus provide a realization of the fermion doubling problem. Moreover, we show how to implement Wilson fermions, and discuss how their mass can be inverted by tuning the laser intensities. In this regime, our atomic gas corresponds to a phase of matter where Maxwell electrodynamics is replaced by axion electrodynamics: a 3D topological insulator.

  19. Improved constraints on an axion-mediated force.

    Science.gov (United States)

    Hoedl, S A; Fleischer, F; Adelberger, E G; Heckel, B R

    2011-01-28

    Low mass pseudoscalars, such as the axion, can mediate macroscopic parity and time-reversal symmetry-violating forces. We searched for such a force between polarized electrons and unpolarized atoms using a novel, magnetically unshielded torsion pendulum. We improved the laboratory bounds on this force by more than 10 orders of magnitude for pseudoscalars heavier than 1 meV and have constrained this force over a broad range of astrophysically interesting masses (10  μeV to 10 meV).

  20. A Torsion-Balance Search for Axion-Like Particles

    Science.gov (United States)

    Fleischer, Frank; Hoedl, Seth; Adelberger, Eric; Heckel, Blayne; Hoyle, C. D.; Shook, David; Swanson, Erik

    2012-03-01

    Axion-like particles can mediate macroscopic parity and time-reversal symmetry violating forces. We will present a search for such a force between polarized electrons and unpolarized atoms using a novel torsion pendulum operating in the unshielded magnetic field of an electromagnet. Laboratory bounds on this force were improved by more than 10 orders of magnitude for pseudoscalars heavier than 1,, and constraints on this force were established over a broad range of astrophysically interesting masses from 10,eV to 10,. Plans for a next generation of this experiment will be discussed.

  1. Improved Constraints on an Axion-Mediated Force

    Science.gov (United States)

    Hoedl, S. A.; Fleischer, F.; Adelberger, E. G.; Heckel, B. R.

    2011-01-01

    Low mass pseudoscalars, such as the axion, can mediate macroscopic parity and time-reversal symmetry-violating forces. We searched for such a force between polarized electrons and unpolarized atoms using a novel, magnetically unshielded torsion pendulum. We improved the laboratory bounds on this force by more than 10 orders of magnitude for pseudoscalars heavier than 1 meV and have constrained this force over a broad range of astrophysically interesting masses (10μeV to 10 meV).

  2. The Quest for an Intermediate-Scale Accidental Axion and Further ALPs

    CERN Document Server

    Dias, A G; Nishi, C C; Ringwald, A; Vaudrevange, P

    2014-01-01

    The recent detection of the cosmic microwave background polarimeter experiment BICEP2 of tensor fluctuations in the B-mode power spectrum basically excludes all plausible axion models where its decay constant is above $10^{13}$ GeV. Moreover, there are strong theoretical, astrophysical, and cosmological motivations for models involving, in addition to the axion, also axion-like particles (ALPs), with decay constants in the intermediate scale range, between $10^9$ GeV and $10^{13}$ GeV. Here, we present a general analysis of models with an axion and further ALPs and derive bounds on the relative size of the axion and ALP photon (and electron) coupling. We discuss what we can learn from measurements of the axion and ALP photon couplings about the fundamental parameters of the underlying ultraviolet completion of the theory. For the latter we consider extensions of the Standard Model in which the axion and the ALP(s) appear as pseudo Nambu-Goldstone bosons from the breaking of global chiral $U(1)$ (Peccei-Quinn ...

