China's Shineray Racing Team Hits International Circuit
Institute of Scientific and Technical Information of China (English)
无
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.
International Nuclear Information System (INIS)
The Peccei-Quinn symmetry is a possible solution to the strong C.P. violation problem resulting from instantons contributions. It is the objective of this dissertation to study models which incorporate the Paccei-Ouinn symmetry as well as its consequences, for instance, the exiatence of a Goldstone pseudoboson named axion and the appearence of topologically satble structures generated at the spontaneous breakdown of the Peccei-Quinn symmetry. We also study the interchanged between axion models and Cosmology, particularly the influence of axions on the process of galsxy formation. (author)
International Nuclear Information System (INIS)
Axion physics is briefly reviewed, including the constraints on the axion decay constant from laboratory experiments, from stellar evolution and from the cosmological axion energy density. Experiments to detect axions emitted by the sun or axions floating about in the halo of our galaxy are discussed. 19 references
The Axion Dark Matter Experiment: Big Science with a (relatively) Small Team
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.
Energy Technology Data Exchange (ETDEWEB)
Hayashi, Y. [Aoyama Gakuin University, Tokyo (Japan)
1994-09-20
This paper introduces how the Aoyama Gakuin University team competed in the World Solar Car Rally race held at Ogata Village in Akita Prefecture, Japan, in the summer of 1994. The race was formed with solar cars mounting a solar panel with the maximum area of 8 m{sup 2} and batteries with a total output of 3 kWh to compete how many rounds the cars can run around a course of 31 km during three days (25 hours in total). The solar car used by the University team had consumed power of about 600 W at a speed of 40 km/h, with the solar panel generating power of 800 Wp. The first day morning was sunny making possible to set the average speed to 45 km/h (power generation of 500 W or more), but the weather worsened in the afternoon compelling the car to change the speed to 30 km/h (power generation of 200 W). The power generated on the second day, which was cloudy all day, stayed at 250 W at the maximum, hence the speed was kept at 30 km/h to suppress the power consumption. On the sunny third day, the team drove the car worrying about the remaining battery capacity, and succeeded the drive of 23 rounds in total, winning the second prize among 30 cars participated in the junior class race.
Montero, Miguel; Valenzuela, Irene
2015-01-01
We discuss quantum gravitational effects in Einstein theory coupled to periodic axion scalars to analyze the viability of several proposals to achieve superplanckian axion periods (aka decay constants) and their possible application to large field inflation models. The effects we study correspond to the nucleation of euclidean gravitational instantons charged under the axion, and our results are essentially compatible with (but independent of) the Weak Gravity Conjecture, as follows: Single axion theories with superplanckian periods contain gravitational instantons inducing sizable higher harmonics in the axion potential, which spoil superplanckian inflaton field range. A similar result holds for multi-axion models with lattice alignment (like the Kim-Nilles-Peloso model). Finally, theories with $N$ axions can still achieve a moderately superplanckian periodicity (by a $\\sqrt{N}$ factor) with no higher harmonics in the axion potential. The Weak Gravity Conjecture fails to hold in this case due to the absence ...
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
Ototoxic occupational exposures for a stock car racing team: I. Noise surveys.
Van Campen, Luann E; Morata, Thais; Kardous, Chucri A; Gwin, Kristin; Wallingford, Kenneth M; Dallaire, Jacques; Alvarez, Frank J
2005-08-01
The National Institute for Occupational Safety and Health (NIOSH) surveyed noise exposure for a professional stock car team at their race shop and during two races at one racetrack. At the team's shop, area sound pressure levels (SPLs) were measured for various work tasks. Equivalent levels (Leqs) ranged from 58 to 104 decibels, A-weighted (dBA). Personal noise dosimetry was conducted for at least one employee for each job description in race car assembly (n = 9). The Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) of 90 dBA for an 8-hour, 5-dB exchange rate time-weighted average (TWA) was never exceeded, but in two instances values exceeded OSHA's action level of 85 dBA for hearing conservation implementation. The NIOSH recommended exposure limit (REL) of 85 dBA for a 3-dB exchange rate Leq was exceeded for five of the measured jobs. During the races, SPLs averaged above 100 dBA in the pit area where cars undergo adjustments/refueling, both before and during the race. Peak levels reached 140 dB SPL. NIOSH REL was exceeded for every personal noise dosimetry measurement. Recommendations for hearing protection and communication are presented. PMID:16080260
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...
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_{\
Ringwald, A.
2012-01-01
In this master's thesis we study the cosmological consequences of the new scalar field, the axion, that appears in the U(1)_PQ extension of the standard model of particle physics. We start by presenting some essential fragments of the standard model of Big Bang cosmology, that are needed when we describe the evolution of the axion field in the early Universe. We also review the basics of phase transitions in the early Universe, and go through the creation and evolution of the topological defe...
International Nuclear Information System (INIS)
The possibility of axion production in the Earth's interior due to natural radioactive decay is considered. Axions, or axion-like particles, could be created in nuclear disintegrations and deexitations of natural radionuclides present in the Earth's crust and mantle, as well as due to photon to axion conversion of the emitted gamma rays via the Primakoff effect. The estimated geo-axion production rates and fluxes on the Earth's surface are given along with the axion coupling to ordinary matter in the frame of the simple axion models as well as for axion-like particles with stronger couplings
Energy Technology Data Exchange (ETDEWEB)
Aurilia, A. (Dept. of Physics, California State Polytechnic Univ., Pomona, CA (United States)); Spallucci, E. (Dipt. di Fisica Teorica, Univ. Trieste (Italy) INFN, Sezione Trieste (Italy))
1992-05-21
A metal ring removed from a soap-water solution encloses a film of soap which can be mathematically described as a minimal surface having the ring as its only boundary. This is known to everybody. In this letter we suggest a relativistic extension of the above fluidodynamic system where the soap film is replaced by a Kalb-Ramand gauge potential B{sub {mu}{nu}}(x) and the ring by a closed string. The interaction between the B{sub {mu}{nu}} field and the string current excites a new configuration of the system consisting of a relativistic membrane bounded by the string. We call such a classical solution of the equation of motion an axionic membrane. As a dynamical system, the axionic membrane admits a Hamilton-Jacobi formulation which is an extension of the HJ theory of electromagnetic strings. (orig.).
Axions at the International Axion Observatory
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.
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.
Design, analysis and simulation of the suspension system in the FS team UiS race car
Brevik, Vegard
2013-01-01
This master thesis concerns the design and analysis of the suspension for the Formula Student Team UiS racing car for the Formula Student 2013 student competition. To analyze how parameters such as track width, wheelbase, weight distribution, CoG height and total weight affected the overall performance a virtual racetrack was constructed. Calculations were then done to find the cars lap time as the various parameters were altered. Results showed that reduced weight and CoG height and in...
CERN. Geneva
2005-01-01
Outline of the lecture: Constraints from laboratory searches and astrophysics, axion cosmology, the cavity detector of dark matter axions, solar axion searches, laser experiments, a telescope search, macroscopic forces mediated by axions.
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...
Axions - Motivation, limits and searches
Raffelt, Georg G.
2006-01-01
The axion solution of the strong CP problem provides a number of possible windows to physics beyond the standard model, notably in the form of searches for solar axions and for galactic axion dark matter, but in a broader context also inspires searches for axion-like particles in pure laboratory experiments. We briefly review the motivation for axions, astrophysical limits, their possible cosmological role, and current searches for axions and axion-like particles.
International Nuclear Information System (INIS)
The existence of axions, proposed as very light neutral pseudoscalar bosons, would solve the strong CP problem in the QCD. Axions also arise in supersymmetric and superstring theories and are candidates for dark matter in the universe. Cosmological and astrophysical arguments restrict the masses (ma) of invisible axions to rather narrow 10-5 eV → ma → 10-22 eV range, but with large uncertainties on either side. The KSVZ or hadronic axion is one version of invisible axions, which predicts small coupling of axions to electrons. Models of hadronic axions with E/N ≅ 2 allow for a near or complete cancellation of the axion-photon coupling constant. In this case there is no stellar-evolution limits on ma and for hadronic axions there exists a small window 10 eV ≤ ma ≤ 40 eV between supernova cooling and axion burst arguments. So far the best and only discussed candidate for hot dark matter has been the massive neutrino with a mass of a few eV. Because the Super-Kamiokande experiment suggests the tau neutrino mass of only 0.03-0.1 eV, the hadronic axion in the so-called hadronic axion window could be a good candidate for a cosmological hot dark matter within the mixed dark matter scenario. To verify this window one can search for axions by appealing only to their coupling to nucleons. The most promising methods are the observation of an axion burst from a future supernova and the resonant absorption of almost monochromatic solar axions. We have performed the first experiment along this new line of solar axion investigations. Using a small target of 0.03 g of 57Fe we have made a search for 14.4 keV gamma rays induced by resonant absorption of almost monochromatic solar axions. These Doppler broadened axions could be emitted from the Sun, in M1 transition between the first, thermally excited state and the ground state of 57Fe. An upper limit on hadronic axion mass of 745 eV is obtained at the 95 % confidence level. Search for solar axions is beginning to become
Energy Technology Data Exchange (ETDEWEB)
Nowakowski, Daniel; Kuster, Markus; Meister, Claudia V.; Fuelbert, Florian; Hoffmann, Dieter H.H. [TU Darmstadt (Germany). Institut fuer Kernphysik; Weiss, Achim [Max-Planck-Institut fuer Astrophysik, Garching (Germany)
2010-07-01
An axion helioscope is typically operated to observe the sun as an axion source. Additional pointings at celestial sources, e.g. stars in other galaxies, result in possible detections of axions from distant galactic objects. For the observation of supplementary axion sources we therefore calculate the thereotical axion flux from distant stars by extending axionic flux models for the axion Primakoff effect in the sun to other main sequence stars. The main sequence star models used for our calculations are based on full stellar structure calculations. To deduce the effective axion flux of stellar objects incident on the Earth the All-Sky catalogue was used to obtain the spectral class and distance of the stars treated. Our calculations of the axion flux in the galactic plane show that for a zero age main sequence star an maximum axion flux of {phi}{sub a}=303.43 cm{sup -2}s{sup -1} could be expected. Furthermore we present estimates of axion fluxes from time-evolved stars.
International Nuclear Information System (INIS)
An axion helioscope is typically operated to observe the sun as an axion source. Additional pointings at celestial sources, e.g. stars in other galaxies, result in possible detections of axions from distant galactic objects. For the observation of supplementary axion sources we therefore calculate the thereotical axion flux from distant stars by extending axionic flux models for the axion Primakoff effect in the sun to other main sequence stars. The main sequence star models used for our calculations are based on full stellar structure calculations. To deduce the effective axion flux of stellar objects incident on the Earth the All-Sky catalogue was used to obtain the spectral class and distance of the stars treated. Our calculations of the axion flux in the galactic plane show that for a zero age main sequence star an maximum axion flux of Φa=303.43 cm-2s-1 could be expected. Furthermore we present estimates of axion fluxes from time-evolved stars.
CERN. Geneva
2005-01-01
A summary of the status of axions and axion-like particles will be given. Special attention is devoted to the recent results of the PVLAS collaboration, which are in conflict with CAST data and with astrophysical constraints. Solutions to this puzzle and the implications for new physics are dicussed. The subject of axion-like particles as dark matter will be included in the lecture. Finally some new results on new forces mediated by light scalars are debated.
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.
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.
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...
Axions as Dark Matter Particles
Duffy, Leanne D.; Bibber, Karl van
2009-01-01
We review the current status of axions as dark matter. Motivation, models, constraints and experimental searches are outlined. The axion remains an excellent candidate for the dark matter and future experiments, particularly the Axion Dark Matter eXperiment (ADMX), will cover a large fraction of the axion parameter space.
Stern, I
2014-01-01
Nearly all astrophysical and cosmological data point convincingly to a large component of cold dark matter in the Universe. The axion particle, first theorized as a solution to the strong charge-parity problem of quantum chromodynamics, has been established as a prominent CDM candidate. Cosmic observation and particle physics experiments have bracketed the unknown mass of the axion between approximately a $\\mu$eV and a meV. The Axion Dark Matter eXperiement (ADMX) has successfully completed searches between 1.9 and 3.7 $\\mu$eV down to the KSVZ photon-coupling limit. ADMX and the Axion Dark Matter eXperiement High-Frequency (ADMX-HF) will search for axions at weaker coupling and/or higher frequencies within the next few years. Status of the experiments, current research and development, and projected mass-coupling exclusion limits are presented.
Minowa, M; Akimoto, Y; Ohta, R; Mizumoto, T; Yamamoto, A
2008-01-01
A new search result of the Tokyo axion helioscope is presented. The axion helioscope consists of a dedicated cryogen-free 4T superconducting magnet with an effective length of 2.3 m and PIN photodiodes as x-ray detectors. Solar axions, if exist, would be converted into X-ray photons through the inverse Primakoff process in the magnetic field. Conversion is coherently enhanced even for massive axions by filling the conversion region with helium gas. The present third phase measurement sets a new limit of g_{a\\gamma\\gamma}<(5.6--13.4)\\times10^{-10} GeV^{-1} for the axion mass of 0.84
International Nuclear Information System (INIS)
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 Θ vacuum structure of QCD. However, particle physics gives little guidance as to the axion mass; a priori, the plausible values span the range: 10/sup /minus/12/ eV /approx lt/ m/sub a/ /approx lt/ 106 eV, some 18 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 producing 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/sup /minus/6/ eV /approx lt/ m/sub a/ /approx lt/ 10/sup /minus/3/ eV and 1 eV /approx lt/ m/sub a/ /approx lt/ 5 eV (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. 58 refs., 6 figs., 1 tab
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...
Energy Technology Data Exchange (ETDEWEB)
Turner, M.S.
1989-04-01
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/sup /minus/12/ eV /approx lt/ m/sub a/ /approx lt/ 10/sup 6/ eV, some 18 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 producing 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/sup /minus/6/ eV /approx lt/ m/sub a/ /approx lt/ 10/sup /minus/3/ eV and 1 eV /approx lt/ m/sub a/ /approx lt/ 5 eV (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. 58 refs., 6 figs., 1 tab.
Axion-photon couplings in invisible axion models
International Nuclear Information System (INIS)
We reexamine the axion-photon couplings in various invisible axion models motivated by the recent proposal of using optical interferometry at the ASST facility at the SSCL to search for the axion. We illustrate that the assignment of U(1)PQ charges for the fermion fields plays an important role in determining the couplings. Several simple nonminimal invisible axion models with suppressed and enhanced axion-photon couplings are constructed, respectively. We also discuss the implications of possible new experiments to detect solar axions by conversion to x rays in a static magnetic apparatus tracking the Sun
Towards a realistic axion star
Barranco, J
2008-01-01
In this work we estimate the radius and the mass of a self-gravitating system made of axions. The quantum axion field satisfies the Klein-Gordon equation in a curved space-time and the metric components of this space-time are solutions to the Einstein equations with a source term given by the vacuum expectation value of the energy-momentum operator constructed from the axion field. As a first step towards an axion star we consider the up to the sixth term in the axion potential expansion. We found that axion stars would have masses of the order of asteroids and radius of the order of few centimeters.
International Nuclear Information System (INIS)
The axion particle is the experimental consequence of a particular way to restore P conservation into the QCD theory. The standard axion phenomenology proceeds on a scale given by the electroweak symmetry breaking. Such an axion is ruled out experimentally. Recently, observation of monochromatic peaks in e± production in heavy-ion collisions at GSI Darmstadt has motivated some re-examination of the situation. There appears to be no way to save the notion of an axion at the electroweak scale. Furthermore, experiments with electron beam-dumps have proven, together with g-2 measurements that the GSI effect cannot be explained in terms of a fundamental particle coupled to the e+e- channel
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.