  3. Search for Solar Axions with the CCD Detector and X-ray Telescope at CAST Experiment

    CERN Document Server

    Rosu, Madalin Mihai; Zioutas, Konstantin

    2015-06-09

    The CERN Axion Solar Telescope (CAST) is an experiment that uses the world’s highest sensitivity Helioscope to date for solar Axions searches. Axions are weakly interacting pseudoscalar particles proposed to solve the so-called Strong Charge-Parity Problem of the Standard Model. The principle of detection is the inverse Primakoff Effect, which is a mechanism for converting the Axions into easily detectable X-ray photons in a strong transverse magnetic field. The solar Axions are produced due to the Primakoff effect in the hot and dense core of from the coupling of a real and a virtual photon. The solar models predict a peak Axion luminosity at an energy of 3 keV originating mostly from the inner 20% of the solar radius. Thus an intensity peak at an energy of 3 keV is also expected in the case of the X-ray radiation resulting from Axion conversion. CAST uses a high precision movement system for tracking the Sun twice a day with a LHC dipole twin aperture prototype magnet, 9.26 meters long and with a field of...

  4. CAST search for sub-eV mass solar axions with $^{3}$He buffer gas

    CERN Document Server

    Aune, S; Belov, A; Borghi, S; Brauninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Eleftheriadis, C; Elias, N; Ezer, C; Fanourakis, G; Ferrer-Ribas, E; Friedrich, P; Galan, J; Garcia, J A; Gardikiotis, A; Gazis, E N; Geralis, T; Giomataris, I; Gninenko, S; Gomez, H; Gruber, E; Guthorl, T; Hartmann, R; Haug, F; Hasinoff, M D; Hoffmann, D H H; Iguaz, F J; Irastorza, I G; Jacoby, J; Jakovcic, K; Karuza, M; Konigsmann, K; Kotthaus, R; Krcmar, M; Kuster, M; Lakic, B; Laurent, J M; Liolios, A; Ljubicic, A; Lozza, V; Lutz, G; Luzon, G; Morales, J; Niinikoski, T; Nordt, A; Papaevangelou, T; Pivovaroff, M J; Raffelt, G; Rashba, T; Riege, H; Rodriguez, A; Rosu, M; Ruz, J; Savvidis, I; Silva, P S; Solanki, S.K; Stewart, L; Tomas, A; Tsagri, M; van Bibber, K; Vafeiadis, T; Villar, J A; Vogel, J K; Yildiz, S C; Zioutas, K

    2011-01-01

    The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using 3He as a buffer gas. At T=1.8 K this allows for larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with 4He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV < m_a < 0.64 eV. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 2.3 x 10^{-10} GeV^{-1} at 95% CL, the exact value depending on the pressure setting. KSVZ axions are excluded at the upper end of our mass range, the first time ever for any solar axion search. In future we will extend our search to m_a < 1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.

  5. Revisiting the axion bounds from the Galactic white dwarf luminosity function

    CERN Document Server

    Bertolami, Marcelo M Miller; Althaus, Leandro G; Isern, Jordi

    2014-01-01

    It has been shown that the shape of the luminosity function of white dwarfs (WDLF) is a powerful tool to check for the possible existence of DFSZ-axions, a proposed but not yet detected type of weakly interacting particles. With the aim of deriving new constraints on the axion mass, we compute in this paper new theoretical WDLFs on the basis of WD evolving models that incorporate for the feedback of axions on the thermal structure of the white dwarf. We find that the impact of the axion emission into the neutrino emission can not be neglected at high luminosities ($M_{\\rm Bol}\\lesssim 8$) and that the axion emission needs to be incorporated self-consistently into the evolution of the white dwarfs when dealing with axion masses larger than $m_a\\cos^2\\beta\\gtrsim 5$ meV (i.e. axion-electron coupling constant $g_{ae}\\gtrsim 1.4\\times 10^{-13}$). We went beyond previous works by including 5 different derivations of the WDLF in our analysis. Then we have performed $\\chi^2$-tests to have a quantitative measure of t...

  6. Testing the race inequality

    DEFF Research Database (Denmark)

    Gondan, Matthias; Heckel, A.

    2008-01-01

    In speeded response tasks with redundant signals, parallel processing of the redundant signals is generally tested using the so-called race inequality. The race inequality states that the distribution of fast responses for a redundant stimulus never exceeds the summed distributions of fast...... responses for the single stimuli. It has been pointed out that fast guesses (e.g. anticipatory responses) interfere with this test, and a correction procedure ('kill-the-twin' procedure) has been suggested. In this note we formally derive this procedure and extend it to the case in which redundant stimuli...... are presented with onset asynchrony. We demonstrate how the kill-the-twin procedure is used in a statistical test of the race model prediction....

  7. The quest for an intermediate-scale accidental axion and further ALPs

    Energy Technology Data Exchange (ETDEWEB)

    Dias, A.G.; Nishi, C.C. [Univ. Federal do ABC - UFABC, Sao Paulo (Brazil); Machado, A.C.B. [Teorica-Univ. Estadual Paulista, Sao Paulo (Brazil). Instituto de Fisica; Ringwald, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Vaudrevange, P. [Technische Univ. Muenchen, Garching (Germany). Excellence Cluster Universe

    2014-03-15

    The recent detection of the cosmic microwave background polarimeter experiment BICEP2 of tensor fluctuations in the B-mode power spectrum basically excludes all plausible axion models where its decay constant is above 10{sup 13} GeV. Moreover, there are strong theoretical, astrophysical, and cosmological motivations for models involving, in addition to the axion, also axion-like particles (ALPs), with decay constants in the intermediate scale range, between 10{sup 9} GeV and 10{sup 13} GeV. Here, we present a general analysis of models with an axion and further ALPs and derive bounds on the relative size of the axion and ALP photon (and electron) coupling. We discuss what we can learn from measurements of the axion and ALP photon couplings about the fundamental parameters of the underlying ultraviolet completion of the theory. For the latter we consider extensions of the Standard Model in which the axion and the ALP(s) appear as pseudo Nambu-Goldstone bosons from the breaking of global chiral U(1) (Peccei-Quinn (PQ)) symmetries, occuring accidentally as low energy remnants from exact discrete symmetries. In such models, the axion and the further ALP are protected from disastrous explicit symmetry breaking effects due to Planck-scale suppressed operators. The scenarios considered exploit heavy right handed neutrinos getting their mass via PQ symmetry breaking and thus explain the small mass of the active neutrinos via a seesaw relation between the electroweak and an intermediate PQ symmetry breaking scale. We show some models that can accommodate simultaneously an axion dark matter candidate, an ALP explaining the anomalous transparency of the universe for γ-rays, and an ALP explaining the recently reported 3.55 keV gamma line from galaxies and clusters of galaxies, if the respective decay constants are of intermediate scale.

  8. TEAM ORGANISERING

    DEFF Research Database (Denmark)

    Levisen, Vinie; Haugaard, Lena

    2004-01-01

    organisation som denne? Når teams i samtiden anses for at være en organisationsform, der fremmer organisatorisk læring, beror det på, at teamet antages at udgøre et ikke-hierarkisk arbejdsfællesskab, hvor erfaringer udveksles og problemer løses. Teamorganisering kan imidlertid udformes på mange forskellige...

  9. Axion Dark Matter and Planck favor non-minimal couplings to gravity

    CERN Document Server

    Folkerts, Sarah; Redondo, Javier

    2013-01-01

    Constraints on inflationary scenarios and isocurvature perturbations have excluded the simplest and most generic models of dark matter based on QCD axions. Considering non-minimal kinetic couplings of scalar fields to gravity substantially changes this picture. The axion can account for the observed dark matter density in the anthropic window avoiding an overproduction of isocurvature fluctuations. Finally, we show that assuming the same non-minimal kinetic coupling to the axion (dark matter) and to the standard model Higgs boson (inflaton) provides a minimal picture of early time cosmology.