Yang, Qiaoli
2015-01-01
Dark matter particles constitute $23\\%$ of the total energy density of our universe and their exact properties are still unclear besides that they must be very cold and weakly interacting with the standard model particles. Many beyond standard model theories provide proper candidates to serve as the dark matter. The axions were introduced to solve the strong CP problem and later turned out to be a very attractive dark matter candidate. In this paper, we briefly review the physics of axions an...
International Nuclear Information System (INIS)
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.
International Nuclear Information System (INIS)
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 non-perturbative 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.
Axions-motivation, limits and searches
International Nuclear Information System (INIS)
The axion solution of the strong CP problem provides a number of possible windows to physics beyond the standard model, notably in the form of searches for solar axions and for galactic axion dark matter, but in a broader context also inspires searches for axion-like particles in pure laboratory experiments. We briefly review the motivation for axions, astrophysical limits, their possible cosmological role, and current searches for axions and axion-like particles
Anomaly mediation deformed by axion
International Nuclear Information System (INIS)
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
Future axion searches with the International Axion Observatory (IAXO)
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.
Future axion searches with the International Axion Observatory (IAXO)
International Nuclear Information System (INIS)
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
Dark Matter in Axion Landscape
Daido, Ryuji; Kobayashi, Takeshi; 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...
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.
Dark Matter in Axion Landscape
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.
International Nuclear Information System (INIS)
In this talk, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this axionic mirage mediation, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around 1010 GeV to 1012 GeV due to the supersymmetry breaking effects. The problems in the original mirage mediation such as the μ-problem and the moduli problem can be solved simultaneouly. Furthermore, in our model the axino, which is the superpartner of the axion, is the lightest sparticle.
Nakamura, Shuntaro; Yamaguchi, Masahiro
2008-01-01
In this talk, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this \\textit{axionic mirage mediation}, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around $10^{10}$ GeV to $10^{12}$ GeV due to the supersymmetry breaking effects. The problems in the original mirage mediation such as the $\\mu$-problem and the moduli problem can be solved simultaneouly. Furthermore, in our model the axino, which is the superpartner of the axion, is the lightest sparticle.
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.
Cosmological Consequences of String Axions
International Nuclear Information System (INIS)
Axion fluctuations generated during inflation lead to isocurvature and non-Gaussian temperature fluctuations in the cosmic microwave background radiation. Following a previous analysis for the model independent string axion we consider the consequences of a measurement of these fluctuations for two additional string axions. We do so independent of any cosmological assumptions except for the axions being massless during inflation. The first axion has been shown to solve the strong CP problem for most compactifications of the heterotic string while the second axion, which does not solve the strong CP problem, obeys a mass formula which is independent of the axion scale. We find that if gravitational waves interpreted as arising from inflation are observed by the PLANCK polarimetry experiment with a Hubble constant during inflation of Hinf ∼> 1013 GeV the existence of the first axion is ruled out and the second axion cannot obey the scale independent mass formula. In an appendix we quantitatively justify the often held assumption that temperature corrections to the zero temperature QCD axion mass may be ignored for temperatures T ∼QCD
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...
Cosmic Axion Bose-Einstein Condensation
Banik, Nilanjan; Sikivie, Pierre
2015-01-01
QCD axions are a well-motivated candidate for cold dark matter. Cold axions are produced in the early universe by vacuum realignment, axion string decay and axion domain wall decay. We show that cold axions thermalize via their gravitational self-interactions, and form a Bose-Einstein condensate. As a result, axion dark matter behaves differently from the other proposed forms of dark matter. The differences are observable.
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.
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.
International Nuclear Information System (INIS)
We consider the effect of free-streaming axion emission on numerical models for the cooling of the newly born neutron star associated with SN 1987A. We find that for an axion mass of greater than ∼10/sup -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, we have not investigated the possibility that axion trapping (which should occur for masses ≥0.02 eV) sufficiently reduces axion emission so that axion masses greater than ∼2 eV would be consistent with the neutrino observations
International Nuclear Information System (INIS)
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
Axions and the anthropic principle
International Nuclear Information System (INIS)
We consider the possibility that the axion density in the Universe today may be constrained by the anthropic requirement that life should have evolved. If this were the case, the force of the usual cosmological bound on the axion decay constant would be greatly lessened. However, we find no mechanism by which excessive axion energy density could prevent the condensation of matter into potentially life-nurturing structures
Experimental search for solar axions
International Nuclear Information System (INIS)
A new technique has been used to search for solar axions using a single crystal germanium detector. It exploits the coherent conversion of axions into photons when their angle of incidence satisfies a Bragg condition 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 gαγγ -9 GeV-1, independent of axion mass up to ∼ 1 keV
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.
González-Díaz, Pedro F.
2004-01-01
The existence of phantom energy in a universe which evolves to eventually show a big rip doomsday is a possibility which is not excluded by present observational constraints. In this paper it is argued that the field theory associated with a simple quintessence model is compatible with a field definition that is interpretable in terms of a rank-3 axionic tensor field, whenever we consider a perfect-fluid equation of state that corresponds to the phantom energy regime. Explicit expressions for...
Magnetogenesis from axion inflation
Adshead, Peter; Scully, Timothy R; Sfakianakis, Evangelos I
2016-01-01
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 $B_{\\rm eff} \\gtrsim 10^{-16}\\, G$. This result is insensitive to the exact value of the coupling, as long ...
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
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
Level Crossing between QCD Axion and Axion-Like Particle
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.
Axion experiment makes its debut
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)
Electromagnetic detector for relic axions
International Nuclear Information System (INIS)
Axions are particles of small mass postulated to explain CP conservation in strong interactions. The predicted properties of axions provide an explanation for the early clustering of matter into galaxies, the mass in galactic halos, and the missing mass sufficient to close the universe. The interaction of axions with ordinary matter would be extremely weak, but axions should be detectable, because in a strong magnetic field relic axions of mass m/sub a/ would convert into microwave photons with frequency f=m/sub a/c2/h. Predictions for the frequency range from 3 and 24 GHz for relic axions which provide mass density sufficient to close the universe. We propose a laboratory search for relic axions. A specific experimental apparatus is described and system performance is estimated to illustrate the design principles. The microwave signal from axion conversion is produced in a 30 liter microwave cavity which contains dielectric phase shifting plates to give a quality factor (Q) greater than 106, and to provide the correct phasing of the microwave electric field throughout the cavity. The cavity is placed in an 8 Tesla superconducting magnet, and the signal is measured with a conventional microwave receiver employing a GaAs FET rf amplifier or Schottky diode mixer. The cavity, magnet and rf amplifier/mixer will operate at 40K, with noise temperature between 200K and 2000K. The system is equally effective in principle at all frequencies between 1 GHz and 100 GHz at which microwave receivers are available. The corresponding range of axion mass which can be covered is 4x10-6 eV to 4x10-4 eV. A search can be carried out over an octave of frequency in an observation time of three months with sufficient sensitivity to detect axions if they make up the galactic halo
Axion Dark Matter Detection using Atomic Transitions
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.
Cosmological Constant and Axions in String Theory
Energy Technology Data Exchange (ETDEWEB)
Svrcek, Peter; /Stanford U., Phys. Dept. /SLAC
2006-08-18
String theory axions appear to be promising candidates for explaining cosmological constant via quintessence. In this paper, we study conditions on the string compactifications under which axion quintessence can happen. For sufficiently large number of axions, cosmological constant can be accounted for as the potential energy of axions that have not yet relaxed to their minima. In compactifications that incorporate unified models of particle physics, the height of the axion potential can naturally fall close to the observed value of cosmological constant.
International Nuclear Information System (INIS)
Although mirage mediation is one of the most plausible mediation mechanisms of supersymmetry breaking, it suffers from two crucial problems. One is the μ/Bμ problem, and the second is the cosmological one. The former stems from the fact that the B parameter tends to be comparable with the gravitino mass, which is 2 orders of magnitude larger than the other soft masses. The latter problem is caused by the decay of the modulus whose branching ratio into the gravitino pair is sizable. In this paper, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this axionic mirage mediation, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around 1010 GeV to 1012 GeV due to the supersymmetry breaking effects, and the μ problem can be solved naturally. Furthermore, in our model, the lightest supersymmetric particle (LSP) is the axino, that is, the superpartner of the axion. The overabundance of the LSPs due to decays of the modulus/gravitino, which is the most serious cosmological difficulty in the mirage mediation, can be avoided if the axino is sufficiently light. The next-LSPs (NLSPs) produced by the gravitino decay eventually decay into the axino LSPs, yielding the dominant component of the axinos remaining today. It is shown that the axino with a mass of O(100) MeV is naturally realized, which can constitute the dark matter of the Universe, with a free-streaming length of the order of 0.1 Mpc. The saxion, the real scalar component of the axion supermultiplet, can also be cosmologically harmless due to the dilution of the modulus decay. The lifetime of the NLSP is relatively long, but much shorter than 1 sec, when the big-bang nucleosynthesis commences. The decay of the NLSP would provide intriguing collider signatures
Nakamura, Shuntaro; Okumura, Ken-ichi; Yamaguchi, Masahiro
2008-01-01
In this talk, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this \\textit{axionic mirage mediation}, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around $10^{10}$ GeV to $10^{12}$ GeV due to the supersymmetry breaking effects. The problems in the original mirage mediation such as the $\\mu$-problem and the moduli problem can be solved simultaneouly. Furthermore, in our model the axino, which is the superpartner ...
Nakamura, Shuntaro; Yamaguchi, Masahiro
2008-01-01
Although the mirage mediation is one of the most plausible mediation mechanisms of supersymmetry breaking, it suffers from two crucial problems. One is the \\mu-/B \\mu-problem and the second is the cosmological one. The former stems from the fact that the B parameter tends to be comparable with the gravitino mass, which is two order of magnitude larger than the other soft masses. The latter problem is caused by the decay of the modulus whose branching ratio into the gravitino pair is sizable. In this paper, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this \\textit{axionic mirage mediation}, it is shown that the PQ symmetry breaking scale is dynamically determined around 10^{10-12} GeV due to the supersymmetry breaking effects, and the \\mu-problem can be solved naturally. Furthermore, in our model, the lightest supersymmetric particle (LSP) is the axino, that is the superpartner of the axion. The overabundance of the LSPs due to decays of modulus/gravitino, which is...
International Nuclear Information System (INIS)
We illustrate, taking a top-down point of view, how axions and other very weakly interacting sub-eV particles (WISPs) arise in the course of compactification of the extra spatial dimensions in string/M-theory. (orig.)
Eclipses could clarify axion mystery
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)
Wilczek, F.
Recent developments in theories of monopoles and axions are summarized, along with several implications. Present day monopoles are relics of early Big Bang processes. The remaining flux may be too small to detect, unless a local enhancement exists, such as a monopole cloud orbiting the sun. The 10 to the 16th GeV inertia of monopoles would require trapping in a magnetic bottle by a specially designed spacecraft. Degenerate monopoles may participate in the strong interactions and may not conserve the baryon number during the interaction. Axions have been postulated as the dynamical theta-field which describes the overall phase of the quark mass matrix. Energy transfer in stars could be accounted for by axions. At high temperatures, such as during the Big Bang, the axion would lose its mass, but in later epochs would be invisible and could account for the missing mass of the universe.
Axions, majorons and neutrino masses
International Nuclear Information System (INIS)
We point out that there is an intimate connection between the seesaw scale for the light neutrinos and the invisible axion scale based on a series of recent investigations on the neutrino masses and mixings within a class of realistic SO(10) models. We can then extend the standard model accordingly so that both the standard invisible axion and majoron can be treated in a naturally unified manner. 7 refs
Ultrasensitive Searches for the Axion
Energy Technology Data Exchange (ETDEWEB)
van Bibber, K A; Rosenberg, L J
2006-07-14
The axion, a hypothetical elementary particle arising from a compelling solution to the strong-CP problem, has eluded discovery for three decades. Experiments based on coherent axion-photon mixing in strong magnetic fields are just now reaching the sensitivity to detect it, either as the dark matter or as a component of the solar flux. Although of lower sensitivity, purely laboratory experiments hold potential for surprise.
Two applications of axion electrodynamics
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.
Backreacted Axion Field Ranges in String Theory
Baume, Florent
2016-01-01
String theory axions are interesting candidates for fields whose potential might be controllable over super-Planckian field ranges and therefore as possible candidates for inflatons in large field inflation. Axion monodromy scenarios are setups where the axion shift symmetry is broken by some effect such that the axion can traverse a large number of periods potentially leading to super-Planckian excursions. We study such scenarios in type IIA string theory where the axion shift symmetry is broken by background fluxes. In particular we calculate the backreaction of the energy density induced by the axion vacuum expectation value on its own field space metric. We find universal behaviour for all the compactifications studied where up to a certain critical axion value there is only a small backreaction effect. Beyond the critical value the backreaction is strong and implies that the proper field distance as measured by the backreacted metric increases at best logarithmically with the axion vev, thereby placing s...
Axion: Mass -- Dark Matter Abundance Relation
CERN. Geneva
2016-01-01
The axion is a hypothetical particle which would explain why QCD is approximately T-conserving, and is also an excellent Cold Dark Matter candidate. It should be possible to make a clean theoretical prediction relating the dark matter density in axions and the axion mass (under reasonable assumptions about inflation). But the axion's early-Universe dynamics, which establish its density as dark matter, are unexpectedly rich in a way which is only starting to yield to quantitative numerical study.
Is the invisible hadronic axion always harmless
International Nuclear Information System (INIS)
In the Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) axion model, if the invisible axion is hadronized (i.e. if the axion is made to decouple from leptons at tree level), it will be accompanied by a visible real Goldstone boson which interacts with both leptons and quarks. Consequently, the Higgs field coupled to right-handed leptons must also couple to right-handed d- or μ-type quark singlets. Astrophysical bounds on viable hadronic axions are discussed
Experimental Searches for the Axion and Axion-like Particles
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...
Interaction of axions with relativistic spinning particles
Popov, V. A.; Balakin, A. B.
2016-05-01
We consider a covariant phenomenological model, which describes an interaction between a pseudoscalar (axion) field and massive spinning particles. The model extends the Bagrmann-Michel-Telegdy approach in application to the axion electrodynamics. We present some exact solutions and discuss them in the context of experimental tests of the model and axion detection.
Active galaxies can make axionic dark energy
Dimopoulos, Konstantinos; Cormack, Sam
2016-01-01
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.
Interaction of axions with relativistic spinning particles
Popov, V A
2016-01-01
We consider a covariant phenomenological model, which describes an interaction between a pseudoscalar (axion) field and massive spinning particles. The model extends the Bagrmann-Michel-Telegdy approach in application to the axion electrodynamics. We present some exact solutions and discuss them in the context of experimental tests of the model and axion detection.
Axion landscape and natural inflation
International Nuclear Information System (INIS)
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
The axion mass in modular invariant supergravity
International Nuclear Information System (INIS)
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)
Theory of Light Scattering in Axion Electrodynamics
Ochiai, Tetsuyuki
2012-09-01
Taking account of the axion term in the Maxwell Lagrangian, we present a rigorous theory of light scattering in piecewise-constant axion fields. In particular, we focus on axionic substances with confined and/or curved geometries, and the scattering matrices of an axionic slab, cylinder, and sphere are derived analytically. The axion term generates a surface current with off-diagonal optical conductivity, giving rise to a new type of photospin--orbit interaction. As a result, various novel light-scattering phenomena can take place. We demonstrate enhanced Faraday rotation, parity-violating light scattering, and strong perturbation of dipole radiation.