  10. Axion dark matter and Planck favor non-minimal couplings to gravity

    Energy Technology Data Exchange (ETDEWEB)

    Folkerts, Sarah, E-mail: sarah.folkerts@lmu.de [Arnold Sommerfeld Center, Ludwig-Maximilians-University, Theresienstr. 37, 80333 München (Germany); Germani, Cristiano, E-mail: cristiano.germani@lmu.de [Arnold Sommerfeld Center, Ludwig-Maximilians-University, Theresienstr. 37, 80333 München (Germany); Redondo, Javier, E-mail: javier.redondo@lmu.de [Arnold Sommerfeld Center, Ludwig-Maximilians-University, Theresienstr. 37, 80333 München (Germany); Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, 80805 München (Germany)

    2014-01-20

    Constraints on inflationary scenarios and isocurvature perturbations have excluded the simplest and most generic models of dark matter based on QCD axions. Considering non-minimal kinetic couplings of scalar fields to gravity substantially changes this picture. The axion can account for the observed dark matter density avoiding the overproduction of isocurvature fluctuations. Finally, we show that assuming the same non-minimal kinetic coupling to the axion (dark matter) and to the standard model Higgs boson (inflaton) provides a minimal picture of early time cosmology.

  11. The Einstein-Maxwell-aether-axion theory: Dynamo-optical anomaly in the electromagnetic response

    CERN Document Server

    Alpin, Timur Yu

    2015-01-01

    We consider a pp-wave symmetric model in the framework of the Einstein-Maxwell-aether-axion theory. Exact solutions to the equations of axion electrodynamics are obtained for the model, in which pseudoscalar, electric and magnetic fields were constant before the arrival of a gravitational pp-wave. We show that dynamo-optical interactions, i.e., couplings of electromagnetic field to a dynamic unit vector field, attributed to the velocity of a cosmic substratum (aether, vacuum, dark fluid...), provide the response of axionically active electrodynamic system to display anomalous behavior.

  12. Designing, building, testing and racing a low-cost fuel cell range extender for a motorsport application

    Science.gov (United States)

    Cordner, M.; Matian, M.; Offer, G. J.; Hanten, T.; Spofforth-Jones, E.; Tippetts, S.; Agrawal, A.; Bannar-Martin, L.; Harito, L.; Johnson, A.; Clague, R.; Marquis, F.; Heyes, A.; Hardalupas, Y.; Brandon, N. P.

    Imperial Racing Green is an undergraduate teaching project at Imperial College London. Undergraduate engineers have designed, built and raced hydrogen fuel cell hybrid vehicles in the Formula Zero and Formula Student race series. Imperial Racing Green has collaborated with its fuel cell partners to develop a 13 kW automotive polymer electrolyte membrane fuel cell (PEMFC) system. A team of undergraduate engineers were given a relatively modest budget and less than 8 months to design and assemble an operational high-power PEMFC system. The fuel cell system was designed to provide the average power required by the team's 2011 Formula Student entry. This paper presents the team's experience of developing and testing an automotive fuel cell system for a race application and plans for its future development and integration onto the vehicle.

  13. Stueckelberg Axions and Anomalous Abelian Extensions of the Standard Model

    CERN Document Server

    Morelli, Simone

    2009-01-01

    This thesis work analyzes basic field theoretical aspects of a class of models motivated by orientifold vacua of string theory and some of their phenomenological applications at the Large Hadron Collider. They extend the gauge structure of the Standard Model by anomalous extra U(1) symmetries, which involve Stuckelberg axions for anomaly cancellation and are accompanied by Chern-Simons interactions. In particular, these effective actions are characterized by a physical pseudoscalar (the axi-Higgs) in the CP-odd spectrum, which has the properties of a generalized Peccei-Quinn axion, with independent mass and couplings to the gauge fields. Amplitudes mediated by anomalous gauge interactions are studied at the new collider in some specific channels such as Drell-Yan and double prompt-photon and shown to be small. Finally, we address the problem of the relation between the Green-Schwarz and the Wess-Zumino mechanism(s) for anomaly cancellations in effective lagrangeans involving anomalous gauge interactions, with...