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.
Backreacted axion field ranges in string theory
Baume, Florent; Palti, Eran
2016-08-01
String theory axions are interesting candidates for fields whose potential might be controllable over super-Planckian field ranges and therefore as possible candidates for inflatons in large field inflation. Axion monodromy scenarios are setups where the axion shift symmetry is broken by some effect such that the axion can traverse a large number of periods potentially leading to super-Planckian excursions. We study such scenarios in type IIA string theory where the axion shift symmetry is broken by background fluxes. In particular we calculate the backreaction of the energy density induced by the axion vacuum expectation value on its own field space metric. We find universal behaviour for all the compactifications studied where up to a certain critical axion value there is only a small backreaction effect. Beyond the critical value the backreaction is strong and implies that the proper field distance as measured by the backreacted metric increases at best logarithmically with the axion vev, thereby placing strong limitations on extending the field distance any further. The critical axion value can be made arbitrarily large by the choice of fluxes. However the backreaction of these fluxes on the axion field space metric ensures a precise cancellation such that the proper field distance up to the critical axion value is flux independent and remains sub-Planckian. We also study an axion alignment scenario for type IIA compactifications on a twisted torus with four fundamental axions mixing to leave an axion with an effective decay constant which is flux dependent. There is a choice of fluxes for which the alignment parameter controlling the effective decay constant is unconstrained by tadpoles and can in principle lead to an arbitrarily large effective decay constant. However we show that these fluxes backreact on the fundamental decay constants so as to precisely cancel any enhancement leaving a sub-Planckian effective decay constant.
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...
Magnetic Scope Angles for Axions
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
Ultrasensitive searches for the axion
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)
Axion Cooling of Neutron Stars
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...
Axion-Assisted Electroweak Baryogenesis
Craig, Nathaniel
2010-01-01
We consider a hidden-valley gauge sector, G, with strong coupling scale Lambda~TeV and CP-violating topological parameter, theta, as well as a new axion degree of freedom which adjusts theta to near zero in the current universe. If the G-sector couples to the Standard Model via weak-scale states charged under both, then in the early universe it is possible for the CP-violation due to theta (which has not yet been adjusted to zero by the hidden axion) to feed in to the SM and drive efficient baryogenesis during the electroweak (EW) phase transition, independent of the effectively small amount of CP violation present in the SM itself. While current constraints on both the new axion and charged states are easily satisfied, we argue that the LHC can investigate the vast majority of parameter space where EW-baryogenesis is efficiently assisted, while the hidden axion should comprise a significant fraction of the dark matter density. In the supersymmetric version, the ``messenger'' matter communicating between the ...
Axion overview and the U.S. RF cavity axion search
Energy Technology Data Exchange (ETDEWEB)
Rosenberg, L.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States); van Bibber, K.A.
1998-01-01
The axion, a hypothetical elementary particle, originally emerged from a solution to the strong CP problem in QCD. Later, axions were recognized as good dark matter candidates. Dark matter axions have only feeble couplings to matter and radiation, so their detection offers considerable challenge. Nonetheless, a new generation of exquisitely sensitive searches is underway. One such effort, in the United States, has already achieved sensitivity to plausible halo dark matter axion to photon couplings.
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
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
CAST-CERN Axion Solar Telescope
International Nuclear Information System (INIS)
CAST (CERN Axion Solar Telescope) is a helioscope looking for axions coming from the solar core to the Earth. The experiment, located at CERN, is based on the Primakoff effect and uses a magnetic field of 9 T provided by a decommissioned LHC magnet. CAST is able to follow the Sun during sunrise and sunset and therefore three X-ray detectors are mounted on both ends of the magnet waiting for a photon from axion-to-photon conversion due to Primakoff effect. During its first phase, which concluded in 2004, CAST has been looking for axions with masses up to 0.02 eV. The second phase did already start and first data were taken in December 2005. CAST's second phase manages to reestablish the coherence needed to scan for axions with masses up to 0.83 eV by using a buffer gas. This enables the experiment to look into the theoretical regions for axions
Rotating Drops of Axion Dark Matter
Davidson, Sacha
2016-01-01
We consider how QCD axions produced by the misalignment mechanism could form galactic dark matter halos. We recall that stationary, gravitationally stable axion field configurations have the size of an asteroid with masses of order $10^{-13} $ solar masses (because gradient pressure is insufficient to support a larger object). We call such field configurations "drops". We explore whether rotating drops could be larger, and find that their mass could increase by a factor ~ 10. Remarkably this mass is comparable to the mass of miniclusters generated from misalignment axions in the scenario where the axion is born after inflation. We speculate that misalignment axions today are in the form of drops, contributing to dark matter like a distribution of asteroids (and not as a coherent oscillating background field). We consider some observational signatures of the drops, which seem consistent with a galactic halo made of axion dark matter.
Searching for Dark-Matter Axions
Rosenberg, Leslie
2016-03-01
The axion is a hypothetical elementary particle arising in the 1970's from an elegant solution to the Strong CP problem in Quantum Chromo Dynamics. Light QCD axions (masses technology has advanced to where such axions might be detected. Several large searches are in the construction and commissioning phase, with new projects in the development phase. There are also concepts for new detector technologies aimed at improving the sensitivity and axion mass-reach. These searches would have the potential to detect even the more pessimistically-coupled dark-matter axions should they contribute a fraction of the local Milky Way dark-matter halo. This talk discusses the dark-matter axion experimental landscape and the prospects for their discovery. Supported by the U.S. Department of Energy, Office of High Energy Physics.
On supersymmetric effective theories of axion
Energy Technology Data Exchange (ETDEWEB)
Higaki, Tetsutaro [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kitano, Ryuichiro [Tohoku Univ., Sendai (Japan). Dept. of Physics
2011-04-15
We study effective theories of an axion in spontaneously broken supersymmetric theories. We consider a system where the axion supermultiplet is directly coupled to a supersymmetry breaking sector whereas the standard model sector is communicated with those sectors through loops of messenger fields. The gaugino masses and the axion-gluon coupling necessary for solving the strong CP problem are both obtained by the same effective interaction. We discuss cosmological constraints on this framework. (orig.)
Dynamical Axion Field in Topological Magnetic Insulators
Li, Rundong; Jing WANG; Qi, Xiaoliang; Zhang, Shou-Cheng
2009-01-01
Axions are very light, very weakly interacting particles postulated more than 30 years ago in the context of the Standard Model of particle physics. Their existence could explain the missing dark matter of the universe. However, despite intensive searches, they have yet to be detected. In this work, we show that magnetic fluctuations of topological insulators couple to the electromagnetic fields exactly like the axions, and propose several experiments to detect this dynamical axion field. In ...
On supersymmetric effective theories of axion
International Nuclear Information System (INIS)
We study effective theories of an axion in spontaneously broken supersymmetric theories. We consider a system where the axion supermultiplet is directly coupled to a supersymmetry breaking sector whereas the standard model sector is communicated with those sectors through loops of messenger fields. The gaugino masses and the axion-gluon coupling necessary for solving the strong CP problem are both obtained by the same effective interaction. We discuss cosmological constraints on this framework. (orig.)
Axion Dark Matter Detection with Cold Molecules
Graham, Peter W.; Rajendran, Surjeet
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 Sch...
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 m_{a} 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.
Fast Radio Bursts from Axion Stars
Iwazaki, Aiichi
2014-01-01
Axions are one of the most promising candidates of dark matter. The axions have been shown to form miniclusters with masses $\\sim 10^{-12}M_{\\odot}$ and to become dominant component of dark matter. These axion miniclusters condense to form axion stars. We show a possible origin of fast radio bursts ( FRBs ) by assuming the axion stars being dark matter: FRBs arise from the collisions between the axion stars and neutron stars. The FRBs are caused by the rapid conversion of the axions into electromagnetic fields under strong magnetic fields. Electric fields are induced on the axion stars under strong magnetic fields of neutron stars. The electric fields parallel to the magnetic fields oscillate with a frequency and make electrons in atmospheres of neutron stars coherently oscillate. Thus, the coherent radiations are emitted. The observed frequencies ( $\\sim 1.4$GHz ) of the bursts are given by the axion mass $m_a$ such as $m_a/2\\pi\\simeq 2.3\\,\\mbox{GHz}\\,\\big(m_a/10^{-5}\\mbox{eV}\\big)$. The frequency is affecte...
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.
Prospects for the CERN Axion Solar Telescope Sensitivity to 14.4 keV Axions
Jakovcic, K; Aune, S; Avignone, F T; Barth, K; Belov, A; Beltrn, B; Bruninger, H; Carmona, J M; Cebrin, S; Collar, J I; Dafni, T; Davenport, M; Di Lella, L; Eleftheriadis, C; Fanourakis, G K; Ferrer-Ribas, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, Ioanis; Gninenko, S; Hasinoff, M D; Heinsius, F H; Hoffmann, Dieter H H; Irastorza, I G; Jacoby, J; Kang, D; Knigsmann, K; Kotthaus, R; Krcmar, M; Kousouris, a K; Kuster, M; Laki, B; Lasseur, C; Liolios, A; Ljubici, A; Lutz, G; Luzn, G; Miller, D W; Morales, A; Morales, J; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, G; Ruz, J; Riege, H; Semertzidis, Y K; Serpico, Pasquale Dario; Stewart, o L; Vieira, J D; Villar, J; Vogel, J; Walckiers, L; Zioutas, K; Jakovcic, Kresimir
2007-01-01
The CERN Axion Solar Telescope (CAST) is searching for solar axions using the 9.0 T strong and 9.26 m long transverse magnetic field of a twin aperture LHC test magnet, where axions could be converted into X-rays via reverse Primakoff process. Here we explore the potential of CAST to search for 14.4 keV axions that could be emitted from the Sun in M1 nuclear transition between the first, thermally excited state, and the ground state of 57Fe nuclide. Calculations of the expected signals, with respect to the axion-photon coupling, axion-nucleon coupling and axion mass, are presented in comparison with the experimental sensitivity.
Kamionkowski, Marc
1997-01-01
There is almost universal agreement among cosmologists that most of the matter in the Universe is dark, and there are very good reasons to believe that most of this dark matter must be nonbaryonic. The two leading candidates for this dark matter are axions and weakly-interacting massive particles (WIMPs), such as the neutralino in supersymmetric extensions of the standard model. I discuss the arguments for these two dark-matter candidates and review techniques for discovery of these dark-matt...
Axion mass limit from observations of the neutron star in Cassiopeia A
Energy Technology Data Exchange (ETDEWEB)
Leinson, Lev B., E-mail: leinson@yandex.ru [Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation of the Russian Academy of Science (IZMIRAN), 142190 Troitsk, Moscow (Russian Federation)
2014-08-01
Direct Chandra observations of a surface temperature of isolated neutron star in Cassiopeia A (Cas A NS) and its cooling scenario which has been recently simultaneously suggested by several scientific teams put stringent constraints on poorly known properties of the superfluid neutron star core. It was found also that the thermal energy losses from Cas A NS are approximately twice more intensive than it can be explained by the neutrino emission. We use these unique data and well-defined cooling scenario to estimate the strength of KSVZ axion interactions with neutrons. We speculate that enlarged energy losses occur owing to emission of axions from superfluid core of the neutron star. If the axion and neutrino losses are comparable we find c{sub n}{sup 2}m{sub a}{sup 2}∼ 5.7× 10{sup -6} eV{sup 2}, where m{sub a} is the axion mass, and c{sub n} is the effective Peccei-Quinn charge of the neutron. (Given the QCD uncertainties of the hadronic axion models, the dimensionless constant c{sub n} could range from -0.05 to 0.14.)
Vacuum selection on axionic landscapes
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.
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...
Some Considerations About Podolsky-Axionic Electrodynamics
Gaete, Patricio(Departmento de Física and Centro Científico-Tecnológico de Valparaíso, Universidad Técnica Federico Santa María, Valparaiso, Chile)
2011-01-01
For a Podolsky-axionic electrodynamics, we compute the interaction potential within the structure of the gauge-invariant but path-dependent variables formalism. The result is equivalent to that of axionic electrodynamics from a new noncommutative approach, up to first order in $\\theta$.
Fleury, Leesa M.; Moore, Guy D.
2016-05-01
If the axion exists and if the initial axion field value is uncorrelated at causally disconnected points, then it should be possible to predict the efficiency of cosmological axion production, relating the axionic dark matter density to the axion mass. The main obstacle to making this prediction is correctly treating the axion string cores. We develop a new algorithm for treating the axionic string cores correctly in 2+1 dimensions. When the axionic string cores are given their full physical string tension, axion production is about twice as efficient as in previous simulations. We argue that the string network in 2+1 dimensions should behave very differently than in 3+1 dimensions, so this result cannot be simply carried over to the physical case. We outline how to extend our method to 3+1D axion string dynamics.
Fleury, Leesa M
2016-01-01
If the axion exists and if the initial axion field value is uncorrelated at causally disconnected points, then it should be possible to predict the efficiency of cosmological axion production, relating the axionic dark matter density to the axion mass. The main obstacle to making this prediction is correctly treating the axion string cores. We develop a new algorithm for treating the axionic string cores correctly in 2+1 dimensions. When the axionic string cores are given their full physical string tension, axion production is about twice as efficient as in previous simulations. We argue that the string network in 2+1 dimensions should behave very differently than in 3+1 dimensions, so this result cannot be simply carried over to the physical case. We outline how to extend our method to 3+1D axion string dynamics.
Fermion production during and after axion inflation
International Nuclear Information System (INIS)
We study derivatively coupled fermions in axion-driven inflation, specifically mϕ2ϕ2 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
Oscillating Chiral Tensor Spectrum from Axionic Inflation
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.
A Search for Axions and massive neutrinos
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.
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.
Solar axion search with the CAST experiment
Arik, E; Autiero, D; Barth, K; Belov, A; Beltrán, B; Borghi, S; Boydag, F S; Bräuninger, H; Cantatore, G; Carmona, J M; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Di Lella, L; Dogan, O B; Eleftheriadis, C; Elias, N; Fanourakis, G K; Ferrer-Ribas, E; Fischer, H; Franz, J; Galan, J; Gazis, E; Geralis, T; Giomataris, Yu; Gninenko, S; Gomez, H; Hasinoff, M; Heinsius, F H; Hikmet, I; Hoffmann, D H H; Irastorza, I G; Jacoby, J; Jakovcic, K; Kang, D; Karageorgopoulou, T; Karuza, M; Königsmann, K C; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Lakic, B; Lasseur, C; Liolios, A; Ljubcici, A; Lozza, V; Lutz, G; Luzón, G; Miller, D; Morales, J; Niinikoski, T; Nordt, A; Ortiz, A; Papaevangelou, T; Pivovaroff, M; Placci, A; Raiteri, G; Raffelt, G; Riege, H; Rodríguez, A; Ruz, J; Savvidis, I; Semertzidis, Y; Serpico, P; Solanki, S K; Soufli, R; Stewart, L; Tsagri, M; Van Bibber, K; Villar, J; Vogel, J; Walckiers, L; Zioutas, K
2008-01-01
The CAST (CERN Axion Solar Telescope) experiment is searching for solar axions by their conversion into photons inside the magnet pipe of an LHC dipole. The analysis of the data recorded during the first phase of the experiment with vacuum in the magnet pipes has resulted in the most restrictive experimental limit on the coupling constant of axions to photons. In the second phase, CAST is operating with a buffer gas inside the magnet pipes in order to extent the sensitivity of the experiment to higher axion masses. We will present the first results on the $^4{He}$ data taking as well as the system upgrades that have been operated in the last year in order to adapt the experiment for the $^3{He}$ data taking. Expected sensitivities on the coupling constant of axions to photons will be given for the recent $^3{He}$ run just started in March 2008.
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
Bose-Einstein Condensation of Dark Matter Axions
Sikivie, P.; Yang, Q.
2009-01-01
We show that cold dark matter axions thermalize and form a Bose-Einstein condensate. 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 non-linear 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 microw...
Large Field Inflation from Axion Mixing
Shiu, Gary; Ye, Fang
2015-01-01
We study the general multi-axion systems, focusing on the possibility of large field inflation driven by axions. We find that through axion mixing from a non-diagonal metric on the moduli space and/or from St\\"uckelberg coupling to a U(1) gauge field, an effectively super-Planckian decay constant can be generated without the need of "alignment" in the axion decay constants. We also investigate the consistency conditions related to the gauge symmetries in the multi-axion systems, such as vanishing gauge anomalies and the potential presence of generalized Chern-Simons terms. Our scenario applies generally to field theory models whose axion periodicities are intrinsically sub-Planckian, but it is most naturally realized in string theory. The types of axion mixings invoked in our scenario appear quite commonly in D-brane models, and we present its implementation in type II superstring theory. Explicit stringy models exhibiting all the characteristics of our ideas are constructed within the frameworks of Type IIA ...
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......-photon coupling gaγ down to a few ×10−12 GeV−1 for a wide range of axion masses up to ∼ 0.25eV. This is an improvement over the currently best (3rd generation) axion helioscope, the CERN Axion Solar Telescope (CAST), of about 5 orders of magnitude in signal strength, corresponding to a factor ∼ 20 in the axion...... photon coupling. IAXO's sensitivity relies on the construction of a large superconducting 8-coil toroidal magnet of 20 m length optimized for axion research. Each of the eight 60cm diameter magnet bores is equipped with x-ray optics focusing the signal photons into ∼ 0.2cm2 spots that are imaged by very...
New potentials for string axion inflation
Kobayashi, Tatsuo; Oikawa, Akane; Otsuka, Hajime
2016-04-01
We propose a new type of axion inflation with complex structure moduli in the framework of type IIB superstring theory compactified on the 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 the mirror Calabi-Yau manifold. The axionic shift symmetry is broken down to the discrete one by the inclusion of the instantonic correction and certain three-form fluxes. Our proposed inflation scenario is compatible with Kähler moduli stabilization. We also study a typical reheating temperature in the case of complex structure moduli inflation.
A 2nd generation cosmic axion experiment
Hagmann, C; Stoeffl, W.; Van Bibber, K.; Daw, E.; Kinion, D.; Rosenberg, L; Sikivie, P.; Sullivan, N.; D. Tanner; Moltz, D.; Nezrick, F.; Turner, M; Golubev, N.; Kravchuk, L.
1995-01-01
An experiment is described to detect dark matter axions trapped in the halo of our galaxy. Galactic axions are converted into microwave photons via the Primakoff effect in a static background field provided by a superconducting magnet. The photons are collected in a high Q microwave cavity and detected by a low noise receiver. The axion mass range accessible by this experiment is 1.3-13 micro-eV. The expected sensitivity will be roughly 50 times greater than achieved by previous experiments i...
A 2nd generation cosmic axion experiment
Hagmann, C A; Van Bibber, K; Daw, E J; Kinion, D S; Rosenberg, L J; Sikivie, P; Sullivan, N; Tanner, D B; Moltz, D M; Nezrick, F A; Turner, M; Golubev, N A; Kravchuk, L V
1995-01-01
An experiment is described to detect dark matter axions trapped in the halo of our galaxy. Galactic axions are converted into microwave photons via the Primakoff effect in a static background field provided by a superconducting magnet. The photons are collected in a high Q microwave cavity and detected by a low noise receiver. The axion mass range accessible by this experiment is 1.3-13 micro-eV. The expected sensitivity will be roughly 50 times greater than achieved by previous experiments in this mass range. The assembly of the detector is well under way at LLNL and data taking will start in mid-1995.
Gravitational Waves from Axion Monodromy
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...
2008-01-01
The CERN relay race will take place around the Meyrin site on Thursday 5 June starting at 12:15 p.m. 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 how to register your team for the relay race are given on the Staff Association Bulletin web site. You can access the online registration form at: http://cern.ch/club-running-relay/form.html
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.
Axion monodromy inflation with sinusoidal corrections
Kobayashi, Tatsuo; Yamaguchi, Yuya
2014-01-01
We study the axion monodromy inflation with a non-perturbatively generated sinusoidal term. The potential form is a mixture between the natural inflation and the axion monodromy inflation potentials. The sinusoidal term is subdominant in the potential, but leaves significant effects on the resultant fluctuation generated during inflation. A larger tensor-to-scalar ratio can be obtained in our model. We study two scenarios, single inflation scenario and the double inflation scenario. In the first scenario, the axion monodromy inflation with a sufficient number of e-fold generates a larger tensor-to-scalar ratio about $0.1 - 0.15$ but also a tiny running of spectral index. In the second scenario of double inflation, axion monodromy inflation is its first stage and, we assume another inflation follows. In this case, our model can realize a larger tensor-to-scalar ratio and a large negative running of spectral index simultaneously.
Nonrelativistic Effective Field Theory for Axions
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 $\\psi^*\\psi$.
Cavity Microwave Searches for Cosmological Axions
CERN. Geneva
2005-01-01
The lecture will cover the searches for dark matter axions based on the microwave cavity experiment of Sikivie. The topics will begin with a brief overview of halo dark matter, and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described, and practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of the lecture will be the two complementary strategies for ultra-low noise detection of the microwave photons - the "photon-as-wave" approach (i.e. conventional heterojunction amplifiers and soon quantum-limited SQUID devices), and "photon-as-particle" (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The lecture will conclude with a discussion of future plans and challenges for the microwave ca...
Dark-matter QCD-axion searches.
Rosenberg, Leslie J
2015-10-01
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
Gravity wave and model-independent axion
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.
Youn, Sungwoo
2016-07-01
The axion, a hypothetical fundamental particle, was postulated as an attractive solution to the CP problem in quantum chromodynamics and believed to be an ideal candidate for the cold dark matter. The Center for Axion and Precision Physics Research of the Institute for Basic Science has launched a state of the art experiment to search for the hypothesised new particle using microwave resonant cavities. I will discuss R&D efforts at our center and plans for the experiment.
An experiment to search for galactic axions
International Nuclear Information System (INIS)
Results are presented from a search for axions in the mass range of .51 X 10-5 to 1 X 10-5eV, which may make up the dark matter halo of the galaxy. The detector used in the search consists of a microwave cavity placed in the strong magnetic field of a superconducting solenoid magnet. The energy in the TM010 mode of the cavity is monitored by a sensitive microwave receiver as the frequency of the mode is swept. The predicted experimental signature of galactic halo axions is a narrow signal, with a Qa = f/Δf ∼ 3 X 106, which is expected when the resonant frequency of the cavity corresponds to the mass of the axion. An experimental limit on the coupling times the density of (gaγγ/ma)2 ρa ≤ 2 x 10-40 for an axion linewidth ≤ 400 Hz with a 97% confidence level has been obtained. The theoretical prediction is (gaγγ/ma)2ρa ∼ 3.9 x 10-44 with ρa = 300 MeV/cm3. The corresponding limit in gaγγ ≤ 7 x 10-14 GeV-1 at an axion frequency f = 2 GeV and depends linearly on axion mass
Black hole formation from axion stars
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 ...
Photon - axion conversions in a periodic electromagnetic field with axion frequency
International Nuclear Information System (INIS)
The conversion of photons into axions in a periodic external electromagnetic field with axion frequency is considered in detail by Feynman methods. The differential cross sections are given. It is shown that there is a resonant conversion for the considered process. (author)
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...
Discovering the QCD Axion with Black Holes and Gravitational Waves
Arvanitaki, Asimina; Baryakhtar, Masha; Huang, Xinlu
2014-01-01
Advanced LIGO may be the first experiment to detect gravitational waves. Through superradiance of stellar black holes, it may also be the first experiment to discover the QCD axion with decay constant above the GUT scale. When an axion's Compton wavelength is comparable to the size of a black hole, the axion binds to the black hole, forming a "gravitational atom." Through the superradiance process, the number of axions occupying the bound levels grows exponentially, extracting energy and angu...
Small field axion inflation with sub-Planckian decay constant
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.
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.
Dynamical axion string, screw dislocation in Weyl semimetals and Axion insulators
You, Yi-Zhi; Cho, Gil Young; Hughes, Taylor
We study the interplay between the geometry and axion string resulting from a chiral symmetry breaking in 3D. The chiral symmetry is spontaneously broken by charge density wave (CDW) order parameter nesting two Weyl points, which turns it into an axion insulator. The phase fluctuation of the CDW order parameter acts as a dynamical axion field coupled to electromagnetic field via θF ∧ F term. When the axion insulator is coupled with the background geometry with torsional defects, i.e. screw dislocations, there is a novel interplay between the dislocation and the dynamical axion string. First, we show that the screw dislocation traps an axial charge. This then implies that if an axion string braids with a parallel screw dislocation, there is Berry phase accumulated during the braiding procedure. In addition, the cubic coupling between the axial current and the torsion bilinear shows the Berry phase accumulated by the three-loop braiding procedure, where we braid one dislocation loop around the other dislocation loop where the both are linked by an axion string loop. We also observe a chiral magnetic effect induced by a screw dislocation in the absence of chemical potential imbalance between Weyl points.
You, Yizhi; Cho, Gil Young; Hughes, Taylor L.
2016-08-01
In this paper, we investigate the theory of dynamical axion strings 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 θ (x ⃗,t ) and couple to electromagnetic field via Lθ=θ/(x ⃗,t ) 32 π2 ɛσ τ ν μFσ τFν μ. Additionally, when the axion insulator is coupled to deformations of the background geometry/strain fields via torsional defects, e.g., screw dislocations, there is interesting interplay between the crystal dislocations and dynamical axion strings. For example, the screw dislocation traps axial charge, and there is a Berry phase accumulation when an axion string (which carries axial flux) is braided with a screw dislocation. In addition, a cubic coupling between the axial current and the geometry fields is nonvanishing and indicates a Berry phase accumulation during a particular three-loop braiding procedure where a dislocation loop is braided with another dislocation and they are both threaded by an axion string. We also observe a chiral magnetic effect induced by a screw dislocation density in the absence of a nodal energy imbalance between Weyl points and describe an additional chiral geometric effect and a geometric Witten effect.
Axion from Quivers in Type II Superstrings
Belhaj, Adil; del Moral, Maria Pilar Garcia
2015-01-01
We investigate a string-inspired axion extension of the standard model obtained from Type II superstrings using quiver method. In the first part, we discuss intersecting Type IIA D6-branes wrapping non trivial 3-cycles in the presence of the Peccei-Quinn symmetry U(1)$_{PQ}$. Concretely, a complex scalar field $\\phi =\\rho exp(\\frac{i\\sigma}{f_{\\sigma}})$, where $\\sigma$ is a closed string axion generates a general fermion Yukawa coupling weighted by a flavor-dependent power $n_{f}$ taking specific values. Using string theory and standard model data, we find that the corresponding axion window is in the allowed range $10^{9}GeV\\leq f_{\\sigma}\\leq 10^{12}GeV $ matching with the recent cosmological results. Then, we extend these results to the case of the hyperbolic quiver whose the moduli is related to the stringy axion using root systems of ADE Lie algebras. For the hyperbolic quiver case, we observe that the closed axion decay constant becomes disentangled from the string scale.
Lattice QCD input for axion cosmology
Berkowitz, Evan; Rinaldi, Enrico
2015-01-01
One intriguing BSM particle is the QCD axion, which could simultaneously provide a solution to the Strong CP problem and account for some, if not all, of the dark matter density in the universe. This particle is a pNGB of the conjectured Peccei-Quinn (PQ) symmetry of the Standard Model. Its mass and interactions are suppressed by a heavy symmetry breaking scale, $f_a$, whose value is roughly greater than $10^{9}$ GeV (or, conversely, the axion mass, $m_a$, is roughly less than $10^4\\ \\mu \\text{eV}$). The density of axions in the universe, which cannot exceed the relic dark matter density and is a quantity of great interest in axion experiments like ADMX, is a result of the early-universe interplay between cosmological evolution and the axion mass as a function of temperature. The latter quantity is proportional to the second derivative of the QCD free energy with respect to the CP-violating phase, $\\theta$. However, this quantity is generically non-perturbative and previous calculations have only employed ins...
Axion-dilaton cosmology and dark energy
International Nuclear Information System (INIS)
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.)
Coupled Boltzmann computation of mixed axion neutralino dark matter in the SUSY DFSZ axion model
International Nuclear Information System (INIS)
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 fa∼< 6× 1012 GeV where the bulk of parameter space tends to be axion-dominated. For SUA with allowed saxion-axion couplings (ξ =1), then fa values up to ∼ 1014 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 fa∼ 1015–1016 GeV where large entropy dilution from CO-produced saxions leads to allowed models
Dynamical Axion String, Torsion Defects in Axion Insulator and Weyl Semimetals
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\
Measuring a piecewise constant axion field in classical electrodynamics
Energy Technology Data Exchange (ETDEWEB)
Obukhov, Yuri N. [Institute for Theoretical Physics, University of Cologne, 50923 Cologne (Germany)]. E-mail: yo@thp.uni-koeln.de; Hehl, Friedrich W. [Institute for Theoretical Physics, University of Cologne, 50923 Cologne (Germany)
2005-06-27
In order to settle the problem of the 'Post constraint' in material media, we consider the propagation of a plane electromagnetic wave in a medium with a piecewise constant axion field. Although a constant axion field does not affect the wave propagation in a homogeneous medium, we show that the reflection and transmission of a wave at an interface between the two media is sensitive to the difference of the axion values. This observation can be used to determine experimentally the axion piece in matter despite the fact that a constant axion value does not contribute to the Maxwell equations.
Measuring a piecewise constant axion field in classical electrodynamics
Obukhov, Yu N; Obukhov, Yuri N.; Hehl, Friedrich W.
2005-01-01
In order to settle the problem of the "Post constraint" in material media, we consider the propagation of a plane electromagnetic wave in a medium with a piecewise constant axion field. Although a constant axion field does not affect the wave propagation in a homogeneous medium, we show that the reflection and transmission of a wave at an interface between the two media is sensitive to the difference of the axion values. This observation can be used to determine experimentally the axion piece in matter despite the fact that a constant axion value does not contribute to the Maxwell equations.
Constraining the Axion Portal with B -> K l+ l-
Freytsis, Marat; Thaler, Jesse
2009-01-01
We investigate the bounds on axion-like states from flavor-changing neutral current b->s decays, assuming the axion couples to the standard model through mixing with the Higgs sector. Such GeV-scale axions have received renewed attention in connection with observed cosmic ray excesses. We find that existing B->K l+ l- data impose stringent bounds on the axion decay constant in the multi-TeV range, relevant for constraining the "axion portal" model of dark matter. Such bounds also constrain light Higgs scenarios in the NMSSM. These bounds can be improved by dedicated searches in B-factory data and at LHCb.
SQUID-based Resonant Detection of Axion Dark Matter
Popov, Vladimir
2014-01-01
A new method for searching for Dark Matter axions is proposed. It is shown that a two-contact SQUID can detect oscillating magnetic perturbations induced by the axions in a strong inhomogeneous magnetic field. A resonant signal is a steplike response in the SQUID current-voltage characteristic at a voltage corresponding to the axion mass with a height depending on the axion energy density near the Earth. The proposed experimental technique appears to be sensitive to the axions with masses $m_a\\lesssim 10^{-4}$ eV, which is well-motivated by current researches both in cosmology and in particle physics.