  14. New model of axion monodromy inflation and its cosmological implications

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yi-Fu [CAS Key Laboratory for Researches in Galaxies and Cosmology,Department of Astronomy, University of Science and Technology of China,Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Department of Physics, McGill University,Montréal, QC, H3A 2T8 (Canada); Chen, Fang [Kavli Institute for Theoretical Physics, University of California,Santa Barbara, California 93106 (United States); Ferreira, Elisa G.M.; Quintin, Jerome [Department of Physics, McGill University,Montréal, QC, H3A 2T8 (Canada)

    2016-06-10

    We propose a new realization of axion monodromy inflation in which axion monodromy arises from torsional cycles in a type IIB compactification. A class of monomial potentials is obtained with specific values for the power index. Moreover, the inflaton mass changes profile due to the couplings between various fields after compactification. Consequently, the potential obtains a step-like profile at some critical scale. We study the cosmological implications of one concrete realization of this model. At the background level, it realizes a sufficiently long inflationary stage, which allows for the violation of the slow-roll conditions for a short period of time when the inflaton is close to the critical scale. Accordingly, the Hubble horizon is perturbed and affects the dynamics of primordial cosmological perturbations. In particular, we analyze the angular power spectrum of B-mode polarization and find a boost on very large scales. We also find that the amplitude of scalar perturbations is suppressed near the critical scale. Thus our model provides an interpretation for the low-ℓ suppression of temperature anisotropies in the CMB power spectrum. We examine these effects and confront the model to observations.

  15. Stationary BPS solutions to dilaton-axion gravity

    CERN Document Server

    Clément, G

    1996-01-01

    Stationary four-dimensional BPS solutions to gravity coupled bosonic theories admitting a three--dimensional sigma--model representation on coset spaces are interpreted as null geodesics of the target manifold equipped with a certain number of harmonic maps. For asymptotically flat (or Taub--NUT) space--times such geodesics can be directly parametrized in terms of charges saturating the Bogomol'nyi--Gibbons--Hull bound, and classified according to the structure of related coset matrices. We investigate in detail the ``dilaton--axion gravity'' with one vector field, and show that in the space of BPS solutions an SO(1,2) \\times SO(2) classical symmetry is acting. Within the present formalism the most general multicenter (IWP/Taub--NUT dyon) solutions are derived in a simple way. We also discover a large new class of asymptotically flat solutions for which the dilaton and axion charges are constrained only by the BPS bound. The string metrics for these solutions are generically regular. Both the IWP class and th...

  16. Hypercharge Axion and the Diphoton $750$ GeV Resonance

    CERN Document Server

    Ben-Dayan, Ido

    2016-01-01

    The CMS and ATLAS reports on a possible excess of diphoton events at $750$ GeV are the cause of great excitement and hope. We show that a pseudoscalar axion coupled to the topological density of hypercharge, suggested in the past by Brustein and Oaknin as a candidate for inducing baryogenesis, can explain the signal in the diphoton channel. The hypercharge axion (HCA) can also decay to $Z\\gamma$ and $ZZ$. The expected number of events in these channels is too small to have been detected, but such decays should be observed in the future. The HCA can be produced via vector boson fusion (VBF) or via associated production (AP). The latter should be manifested by a characteristic decay to 3 photons which should be observed soon. We adapt the previous analysis of possible detection of the HCA at the LHC by Brustein and Oaknin and by Elfgren to the case that the mass of the HCA is 750 GeV and find the expected cross section and decay width in terms of the HCA coupling. We find that the expected cross-section fits we...