Resonance detection of dark matter axions using a DC SQUID
Popov, V. A.
2016-02-01
A method for detecting dark matter axions in which a dc SQUID serves as a detector is proposed. The SQUID is shown to be able to detect the magnetic field perturbations induced by its interaction with axions. The resonance signal appears as a current step in the SQUID current-voltage characteristic. The voltage of the step corresponds to the axion mass, while its height depends on the axion energy density in near-Earth space. The proposed method is aimed at detecting axions with masses m a ≲ 10-4 eV, which are of interest for both cosmology and particle physics.
Axion searches at CERN with the CAST Telescope
al, C. Eleftheriadis et
2003-01-01
The CERN Axion Solar Telescope (CAST) searches for axions coming from photon to axion conversion in the sun's core, as stated by the Primakoff effect. Axions arise in particle physics as a consequence of the breaking of Peccei-Quinn symmetry which has been introduced as a solution to the strong CP problem. As cosmological axions they are candidates for at least some part of cold Dark Matter.They are also expected to be produced copiously in stellar interiors with energies as high as the therm...
Discrete Abelian gauge symmetries and axions
Honecker, Gabriele
2015-01-01
We combine two popular extensions of beyond the Standard Model physics within the framework of intersecting D6-brane models: discrete Zn symmetries and Peccei-Quinn axions. The underlying natural connection between both extensions is formed by the presence of massive U(1) gauge symmetries in D-brane model building. Global intersecting D6-brane models on toroidal orbifolds of the type T6/Z2N and T6/Z2xZ2M with discrete torsion offer excellent playgrounds for realizing these extensions. A generation-dependent Z2 symmetry is identified in a global Pati-Salam model, while global left-right symmetric models give rise to supersymmetric realizations of the DFSZ axion model. In one class of the latter models, the axion as well as Standard Model particles carry a non-trivial Z3 charge.
Dimopoulos, Savas; Huang, Junwu; Marques-Tavares, Gustavo
2016-01-01
We present a model where the 750 GeV resonance plays a fundamental role as the QCD axion. Conformal dynamics and strong CP considerations account for the coincidence of the weak scale, the axion mass, and the scale of spontaneous PQ breaking. A benchmark minimal model predicts just a pseudoscalar color octet at 1 TeV and heavier colored states carrying a new strong force accessible at future hadron colliders. This model is predictive as after fixing the 750 GeV mass and the diphoton rate, there are only two free choices of hypercharge assignment which completely determine the mass, decay modes and widths of the axion and the color octet.
Nonminimal Einstein-Maxwell-Vlasov-axion model
Balakin, Alexander B; Zayats, Alexei E
2014-01-01
We establish a new self-consistent system of equations accounting for a nonminimal coupling of the cooperative gravitational, electromagnetic and pseudoscalar (axion) fields in a multi-component relativistic plasma. The axionic extension of the nonminimal Einstein-Maxwell-Vlasov theory is based on two consistent procedures. First, we use the Lagrange formalism to obtain nonminimal equations for the gravitational, electromagnetic and pseudoscalar fields with the additional sources generated in plasma. Second, we use the Vlasov version of the relativistic kinetic theory of the plasma, guided by the cooperative macroscopic electromagnetic, gravitational and axionic fields, to describe adequately the response of the plasma on the variations of these fields. In order to show the self-consistency of this approach we check directly the compatibility conditions for the master equations for the cooperative fields. Using these compatibility conditions we reconstruct the ponderomotive force, which acts on the plasma par...
Discrete Abelian gauge symmetries and axions
Honecker, Gabriele; Staessens, Wieland
2015-07-01
We combine two popular extensions of beyond the Standard Model physics within the framework of intersecting D6-brane models: discrete ℤn symmetries and Peccei-Quinn axions. The underlying natural connection between both extensions is formed by the presence of massive U(1) gauge symmetries in D-brane model building. Global intersecting D6-brane models on toroidal orbifolds of the type T6/ℤ2N and T6/ℤ2 × ℤ2M with discrete torsion offer excellent playgrounds for realizing these extensions. A generation-dependent ℤ2 symmetry is identified in a global Pati-Salam model, while global left-right symmetric models give rise to supersymmetric realizations of the DFSZ axion model. In one class of the latter models, the axion as well as Standard Model particles carry a non-trivial ℤ3 charge.
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.
Astrophysical axion bounds diminished by screening effects
International Nuclear Information System (INIS)
''Invisible axions'' could be produced in stellar interiors through Compton- and Primakoff-type photoproduction and through bremsstrahlung processes. We point out that in a plasma screening effects lead to important reductions of these emission rates. Limits on the axion mass and interaction strength are thereby relaxed to values less restrictive than limits previously thought to be firm. For the case of the Sun the Primakoff rate is reduced by two orders of magnitude. This process is the dominant emission mechanism for Kim-Shifman-Vainshtein-Zakharov- (KSVZ) type axions which do not couple directly to electrons. The mass limit is then relaxed by an order of magnitude to m/sub a/2β of the model equals unity. Our results can be easily translated to other hypothetical pseudoscalar particles if they are light compared with typical stellar temperatures
International Nuclear Information System (INIS)
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
The CERN axion solar telescope (CAST)
Aalseth, C E; Autiero, D; Avignone, F T; Barth, K; Bowyer, S M; Bräuninger, H; Brodzinski, R L; Carmona, J M; Cebrián, S; Celebi, G; Cetin, S A; Collar, J I; Creswick, R; Delbart, A; Delattre, M; Di Lella, L; De Oliveira, R; Eleftheriadis, C; Erdutan, N; Fanourakis, G K; Farach, H A; Fiorini, C; Geralis, T; Giomataris, Ioanis; Girard, T A; Gninenko, S N; Golubev, N A; Hasinoff, M D; Hoffmann, D; Irastorza, I G; Jacoby, J; Jeanneau, F; Knopf, M A; Kovzelev, A; Kotthaus, R; Krcmar, M; Krecak, Z; Lakic, B; Liolios, A; Ljubicic, A; Lutz, Gerhard; Longoni, A; Luzón, 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; Sampietro, 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, Konstantin
2002-01-01
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 - sup 1 sup 1 GeV sup - sup 1 can be reached for m subalpha <= 10 sup - sup 2 eV, and with a gas filled tube-can reach g alpha gamma gamma <= 10 sup - sup 1 sup 0 GeV sup - sup 1 for axion masses m subalpha < 2eV.
A Broadband Approach to Axion Dark Matter Detection
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.
CAST constraints on the axion-electron coupling
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.
Axion searches at CERN with the CAST Telescope
Eleftheriadis, C; Arik, E; Autiero, D; Avignone, F T; Barth, K; Bingol, E; Bräuninger, H; Brodzinski, R L; Carmona, J M; Cebrián, S; Cetin, S A; Chesi, Enrico Guido; Cipolla, G; Collar, J I; Creswick, R; Dafni, T; Davenport, M; De Oliveira, R; Dedoussis, S; Delbart, A; Di Lella, L; Fanourakis, G K; Farach, H A; Fischer, H; Formenti, F; Geralis, T; Glomataris, I; Gninenko, S N; Goloubev, N; Hartmann, R; Hasinoff, M D; Hoffmann, D; Irastorza, I G; Jacoby, J; Kang, D; Königsmann, K C; Kotthaus, R; Krcmar, M; Kuster, M; Lakic, B; Liolios, A; Ljubicic, A; Lutz, Gerhard; Luzón, G; Miley, H S; Morales, A; Morales, L; Mutterer, M; Nikolaidis, A; Ortiz, A; Papaevangelou, T; Placci, A; Raffelt, Georg G; Riege, H; Sarsa, M; Savvidis, I; Schopper, R; Semertzidis, Y K; Spanos, V C; Vasilelou, V; Villar, José Angel; Vullierme, B; Walckiers, L; Zachariadou, K; Zioutas, Konstantin
2003-01-01
The CERN Axion Solar Telescope (CAST) searches for axions coming from photon to axion conversion in the sun's core, as stated by the Primakoff effect. Axions arise in particle physics as a consequence of the breaking of Peccei-Quinn symmetry which has been introduced as a solution to the strong CP problem. As cosmological axions they are candidates for at least some part of cold Dark Matter.They are also expected to be produced copiously in stellar interiors with energies as high as the thermal photons undergoing photon to axion conversion. In our sun the axion energy spectrum peaks at about 4.4 keV, extending up to 10 keV. CAST collected preliminary data in 2002 and data taking with its full capability will start in the beginning of 2003.
Cosmological Perturbations of Axion with a Dynamical Decay Constant
Kobayashi, Takeshi
2016-01-01
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.
Drifting oscillations in axion monodromy
International Nuclear Information System (INIS)
We study the pattern of oscillations in the primordial power spectrum in axion monodromy inflation, accounting for drifts in the oscillation period that can be important for comparing to cosmological data. In these models the potential energy has a monomial form over a super-Planckian field range, with superimposed modulations whose size is model-dependent. The amplitude and frequency of the modulations are set by the expectation values of moduli fields. We show that during the course of inflation, the diminishing energy density can induce slow adjustments of the moduli, changing the modulations. We provide templates capturing the effects of drifting moduli, as well as drifts arising in effective field theory models based on softly broken discrete shift symmetries, and we estimate the precision required to detect a drifting period. A non-drifting template suffices over a wide range of parameters, but for the highest frequencies of interest, or for sufficiently strong drift, it is necessary to include parameters characterizing the change in frequency over the e-folds visible in the CMB. We use these templates to perform a preliminary search for drifting oscillations in a part of the parameter space in the Planck nominal mission data.
Universal constraints on axions from inflation
DEFF Research Database (Denmark)
Ferreira, R. Z.; Sloth, M. S.
2014-01-01
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......-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...
Non-Gaussianity from Axion Monodromy Inflation
DEFF Research Database (Denmark)
Hannestad, Steen; Haugboelle, Troels; R. Jarnhus, Philip;
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...
Conceptual Design of the International Axion Observatory (IAXO)
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...
Axion Dark Matter Detection with Cold Molecules
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...
Axion models with high scale inflation
Moroi, Takeo; Mukaida, Kyohei; Nakayama, Kazunori; Takimoto, Masahiro
2014-11-01
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.
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.
Axion hot dark matter bounds after Planck
Archidiacono, Maria; Mirizzi, Alessandro; Raffelt, Georg; Wong, Yvonne Y Y
2013-01-01
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_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_0 released by the Carnegie Hubble Program based on a recalibration of the Hubble Space Telescope Key Project sample. Leaving out the local H_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_a has been obtained from CMB data alone. Our axion limit is therefore not very sensitive to the tension between the Planck-inferred H_0 and the locally measured value. This is in contrast with the upper limit on the neutrino m...
Axion Models with High Scale Inflation
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.
Review of dark-matter axion experiments
Energy Technology Data Exchange (ETDEWEB)
van Bibber, K; Kinion, D
2000-08-30
We review the status of two ongoing large-scale searches for axions which may constitute the dark matter of our Milky Way halo. The experiments are based on the microwave cavity technique proposed by Sikivie, and marks a 'second-generation' to the original experiments performed by the Rochester-Brookhaven-Fermilab collaboration, and the University of Florida group.
Particle physics footprints of the invisible axion
International Nuclear Information System (INIS)
I discuss some particle physics expectations of a natural class of invisible axion models. These models require the presence of charged and neutral spin zero bosons of Fermi scale masses. Indeed, such excitations appear to be telltale signals for almost all viable cold dark matter scenarios. (orig.)
Cavity Microwave Searches for Cosmological Axions
Energy Technology Data Exchange (ETDEWEB)
Carosi, G; van Bibber, K
2007-01-22
This chapter will cover the search for dark matter axions based on microwave cavity experiments proposed by Pierre Sikivie. We will start with a brief overview of halo dark matter and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described as well as practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of this chapter will be the two complementary strategies for ultra-low noise detection of the microwave photons--the 'photon-as-wave' approach (i.e. conventional heterojunction amplifiers and soon to be quantum-limited SQUID devices), and 'photon-as-particle' (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The section will conclude with a discussion of future plans and challenges for the microwave cavity experiment.
Heavy axion in asymptotically safe QCD
Kobakhidze, Archil
2016-01-01
Assuming QCD exhibits an interacting fixed-point behaviour in the ultraviolet regime, I argue that the axion can be substantially heavier than in the conventional case of asymptotically free QCD due to the enhanced contribution of small size instantons to its mass.
A decommissioned LHC model magnet as an axion telescope
International Nuclear Information System (INIS)
The 8.4 T, 10 m long transverse magnetic field of a twin aperture LHC bending magnet can be utilized as a macroscopic coherent solar axion-to-photon converter. Numerical calculations show that the integrated time of alignment with the Sun would be 33 days/yr with the magnet on a tracking table capable of ±5 deg. in the vertical direction and ±40 deg. in the horizontal direction. The existing lower bound on the axion-to-photon coupling constant can be improved by a factor between 30 and 100 in 3 yr, i.e., gaγγ -11 GeV-1 for axion masses < or approx. 1 eV. This value falls within the existing open axion mass window. The same set-up can simultaneously search for low- and high-energy celestial axions, or axion-like particles, scanning the sky as the Earth rotates and orbits the Sun
Solar axion experiments using coherent Primakoff conversion in single crystals
International Nuclear Information System (INIS)
The results of a 1.94 kg · y pilot search for solar axions with an ultralow background Ge detector are reviewed. The detection method is based on Bragg-coherent Primakoff conversion of axions into photons when the momentum vectors of the axion and photon satisfy the Bragg condition. The theory of the experiment are presented for Ge and Te02 crystals. Future prospects of large volume experiments are discussed
Small Instanton Contribution to the Axion Potential in Supersymmetric Models
Choi, Kiwoon; Kim, Hyungdo
1998-01-01
Small size QCD instantons may spoil the axion solution to the strong CP problem if QCD is not asymptotically free at high energy scales. We examine this issue in supersymmetric models using a manifestly supersymmetric scheme to compute the axion potential induced by small size instantons. Applying this scheme for a class of illustrative models, it is found that the resulting high energy axion potential is highly model-dependent, but suppressed by more powers of the soft supersymmetry breaking...
Axion oscillations and the quark-hadron phase transition
International Nuclear Information System (INIS)
We consider the possibility that the quark-hadron phase transition occurs when the axion field passes through the minimum of its potential during its oscillation cycle. If this were to occur, the axion field would gain no energy from the associated increase in mass thus permitting the cosmological bound on the axion decay constant to be raised. However, we find that the probability of this happening is small. (orig.)
Accelerating dark-matter axion searches with quantum measurement technology
Zheng, Huaixiu; Silveri, Matti; 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 r...
The paradox of axions surviving primordial magnetic fields
Ahonen, J; Raffelt, G G; Ahonen, Jarkko; Enqvist, Kari; Raffelt, Georg
1995-01-01
In the presence of primordial magnetic fields the oscillating cosmic axion field drives an oscillating electric field. The ensuing dissipation of axions is found to be inversely proportional to the conductivity of the primordial plasma. This counterintuitive result is essentially equivalent to ``Zeno's paradox'' or the ``watched-pot effect'' of quantum mechanics. It implies that the standard predictions of the cosmic axion density remain unaltered even if primordial magnetic fields are strong.
Thermal axion constraints in non-standard thermal histories
Grin, Daniel; Smith, Tristan; Kamionkowski, Marc
2010-01-01
There is no direct evidence for radiation domination prior to big-bang nucleosynthesis, and so it is useful to consider how constraints to thermally-produced axions change in non-standard thermal histories. In the low-temperature-reheating scenario, radiation domination begins at temperatures as low as 1 MeV, and is preceded by significant entropy generation. Axion abundances are then suppressed, and cosmological limits to axions are significantly loosened. In a kination scenario, a more mode...
Search for Sub-eV Mass Solar Axions by the CERN Axion Solar Telescope with 3He Buffer Gas
International Nuclear Information System (INIS)
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 a aγ -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 ma < or approx. 1.15 eV, comfortably overlapping with cosmological hot dark matter bounds.
Natural inflation with multiple sub-Planckian axions
Choi, Kiwoon; Kim, Hyungjin; Yun, Seokhoon
2014-01-01
We extend the Kim-Nilles-Peloso (KNP) alignment mechanism for natural inflation to models with $N>2$ axions, which obtains a super-Planckian effective axion decay constant $f_{\\textrm{eff}}\\gg M_{Pl}$ through an alignment of the anomaly coefficients of multiple axions having sub-Planckian fundamental decay constants $f_0\\ll M_{Pl}$. The original version of the KNP mechanism realized with two axions requires that some of the anomaly coefficients should be of the order of $f_{\\textrm{eff}}/f_0$...
Results on axion physics from the CAST Experiment at CERN
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.
Constraining the Axion Portal with B -> K l+ l-
Freytsis, Marat; Ligeti, Zoltan; Thaler, Jesse
2009-01-01
We investigate the bounds on axionlike states from flavor-changing neutral current b->s decays, assuming the axion couples to the standard model through mixing with the Higgs sector. Such GeV-scale axions have received renewed attention in connection with observed cosmic ray excesses. We find that existing B->K l+ l- data impose stringent bounds on the axion decay constant in the multi-TeV range, relevant for constraining the "axion portal" model of dark matter. Such bounds also constrain lig...
Future cosmological sensitivity for hot dark matter axions
Archidiacono, Maria; Basse, Tobias; Hamann, Jan; Hannestad, Steen; Raffelt, Georg; Wong, Yvonne Y.Y
2015-01-01
We study the potential of a future, large-volume photometric survey to constrain the axion mass $m_a$ in the hot dark matter limit. Future surveys such as Euclid will have significantly more constraining power than current observations for hot dark matter. Nonetheless, the lowest accessible axion masses are limited by the fact that axions lighter than $\\\\sim 0.15$ eV decouple before the QCD epoch, assumed here to occur at a temperature $T_{\\\\rm QCD} \\\\sim 170$ MeV; this leaves an axion popula...
An improved cosmological bound on the thermal axion mass
Melchiorri, Alessandro; Mena Requejo, Olga; Slosar, Anze
2007-01-01
Relic thermal axions could play the role of an extra hot dark matter component in cosmological structure formation theories. By combining the most recent observational data we improve previous cosmological bounds on the axion mass m(a) in the so-called hadronic axion window. We obtain a limit on the axion mass m(a)< 0.42 eV at the 95% C.L. (m(a)< 0.72 eV at the 99% C.L.). A novel aspect of the analysis presented here is the inclusion of massive neutrinos and how they may affect the bound on t...
Discovering the QCD Axion with Black Holes and Gravitational Waves
Arvanitaki, Asimina; Huang, Xinlu
2014-01-01
Advanced LIGO will be the first experiment to detect gravitational waves. Through superradiance of stellar black holes, it may also be the first experiment to discover the QCD axion with decay constant above the GUT scale. When an axion's Compton wavelength is comparable to the size of a black hole, the axion binds to the black hole, forming a "gravitational atom." Through the superradiance process, the number of axions occupying the bound levels grows exponentially, extracting energy and angular momentum from the black hole. Axions transitioning between levels of the gravitational atom and axions annihilating to gravitons produce observable gravitational wave signals. The signals are long-lasting, monochromatic, and can be distinguished from ordinary astrophysical sources. We estimate O(1) transition events at aLIGO for an axion between 10^-11 and 10^-10 eV and up to 1000 annihilation events for an axion between 10^-13 and 10^-12 eV. Axion annihilations are particularly promising for much lighter masses at f...
Constraining axion dark matter with Big Bang Nucleosynthesis
International Nuclear Information System (INIS)
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 4He 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
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.
Detecting ultralight axion dark matter wind with laser interferometers
Aoki, Arata; Soda, Jiro
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 w...
Axion star collisions with Neutron stars and Fast Radio Bursts
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.
Coupled Boltzmann computation of mixed axion neutralino dark matter in the SUSY DFSZ axion model
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 ...
Mixed axion/neutralino dark matter in the SUSY DFSZ axion model
International Nuclear Information System (INIS)
We examine mixed axion/neutralino cold dark matter production in the SUSY DFSZ axion model where an axion superfield couples to Higgs superfields. We calculate a wide array of axino and saxion decay modes along with their decay temperatures, and thermal and non-thermal production rates. For a SUSY benchmark model with a standard underabundance (SUA) of Higgsino-like dark matter (DM), we find for the PQ scale fa∼<1012 GeV that the DM abundance is mainly comprised of axions as the saxion/axino decay occurs before the standard neutralino freeze-out and thus its abundance remains suppressed. For 1012∼
Search for sub-ev mass solar axions by the cern axion solar telescope with he-3 buffer gas
Çetin, Serkant Ali; CAST Collaboration
2011-01-01
The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using He-3 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 He-4. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eV less than or similar to m(a) less than or similar to 0.64 eV. From the absence of excess x rays when the magnet was pointing to ...
Minimal Models for Axion and Neutrino
Ahn, Y H
2015-01-01
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.
Minimal models for axion and neutrino
Ahn, Y. H.; Chun, Eung Jin
2016-01-01
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.
Naturalness of the invisible axion model
International Nuclear Information System (INIS)
We discuss the choice of parameters that is necessary to establish the enormous hierarchy between the doublet and singlet Higgs vacuum expectation values in the invisible axion model. We show that this choice is associated with an approximate symmetry of the theory, thus demonstrating that the hierarchy in this model is natural in the sense of 't Hooft. It is then shown that this choice also leads to the existence of Higgs particles with masses ∝MW, which is particularly relevant for invisible axion models featuring spontaneous CP-violation. We comment on how our conclusions are affected by the introduction of right-handed neutrinos with large Majorana masses within the context of the see-saw mechanism. (orig.)
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.
Relativistic axions from collapsing Bose stars
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.
Large volume axionic Swiss cheese inflation
International Nuclear Information System (INIS)
Continuing with the ideas of (Section 4 of) [A. Misra, P. Shukla, Moduli stabilization, large-volume dS minimum without anti-D3-branes, (non-)supersymmetric black hole attractors and two-parameter Swiss cheese Calabi-Yau's, (arXiv: 0707.0105 [hep-th]), Nucl. Phys. B, in press], after inclusion of perturbative and non-perturbative α' corrections to the Kaehler potential and (D1- and D3-) instanton generated superpotential, we show the possibility of slow roll axionic inflation in the large volume limit of Swiss cheese Calabi-Yau orientifold compactifications of type IIB string theory. We also include one- and two-loop corrections to the Kaehler potential but find the same to be subdominant to the (perturbative and non-perturbative) α' corrections. The NS-NS axions provide a flat direction for slow roll inflation to proceed from a saddle point to the nearest dS minimum
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...
Axion topological field theory of topological superconductors
Qi, Xiao-Liang; Witten, Edward; Zhang, Shou-Cheng
2012-01-01
Topological superconductors are gapped superconductors with gapless and topologically robust quasiparticles propagating on the boundary. In this paper, we present a topological field theory description of three-dimensional time-reversal invariant topological superconductors. In our theory the topological superconductor is characterized by a topological coupling between the electromagnetic field and the superconducting phase fluctuation, which has the same form as the coupling of "axions" with...
Conceptual design of the International Axion Observatory (IAXO)
International Nuclear Information System (INIS)
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 to solar axions produced by mechanisms mediated by the axion-electron coupling gae with sensitivity — for the first time — to values of gae 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, 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-ray optics, able to focus the signal photons into ∼ 0.2 cm2 spots that are imaged by ultra-low-background Micromegas x-ray detectors. The magnet is built into a structure with elevation and azimuth drives that will allow for solar tracking for ∼ 12 h each day
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...
Multiverse Dark Matter: SUSY or Axions
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 ...
Axion monodromy and the weak gravity conjecture
International Nuclear Information System (INIS)
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, Λ3∝mfMpl, 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.
Axion monodromy and the weak gravity conjecture
Hebecker, Arthur; Rompineve, Fabrizio; Westphal, Alexander
2016-04-01
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, Λ3 ˜ mf M 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.
Axion Monodromy and the Weak Gravity Conjecture
Hebecker, Arthur; Westphal, Alexander
2015-01-01
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, $\\Lambda^3 \\sim m f M_{pl}$, 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. I...
Future cosmological sensitivity for hot dark matter axions
Archidiacono, Maria; Hamann, Jan; Hannestad, Steen; Raffelt, Georg; Wong, Yvonne Y Y
2015-01-01
We study the potential of a future, large-volume photometric survey to constrain the axion mass $m_a$ in the hot dark matter limit. Future surveys such as Euclid will have significantly more constraining power than current observations for hot dark matter. Nonetheless, the lowest accessible axion masses are limited by the fact that axions lighter than $\\sim 0.15$ eV decouple before the QCD epoch, assumed here to occur at a temperature $T_{\\rm QCD} \\sim 170$ MeV; this leaves an axion population of such low density that its late-time cosmological impact is negligible. For larger axion masses, $m_a \\gtrsim 0.15$ eV, where axions remain in equilibrium until after the QCD phase transition, we find that a Euclid-like survey combined with Planck CMB data can detect $m_a$ at very high significance. Our conclusions are robust against assumptions about prior knowledge of the neutrino mass. Given that the proposed IAXO solar axion search is sensitive to $m_a\\lesssim 0.2$ eV, the axion mass range probed by cosmology is n...
Black Hole Mergers and the QCD Axion at Advanced LIGO
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 ...
Cosmological problems with multiple axion-like fields
International Nuclear Information System (INIS)
Incorporating the QCD axion and simultaneously satisfying current constraints on the dark matter density and isocurvature fluctuations requires non-minimal fine-tuning of inflationary parameters or the axion misalignment angle (or both) for Peccei-Quinn symmetry-breaking scales fa > 1012 GeV. To gauge the degree of tuning in models with many axion-like fields at similar symmetry-breaking scales and masses, as may occur in string theoretic models that include a QCD axion, we introduce a figure of merit F that measures the fractional volume of allowed parameter space: the product of the slow roll parameter ε and each of the axion misalignment angles, θ0. For a single axion, F∼−11 is needed to avoid conflict with observations. We show that the fine tuning of F becomes exponentially more extreme in the case of numerous axion-like fields. Anthropic arguments are insufficient to explain the fine tuning because the bulk of the anthropically allowed parameter space is observationally ruled out by limits on the cosmic microwave background isocurvature modes. Therefore, this tuning presents a challenge to the compatibility of string-theoretic models with light axions and inflationary cosmology
Cosmological problems with multiple axion-like fields
Mack, Katherine J.; Steinhardt, Paul J.
2011-05-01
Incorporating the QCD axion and simultaneously satisfying current constraints on the dark matter density and isocurvature fluctuations requires non-minimal fine-tuning of inflationary parameters or the axion misalignment angle (or both) for Peccei-Quinn symmetry-breaking scales fa > 1012 GeV. To gauge the degree of tuning in models with many axion-like fields at similar symmetry-breaking scales and masses, as may occur in string theoretic models that include a QCD axion, we introduce a figure of merit Script F that measures the fractional volume of allowed parameter space: the product of the slow roll parameter epsilon and each of the axion misalignment angles, θ0. For a single axion, Script Flesssim10-11 is needed to avoid conflict with observations. We show that the fine tuning of Script F becomes exponentially more extreme in the case of numerous axion-like fields. Anthropic arguments are insufficient to explain the fine tuning because the bulk of the anthropically allowed parameter space is observationally ruled out by limits on the cosmic microwave background isocurvature modes. Therefore, this tuning presents a challenge to the compatibility of string-theoretic models with light axions and inflationary cosmology.
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.
Axion Haloscopes with Toroidal Geometry at CAPP/IBS
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.
Detecting ultralight axion dark matter wind with laser interferometers
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.
Search for Solar Axions with the CCD Detector and X-ray Telescope at CAST Experiment
Rosu, Madalin-Mihai
2015-01-01
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 d...
Mixed axion/neutralino dark matter in the SUSY DFSZ axion model
Bae, Kyu Jung; Chun, Eung Jin
2013-01-01
We examine mixed axion/neutralino cold dark matter production in the SUSY DFSZ axion model where an axion superfield couples to Higgs superfields. We calculate a wide array of axino and saxion decay modes along with their decay temperatures, and thermal and non-thermal production rates. For a SUSY benchmark model with a standard underabundance (SUA) of Higgsino-like dark matter (DM), we find for the PQ scale f_a~ 10^{14} GeV, both neutralino dark matter and dark radiation are typically overproduced. For judicious parameter choices, these can be suppressed and the combined neutralino/axion abundance brought into accord with measured values. A SUSY benchmark model with a standard overabundance (SOA) of bino DM is also examined and typically remains excluded due at least to too great a neutralino DM abundance for f_a~ 10^{15} GeV and lower saxion masses, large entropy production from saxion decay can dilute all relics and the SOA model can be allowed by all constraints.
A New Target for Cosmic Axion Searches
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.
Electric and magnetic energy at axion haloscopes
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{\
Solitonic axion condensates modeling dark matter halos
Castañeda Valle, David; Mielke, Eckehard W.
2013-09-01
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.
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.
Design for a practical laboratory detector for solar axions
International Nuclear Information System (INIS)
We present a practical design for a detector sensitive to axions and other light particles with a two-photon interaction vertex. Such particles would be produced in the solar interior by Primakoff conversion of blackbody photons and could be detected by their reconversion into x rays (average energy about 4 keV) in a strong laboratory magnetic field. An existing large superconducting magnet would be suitable for this purpose. The transition rate is enhanced by filling the conversion region with a buffer gas (H2 or He). This induces an effective photon mass (plasma frequency) which can be adjusted to equal the axion mass being searched for. Axion-photon conversion is then coherent throughout the detector volume for all axion energies. Axions with mass in the range 0.1 eVapprox. < m/sub a/approx. <5 eV can be detected using gas pressures of 0.1--300 atm. Axions with the standard coupling strength to photons would give counting rates of 10/sup -5/--10 sec/sup -1/ over this mass range. The search would definitively test one of the only two regions of axion parameters not excluded by astrophysical constraints
Search for Solar Axions with the CAST-Experiment
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.
Hardimon, Michael O
2013-02-01
Confusions about the place of race in medicine result in part from a failure to recognize the plurality of race concepts. Recognition that the ordinary concept of race is not identical to the racialist concept of race makes it possible to ask whether there might be a legitimate place for the deployment of concepts of race in medical contexts. Two technical race concepts are considered. The concept of social race is the concept of a social group that is taken to be a racialist race. It is apt for use in examining and addressing the medical effects of discrimination. The populationist concept of race represents race as a kind of biological population. It makes it possible to frame the question whether biological race is a factor in disease susceptibility and drug responsiveness. It is apt for use in determining whether biological race is a medically significant category. PMID:23300217
Dilution of axion dark radiation by thermal inflation
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.
Searching for galactic axions through magnetized media: the QUAX proposal
Barbieri, R.; Braggio, C.; 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 a...