  17. Roulette Inflation with K\\"ahler Moduli and their Axions

    CERN Document Server

    Bond, J R; Prokushkin, S F; Vaudrevange, P M

    2006-01-01

    We study 2-field inflation models based on the ``large-volume'' flux compactification of type IIB string theory. The role of the inflaton is played by a K\\"ahler modulus \\tau corresponding to a 4-cycle volume and its axionic partner \\theta. The freedom associated with the choice of Calabi Yau manifold and the non-perturbative effects defining the potential V(\\tau, \\theta) and kinetic parameters of the moduli bring an unavoidable statistical element to theory prior probabilities within the low energy landscape. The further randomness of (\\tau, \\theta) initial conditions allows for a large ensemble of trajectories. Features in the ensemble of histories include ``roulette tractories'', with long-lasting inflations in the direction of the rolling axion, enhanced in number of e-foldings over those restricted to lie in the \\tau-trough. Asymptotic flatness of the potential makes possible an eternal stochastic self-reproducing inflation. A wide variety of potentials and inflaton trajectories agree with the cosmic mic...

  18. Axion Monodromy Inflation with Warped KK-Modes

    CERN Document Server

    Hebecker, Arthur; Westphal, Alexander; Witkowski, Lukas T

    2015-01-01

    We present a particularly simple model of axion monodromy inflation: Our axion is the lowest-lying KK-mode of the RR-2-form-potential $C_2$ in the standard Klebanov-Strassler throat. One can think of this inflaton candidate as being defined by the integral of $C_2$ over the $S^2$ cycle of the throat. It obtains an exponentially small mass from the IR-region in which the $S^2$ shrinks to zero size. Crucially, the $S^2$ cycle has to be shared between two throats, such that the second locus where the $S^2$ shrinks is also in a warped region. Well-known problems like the potentially dangerous back-reaction of brane/antibrane pairs and explicit supersymmetry breaking are not present in our scenario. The inflaton back-reaction on the geometry turns out to be controlled by the string coupling $g_s$. We hope that our setting is simple enough for many critical consistency issues of large-field inflation in string theory to be addressed at a quantitative level.

  19. Axion monodromy inflation with warped KK-modes

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    Arthur Hebecker

    2016-03-01

    Full Text Available We present a particularly simple model of axion monodromy inflation: Our axion is the lowest-lying KK-mode of the RR-2-form-potential C2 in the standard Klebanov–Strassler throat. One can think of this inflaton candidate as being defined by the integral of C2 over the S2 cycle of the throat. It obtains an exponentially small mass from the IR-region in which the S2 shrinks to zero size. Crucially, the S2 cycle has to be shared between two throats, such that the second locus where the S2 shrinks is also in a warped region. Well-known problems like the potentially dangerous back-reaction of brane/antibrane pairs and explicit supersymmetry breaking are not present in our scenario. The inflaton back-reaction on the geometry turns out to be controlled by the string coupling gs. We hope that our setting is simple enough for many critical consistency issues of large-field inflation in string theory to be addressed at a quantitative level.

  20. Axion monodromy inflation with warped KK-modes

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    Hebecker, Arthur; Moritz, Jakob; Witkowski, Lukas T. [Heidelberg Univ. (Germany). Inst. for Theoretical Physics; Westphal, Alexander [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-12-15

    We present a particularly simple model of axion monodromy inflation: Our axion is the lowest-lying KK-mode of the RR-2-form-potential C{sub 2} in the standard Klebanov-Strassler throat. One can think of this inflaton candidate as being defined by the integral of C{sub 2} over the S{sup 2} cycle of the throat. It obtains an exponentially small mass from the IR-region in which the S{sup 2} shrinks to zero size. Crucially, the S{sup 2} cycle has to be shared between two throats, such that the second locus where the S{sup 2} shrinks is also in a warped region. Well-known problems like the potentially dangerous back-reaction of brane/antibrane pairs and explicit supersymmetry breaking are not present in our scenario. The inflaton back-reaction on the geometry turns out to be controlled by the string coupling g{sub s}. We hope that our setting is simple enough for many critical consistency issues of large-field inflation in string theory to be addressed at a quantitative level.