Constraining Axion Dark Matter with Big Bang Nucleosynthesis
Kfir Blum; Raffaele Tito D'Agnolo; Mariangela Lisanti; Benjamin R. Safdi
2014-01-01
We show that Big Bang Nucleosynthesis (BBN) significantly constrains axion-like dark matter. The axion acts like an oscillating QCD $\\theta$ 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 4He during BBN and is thus excluded. The BBN bound overlaps with much of the parameter space that would be covered by proposed searches for time-varying ...
Active galaxies may harbour wormholes if dark matter is axionic
Dimopoulos, Konstantinos
2016-01-01
AGN jets carry helical magnetic fields, which can affect dark matter if the latter is axionic. This preliminary study shows that the nature of the axionic condensate may change and instead of dark matter may behave more like exotic matter, which violates the null energy condition. If the central supermassive black hole of an active galaxy is laced with exotic matter then it may become a wormhole. In general, the presence of exotic matter may affect galaxy formation and galactic dynamics, so this possibility should not be ignored when considering axionic dark matter.
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.
Axion cyclotron emissivity of magnetized white dwarfs and neutron stars
Kachelriess, M.; Wilke, C.; Wunner, G.
1997-01-01
The energy loss rate of a magnetized electron gas emitting axions a due to the process $e^- \\to e^- +a$ is derived for arbitrary magnetic field strength B. Requiring that for a strongly magnetized neutron star the axion luminosity is smaller than the neutrino luminosity we obtain the bound $g_{ae}\\lsim 10^{-10}$ for the axion electron coupling constant. This limit is considerably weaker than the bound derived earlier by Borisov and Grishina using the same method. Applying a similar argument t...
Axion Emission from Red Giants and White Dwarfs
Altherr, Tanguy; Gaztelurrutia, T R
1994-01-01
Using thermal field theory methods, we recalculate axion emission from dense plasmas. We study in particular the Primakoff and the bremsstrahlung processes. The Primakoff rate is significantly suppressed at high densities, when the electrons become relativistic. However, the bound on the axion-photon coupling, $G<10^{-10}$ GeV, is unaffected, as it is constrained by the evolution of HB stars, which have low densities. In contradistinction, the same relativistic effects enhance the bremsstrahlung processes. From the red giants and white dwarfs evolution, we obtain a conservative bound on the axion-electron coupling, $g_{ae} < 2\\times 10^{-13}$.
Accelerating dark-matter axion searches with quantum measurement technology
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.
The cern axion solar telescope (CAST): an update
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.
The CERN axion solar telescope (CAST): an update
International Nuclear Information System (INIS)
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, g aγγ 3 x 10-10 GeV-1 for axion masses less than 5 x 10-2 eV
An argument that the dark matter is axions
Sikivie, P.
2012-01-01
An argument is presented that the dark matter is axions, at least in part. It has three steps. First, axions behave differently from the other forms of cold dark matter because they form a rethermalizing Bose-Einstein condensate (BEC). Second, there is a tool to distinguish axion BEC from the other dark matter candidates on the basis of observation, namely the study of the inner caustics of galactic halos. Third, the observational evidence for caustic rings of dark matter is consistent in eve...
Search for sub-eV mass solar axions by the CERN Axion Solar Telescope with 3He buffer gas.
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. PMID:22243149
D6-branes and axion monodromy inflation
Escobar, Dagoberto; Marchesano, Fernando; Regalado, Diego
2015-01-01
We develop new scenarios of large field inflation in type IIA string compactifications in which the key ingredient is a D6-brane that creates a potential for a B-field axion. The potential has the multi-branched structure typical of F-term axion monodromy models and, near its supersymmetric minima, it is described by a 4d supergravity model of chaotic inflation with a stabiliser field. The same statement applies to the D6-brane Wilson line, which can also be considered as an inflaton candidate. We analyse both cases in the context of type IIA moduli stabilisation, finding an effective potential for the inflaton system and a simple mechanism to lower the inflaton mass with respect to closed string moduli stabilised by fluxes. Finally, we compute the B-field potential for trans-Planckian field values by means of the DBI action. The effect of Planck suppressed corrections is a flattened potential which, in terms of the compactification parameters, interpolates between linear and quadratic inflation. This renders...
Axion dark matter from topological defects
Kawasaki, Masahiro; Sekiguchi, Toyokazu
2014-01-01
The cosmological scenario where the Peccei-Quinn symmetry is broken after inflation is investigated. In this scenario, topological defects such as strings and domain walls produce a large amount of axions, which contribute to the cold dark matter of the universe. The previous estimations of the cold dark matter abundance are updated and refined based on the field-theoretic simulations with improved grid sizes. The possible uncertainties originated in the numerical calculations are also discussed. It is found that axions can be responsible for the cold dark matter in the mass range $m_a=(0.9$-$1.4)\\times 10^{-4}\\mathrm{eV}$ for the models with the domain wall number $N_{\\rm DW}=1$, and $m_a\\approx\\mathcal{O}(10^{-4}$-$10^{-2})\\mathrm{eV}$ with a mild tuning of parameters for the models with $N_{\\rm DW}>1$. Such higher mass ranges can be probed in the future experimental studies.
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.
Non-gaussianity from axion monodromy inflation
International Nuclear Information System (INIS)
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 fNL ∼ 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
Vacuum statistics and stability in axionic landscapes
Masoumi, Ali; Vilenkin, Alexander
2016-03-01
We investigate vacuum statistics and stability in random axionic landscapes. For this purpose we developed an algorithm for a quick evaluation of the tunneling action, which in most cases is accurate within 10%. We find that stability of a vacuum is strongly correlated with its energy density, with lifetime rapidly growing as the energy density is decreased. On the other hand, the probability P(B) for a vacuum to have a tunneling action B greater than a given value declines as a slow power law in B. This is in sharp contrast with the studies of random quartic potentials, which found a fast exponential decline of P(B). Our results suggest that the total number of relatively stable vacua (say, with B>100) grows exponentially with the number of fields N and can get extremely large for Ngtrsim 100. The problem with this kind of model is that the stable vacua are concentrated near the absolute minimum of the potential, so the observed value of the cosmological constant cannot be explained without fine-tuning. To address this difficulty, we consider a modification of the model, where the axions acquire a quadratic mass term, due to their mixing with 4-form fields. This results in a larger landscape with a much broader distribution of vacuum energies. The number of relatively stable vacua in such models can still be extremely large.
Race and Gender Issues: Critical Race Feminism.
Wing, Adrien K.
1999-01-01
Introduces a new body of legal scholarship on race and gender: critical race feminism (CRF), examining critical legal studies, critical race theory, and feminism. Explains the term "global multiplicative identities" as it relates to CRF and concludes that CRF has the potential to benefit from more sustained interaction with human rights workers in…
Aspects of axion phenomenology in a slice of AdS5
International Nuclear Information System (INIS)
Motivated by multi-throat considerations, we study the phenomenological implications of a bulk axion in a slice of AdS5 with a large extra dimension: k ∼ 10-2 eV, kR∼>O(1). In particular, we compare axion physics with a warped geometry to axions in flat compactifications. As in flat compactification scenarios, we find that the mass of the axion can become independent from the underlying Peccei-Quinn scale. Surprisingly, we find that in warped extra dimensions the axion's invisibility, cosmological viability, and basic phenomenology remain essentially unaltered in comparison to axions in flat compactifications
Search of axions from a nuclear power reactor with a high-purity germanium detector
International Nuclear Information System (INIS)
This article reports the first study of possible emissions of axions from power reactors using Primakoff and Compton conversions as the detection mechanisms. The expected experimental signatures are mono-energetic lines produced by their Primakoff or Compton conversions at a high-purity germanium (HPGe) detector. No evidence of axion emissions were observed and constraints on axion couplings versus axion mass within the framework of invisible axion models were placed. This experimental approach provides a unique probe for axion mass at the keV-MeV range not accessible to the other techniques
Observational Constraints on Axions as Quintessence in String Theory
Gupta, Gaveshna; Sen, Anjan A
2011-01-01
We study the observational constraints for the axion models in string theory which can successfully act as quintessence. The evolution of the universe in this model is sensitive to the initial value of the axion field. This initial value of the axion field controls deviation of the cosmic evolution from the \\Lambda CDM behaviour. We use the recent Union2 Supernova Type Ia dataset as well as the data from BAO measurements, the WMAP measurement of the shift parameter and the $H(z)$ measurements. Using these data, the reconstructed equation of state of the axion field has extremely small deviation from the cosmological constant \\omega = -1 even at 2\\sigma confidence level. One interesting outcome of this analysis is that one can put bound on the SUSY breaking scale using cosmological measurements assuming the values of different string related parameters and vice versa.
Constraints on axion inflation from the weak gravity conjecture
International Nuclear Information System (INIS)
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 C4 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 C4 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
Prospects for solar axion searches with crystals via Bragg scattering
International Nuclear Information System (INIS)
A calculation of the expected signal due to Primakov coherent conversion of solar axions into photons via Bragg scattering in several solid-state detectors is presented and compared with present and future experimental sensitivities. The axion window ma > or approx. 0.03 eV (not accessible at present by other techniques) could be explored in the foreseeable future with crystal detectors to constrain the axion-photon coupling constant gaγγ below the latest bounds coming from helioseismology. On the contrary a positive signal in the sensitivity region of such devices would imply revisiting other more stringent astrophysical limits derived for the same range of the axion mass. The application of this technique to the COSME germanium detector which is taking data at the Canfranc Underground Laboratory leads to a 95% C.L. limit gaγγ ≤ 2.8 x 10-9 GeV-1
A scientist finally proves existence of elusive axion
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)
The electroweak axion, dark energy, inflation and baryonic matter
International Nuclear Information System (INIS)
In a previous paper [1], the standard model was generalized to include an electroweak axion which carries baryon plus lepton number, B + L. It was shown that such a model naturally gives the observed value of the dark energy, if the scale of explicit baryon number violation A was chosen to be of the order of the Planck mass. In this paper, we consider the effect of the modulus of the axion field. Such a field must condense in order to generate the standard Goldstone boson associated with the phase of the axion field. This condensation breaks baryon number. We argue that this modulus might be associated with inflation. If an additional B − L violating scalar is introduced with a mass similar to that of the modulus of the axion field, we argue that decays of particles associated with this field might generate an acceptable baryon asymmetry
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.
First results from the CERN Axion Solar Telescope (CAST)
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.
Non-thermal Axion Dark Radiation and Constraints
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.
First results from the CERN Axion Solar Telescope
International Nuclear Information System (INIS)
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 gaγ-10 GeV-1 at 95% C.L. for ma < or approx. 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses
Radio-loud magnetars as detectors for axions and axion-like particles
International Nuclear Information System (INIS)
We show that, by studying the arrival times of radio pulses from highly-magnetized transient beamed sources, it may be possible to detect light pseudo-scalar particles, such as axions and axion-like particles, whose existence could have considerable implications for the strong-CP problem of QCD as well as the dark matter problem in cosmology. Specifically, such light bosons may be detected with a much greater sensitivity, over a broad particle mass range, than is currently achievable by terrestrial experiments, and using indirect astrophysical considerations. The observable effect was discussed in Chelouche & Guendelman (2009), and is akin to the Stern-Gerlach experiment: the splitting of a photon beam naturally arises when finite coupling exists between the electro-magnetic field and the axion field. The splitting angle of the light beams linearly depends on the photon wavelength, the size of the magnetized region, and the magnetic field gradient in the transverse direction to the propagation direction of the photons. If radio emission in radio-loud magnetars is beamed and originates in regions with strong magnetic field gradients, then splitting of individual pulses may be detectable. We quantify the effect for a simplified model for magnetars, and search for radio beam splitting in the 2GHz radio light curves of the radio loud magnetar XTEJ1810-197. (author)
Amazing Race: Finding and Correctly Citing Credible Sources
Field-Springer, Kimberly; Striley, Katie Margavio
2016-01-01
The "Amazing Race" activity utilizes experiential learning by encouraging students to venture outside the classroom to collect and cite sources for an upcoming assignment. In the popular TV show, "Amazing Race," teams compete to complete tasks that take them around the world. Similarly, in this classroom activity, groups…
Axion Cosmology with a Stronger QCD in the Early Universe
Choi, Kiwoon; Kim, Hang Bae; Kim, Jihn E.
1996-01-01
We examine in the context of supersymmetric models whether the usual cosmological upper bound on the axion decay constant can be relaxed by assuming a period of stronger QCD in the early universe. By evaluating the axion potential in the early universe and also taking into account the dilaton potential energy, it is argued that a stronger QCD is not useful for raising up the bound.
Axion cosmology with a stronger QCD in the early universe
Energy Technology Data Exchange (ETDEWEB)
Choi Kiwoon [Korea Adv. Inst. of Sci. and Technol., Taejon (Korea, Republic of). Phys. Dept.; Kim, H.B. [Universidad Autonoma de Madrid (Spain). Dept. de Fisica Teorica; Kim, J.E. [Seoul National Univ. (Korea, Republic of). Dept. of Physics
1997-04-14
We examine in the context of supersymmetric models whether the usual cosmological upper bound on the axion decay constant can be relaxed by assuming a period of stronger QCD in the early universe. By evaluating the axion potential in the early universe and also taking into account the dilaton potential energy, it is argued that a stronger QCD is not useful for raising the bound. (orig.).
Emergent Majorana mass and axion couplings in superfluids
International Nuclear Information System (INIS)
Axions (in the general sense) may acquire qualitatively new couplings inside superfluids. Their conventional couplings to fermions, in empty space, involve purely imaginary masses; the new couplings involve emergent Majorana masses. A generalized concept of Majorana mass is proposed, which allows continuous interpolation between Majorana and Dirac fermions, and also extension to bosons. The possibility of weak links for axions, recently put forward, is analyzed and replaced with a non-local analogue. (fast track communication)
Class of Einstein-Maxwell-Dilaton-Axion Space-Times
Matos, Tonatiuh; Sanchez-Sanchez, Ruben; Wiederhold, Petra
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.
Primakoff effect: synchrotron and coulomb mechanisms of axion emission
International Nuclear Information System (INIS)
For the first time the axion radiative emission by alternating electromagnetic field Fa → γa is considered due to Primakoff effect. As a concrete supplement, the synchrotron and Coulomb mechanisms are discussed and in the last case the alternating field is formed at the infinite motion of a charge in a Coulomb center field. The estimates for contributions of these effects into axion luminosity of magnetic neutron stars and the Sun are determined
Primakoff effect: Synchrotron and Coulomb mechanisms of axion emission
International Nuclear Information System (INIS)
The Primakoff effect-induced radiative emission of axions by an alternating electromagnetic field, Fa → γa, is considered for the first time. The synchrotron mechanism and the Coulomb mechanism--in the latter case, the alternating field is formed when a charge executes an infinite motion in the field of a Coulomb center--are considered as specific examples. The contributions of these effects to the axion emissivity of magnetic neutron stars and of the Sun are estimated
The Superconducting Toroid for the New International AXion Observatory (IAXO)
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....
Searching for axions and ALPs from string theory
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 ...
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.
Natural Inflation with Multiple Sub-Planckian Axions
Choi, Kiwoon; Yun, Seokhoon
2014-01-01
We extend the Kim-Nilles-Peloso (KNP) alignment mechanism for natural inflation to models with N>2 axions, which obtains a super-Planckian effective axion decay constant f_{eff} >> M_{Pl} through an alignment of the anomaly coefficients of multiple axions having sub-Planckian fundamental decay constants f_0 O(100) as suggested by the recent BICEP2 results. We note that the KNP mechanism can be realized with the anomaly coefficients of O(1) if the number of axions N is large as N ln N > 2 ln (f_{eff}/f_0), in which case the effective decay constant can be exponentially enhanced as f_{eff}/f_0 ~ sqrt(N!) n^{N-1} for n denoting the typical size of the integer-valued anomaly coefficients. Comparing to the other multiple axion scenario, the N-flation scenario which requires N ~ f_{eff}^2/f_0^2, the KNP mechanism has a virtue of not invoking to a too large number of axions, although it requires a specific alignment of the anomaly coefficients, which can be achieved with a probability of O(f_0/f_{eff}) under a rand...
Axion helioscopes update: the status of CAST and IAXO
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...
A Solar Axion Search Using a Decommissioned LHC Test Magnet
Raffelt, G; Geralis, T; Lozza, V; Christensen, F E; Jakobsen, A C; Neff, S H; Dafni, T; Carmona martinez, J M; Giomataris, I; Krcmar, M; Vafeiadis, T; Bayirli, A; Luzon marco, G M; 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; Gracia garza, J; Ortega ruiz, I; Papaevangelou, T; Zioutas, K; Gardikiotis, 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...
Search for solar axions the CAST experiment at CERN
Beltran, B; Arsov, V; Aune, S; Autiero, D; Avignone, F T; Barth, K; Belov, A; Bräuninger, H; Carmona, J M; Cebrián, S; Chesi, Enrico Guido; Collar, J I; Creswick, R; Dafni, T; Davenport, M; Dilella, L; Eleftheriadis, C; Englhauser, J; Fanourakis, G K; Farach, H; Ferrer, E; Fischer, H; Franz, J; Friedrich, P; Geralis, T; Giomataris, Ioanis; Gninenko, S; Goloubev, N; Hartmann, R; 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; Ljubici, A; Lutz, Gerhard; 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, Pasquale Dario; Semertzidis, Y K; Stewart, L; Vieira, J D; Villar, J; Walckiers, L; Zachariadou, K; Zioutas, Konstantin; Beltran, Berta
2006-01-01
Hypothetical axion-like particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field they would be transformed into X-rays with energies of a few keV. The CAST experiment at CERN is using a decommissioned LHC magnet as an axion helioscope in order to search for these axion-like particles. The analysis of the 2003 data has shown no signal above the background, thus implying an upper limit to the axion-photon coupling < 1.16*10^{-10} GeV^{-1} at 95% CL for m_{a} <~ 0.02 eV. The stable operation of the experiment during 2004 data taking allow us to anticipate that this value will be improved. At the end of 2005 we expect to start with the so-called second phase of CAST, when the magnet pipes will be filled with a buffer gas so that the axion-photon coherence will be extended. In this way we will be able to search for axions with masses up to 1 eV.
First Axion Results from the XENON100 Experiment
Aprile, E.; Alfonsi, M.; Arisaka, K.; Arneodo, F.; Auger, M.; Balan, C.; Barrow, P.; Baudis, L.; Bauermeister, B.; Behrens, A.; Beltrame, P.; Bokeloh, K.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Cardoso, J.M.R.; Colijn, A.P.; Contreras, H.; Cussonneau, J.P.; Decowski, M.P.; Duchovni, E.; Fattori, S.; Ferella, A.D.; Fulgione, W.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L.W.; Grignon, C.; Gross, E.; Hampel, W.; Itay, R.; Kaether, F.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R.F.; Calloch, M. Le; Lellouch, D.; Levy, C.; Lindemann, S.; Lindner, M.; Lopes, J.A.M.; Lung, K.; Lyashenko, A.; Macmullin, S.; Marrodan Undagoitia, T.; Masbou, J.; Massoli, F.V.; Mayani Paras, D.; Melgarejo Fernandez, A. J.; Meng, Y.; Messina, M.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Oberlack, U.; Orrigo, S.E.A.; Pantic, E.; Persiani, R.; Piastra, F.; Pienaar, J.; Plante, G.; Priel, N.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; dos Santos, J. M. F.; Sartorelli, G.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Simgen, H.; Teymourian, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Vitells, O.; Wang, H.; Weber, M.; Weinheimer, C.
2014-01-01
We present the first results of searches for axions and axion-like-particles with the XENON100 experiment. The axion-electron coupling constant, $g_{Ae}$, has been tested by exploiting the axio-electric effect in liquid xenon. A profile likelihood analysis of 224.6 live days $\\times$ 34 kg exposure has shown no evidence for a signal. By rejecting $g_{Ae}$, larger than $7.7 \\times 10^{-12}$ (90% CL) in the solar axion search, we set the best limit to date on this coupling. In the frame of the DFSZ and KSVZ models, we exclude QCD axions heavier than 0.3 eV/c$^2$ and 80 eV/c$^2$, respectively. For axion-like-particles, under the assumption that they constitute the whole abundance of dark matter in our galaxy, we constrain $g_{Ae}$, to be lower than $1 \\times 10^{-12}$ (90% CL) for masses between 5 and 10 keV/c$^2$.
Conversion and Operation of CAST as a massive axion detector
Elias, Nuno; Bordalo, Paula
2010-01-01
The axion was postulated after an elegant solution proposed by R. Peccei and H. Quinn to solve the strong CP problem of Quantum Chromodynamics. The CAST experiment searches for axions created in the core of the Sun. It uses an LHC superconducting prototype magnet to trigger the axion conversion into detectable X-ray photons. During its First Phase, with the magnetic field region kept under vacuum, CAST searched with high sensitivity for axion masses up to 0.02 eV/c2, for higher values the conversion coherence is lost. This thesis reflects the work that allows CAST to extend its search up to axion masses of 1 eV/c2. To restore the lost coherence a buffer gas is introduced in the magnet cold bores, such that the photon arising from the Primakoff conversion acquires an effective mass. The axion mass can be effectively scanned by fine tuning the gas density. The conversion of the experiment required the study, design and construction of a complex gas handling system to deal with a rare helium isotope, 3He. It rep...
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.
3D Lumped LC Resonators as Low Mass Axion Haloscopes
McAllister, Ben T; Tobar, Michael E
2016-01-01
The axion is a hypothetical particle considered to be the most economical solution to the strong CP problem. It can also be formulated as a compelling component of dark matter. The haloscope, a leading axion detection scheme, relies on the conversion of galactic halo axions into real photons inside a resonant cavity structure in the presence of a static magnetic field, where the generated photon frequency corresponds to the mass of the axion. For maximum sensitivity it is key that the central frequency of the cavity mode structure coincides with the frequency of the generated photon. As the mass of the axion is unknown, it is necessary to perform searches over a wide range of frequencies. Currently there are substantial regions of the promising pre-inflationary low mass axion range without any viable proposals for experimental searches. We show that 3D resonant LC circuits with separated magnetic and electric fields, commonly known as re-entrant cavities, can be sensitive dark matter haloscopes in this region...
Antonio S. Mello
2006-01-01
This paper presents a model of team composition. Heterogeneous teams have a greater variety of information sources than homogeneous teams. If information and preferences can be expressed openly, heterogeneous teams reach better decisions. However, members of heterogeneous teams are more likely to diverge in their preferences with respect to courses of action, which is reflected in lower effort. Team leaders who are likely to be either uninformed or well informed about project payoffs prefer t...
Anisotropic plasmas from axion and dilaton deformations
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.
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.
Axion-photon Propagation in Magnetized Universe
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.
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.
Axion Searches in the Past, at Present, and in the Near Future
Battesti, R.; Beltran, B.; Davoudiasl, H.; M. Kuster(Technische Universität Darmstadt); Pugnat, P.; Rabadan, R.; Ringwald, A.; Spooner, N.; Zioutas, K.
2007-01-01
Theoretical axion models state that axions are very weakly interacting particles. In order to experimentally detect them, the use of colorful and inspired techniques becomes mandatory. There is a wide variety of experimental approaches that were developed during the last 30 years, most of them make use of the Primakoff effect, by which axions convert into photons in the presence of an electromagnetic field. We review the experimental techniques used to search for axions and will give an outlo...
Bezerra, V. B.; Klimchitskaya, G. L.; 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...
CP-Conservation in QCD and why only "invisible" Axions work
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.
Limits on heavy axion production from the reaction n(p,a)d
International Nuclear Information System (INIS)
A search has been made for the creation of shortlived axions in the isovector transition n(p,a)d decaying into e+e--pairs. The production of Peccei-Quinn axions can be excluded for 1.21 a -2 (90% CL). Limits on variant axion models are derived. (author)
Field-induced axion decay $a \\to e^+ e^-$ in KSVZ-model
Mikheev, N. V.; Ovchinnikov, O. S.; Vassilevskaya, L. A.
1997-01-01
The axion decay into electron-positron pair $a \\to e^+ e^-$ is studied in an external magnetic field in KSVZ-model where axions have only induced coupling to leptons. The axion lifetime in the field decreases with energy and field strength to seconds.
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.
Axion dark matter, solitons, and the cusp-core problem
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-...
Some theoretical and experimental aspects of axion physics
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...
Searching for axions and ALPs from string theory
International Nuclear Information System (INIS)
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, fa ∼ 109÷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 fa ∼ 1011÷12 GeV, the QCD axion can be the dominant part of dark matter and be detected in haloscopes exploiting microwave cavities. For fa ∼ 109÷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
New solar axion search in CAST with $^4$He filling
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...
Probing eV-scale axions with CAST
Arik, E; Autiero, D; Barth, K; Belov, A; Beltrán, B; Borghi, S; Bourlis, G; Boydag, F S; Bräuninger, H; Carmona, J M; Cebrián, S; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Di Lella, L; Dogan, O B; Eleftheriadis, C; Elias, N; Fanourakis, G K; Ferrer-Ribas, E; Fischer, H; Friedrich, P; Franz, J; Galán, J; Geralis, T; Giomataris, Yu; Gninenko, S; Gómez, H; Hartmann, R; Hasinoff, M; Heinsius, F H; Hikmet, I; Hoffmann, D H H; Irastorza, I G; Jacoby, J; Jakovcic, K; Kang, D; Königsmann, K C; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Lakic, B; Lasseur, C; Liolios, A; Ljubicic, A; Lutz, G; Luzón, G; Miller, D; Morales, J; Niinikoski, T; Nordt, A; Ortiz, A; Papaevangelou, T; Pivovaroff, M J; Placci, A; Raffelt, G; Riege, H; Rodríguez, A; Ruz, J; Sawidis, I; Semertzidis, Y; Serpico, P; Soufli, R; Stewart, L; van Bibber, K; Villar, J; Vogel, J; Walckiers, L; Zioutas, K
2009-01-01
We have searched for solar axions or other pseudoscalar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup. Whereas we previously have reported results from CAST with evacuated magnet bores (Phase I), setting limits on lower mass axions, here we report results from CAST where the magnet bores were filled with \\hefour gas (Phase II) of variable pressure. The introduction of gas generated a refractive photon mass $m_\\gamma$, thereby achieving the maximum possible conversion rate for those axion masses \\ma that match $m_\\gamma$. With 160 different pressure settings we have scanned \\ma up to about 0.4 eV, taking approximately 2 h of data for each setting. 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 $\\gag\\lesssim 2.17\\times 10^{-10} {\\rm GeV}^{-1}$ at 95% CL for $\\ma \\lesssim 0.4$ eV, the exact result depending on the pressure setting. The excluded parameter range covers realistic axio...
Latest results and prospects of the CERN Axion Solar Telescope
Energy Technology Data Exchange (ETDEWEB)
Irastorza, I G; Carmona, J M; Dafni, T; Galan, J [Instituto de Fisica Nuclear y Altas EnergIas, Universidad de Zaragoza, Zaragoza (Spain); Aune, S; Ferrer-Ribas, E [IRFU, Centre d' Etudes Nucleaires de Saclay (CEA-Saclay), Gif-sur-Yvette (France); Barth, K; Borghi, S; Davenport, M; Elias, N [European Organization for Nuclear Research (CERN), Geneve (Switzerland); Belov, A [Institute for Nuclear Research (INR), Russian Academy of Sciences, Moscow (Russian Federation); Braeuninger, H; Friedrich, P [Max-Planck-Institut fuer extraterrestrische Physik, Garching (Germany); Cantatore, G [Instituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste and Universita di Trieste, Trieste (Italy); Cetin, S A; Ezer, C [Dogus University, Istanbul (Turkey); Collar, J I [Enrico Fermi Institute and KICP, University of Chicago, Chicago, IL (United States); Eleftheriadis, C [Aristotle University of Thessaloniki, Thessaloniki (Greece); Fanourakis, G [National Center for Scientific Research ' Demokritos' , Athens (Greece); Gardikiotis, A, E-mail: Igor.Irastorza@cern.ch [Physics Department, University of Patras, Patras (Greece)
2011-08-10
The CERN Axion Solar Telescope (CAST) experiment searches for axions from the Sun converted into few keV photons via the inverse Primakoff effect in the high magnetic field of a superconducting Large Hadron Collider (LHC) decommissioned test magnet. After results obtained with vacuum in the magnet pipes (phase I of the experiment) as well as with {sup 4}He the collaboration is now immersed in the data taking with {sup 3}He, to be finished in 2011. The status of the experiment will be presented, including a preliminary exclusion plot of the first {sup 3}He data. CAST is currently sensitive to realistic QCD axion models at the sub-eV scale, and with axion-photon couplings down to the {approx} 2 x 10{sup -10} GeV{sup -1}, compatible with solar life limits. Future plans include revisiting vaccuum and {sup 4}He configurations with improved sensitivity, as well as possible additional search for non-standard signals from chamaleons, paraphotons or other WISPs. For the longer term, we study the feasibility of an altogether improved version of the axion helioscope concept, with a jump in sensitivity of about one order of magnitude in g{sub a}{gamma} beyond CAST.
Record Participation in the Relay Race!
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,...
Bridged Race Population Estimates
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...
Institute of Scientific and Technical Information of China (English)
无
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
The Race Race: Assimilation in America
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…
Search for energetic cosmic axions utilizing terrestrial/celestial magnetic fields
Zioutas, K.; Thompson, D J; E. A. Paschos
1998-01-01
Orbiting $\\gamma$-detectors combined with the magnetic field of the Earth or the Sun can work parasitically as cosmic axion telescopes. The relatively short field lengths allow the axion-to-photon conversion to be coherent for $m_{axion} \\sim 10^{-4}$ eV, if the axion kinetic energy is above $\\sim 500$ keV (Earth's field), or, $\\sim 50$ MeV (Sun's field), allowing thus to search for axions from $e^+e^-$ annihilations, from supernova explosions, etc. With a detector angular resolution of $\\sim...
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.
Ruz, J; García Irastorza, I
CAST (CERN Axion Solar Telescope) is a helioscope looking for axions coming from the solar core to the Earth. The experiment, located at CERN, is based on the Primakoff effect and uses a magnetic field of 9 Tesla provided by a decommissioned LHC magnet. CAST is able to follow the Sun during sunrise and sunset and, therefore, different X-ray detectors are mounted on both ends of the magnet waiting for a photon from axion-to-photon conversion due to the Primakoff effect. During its First Phase, which concluded in 2004, the TPC detector of CAST looked for axions with masses up to 0.02 eV. By using a Helium-4 buffer gas, CAST's TPC detector has been able to re-establish the coherence needed to scan for axions with masses up to 0.39 eV, technique that allows CAST to look into the theoretical regions for axions.
Templeton, Alan R.
2013-01-01
Races may exist in humans in a cultural sense, but biological concepts of race are needed to access their reality in a non-species-specific manner and to see if cultural categories correspond to biological categories within humans. Modern biological concepts of race can be implemented objectively with molecular genetic data through hypothesis-testing. Genetic data sets are used to see if biological races exist in humans and in our closest evolutionary relative, the chimpanzee. Using the two m...
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.
New Bounds for Axions and Axion-Like Particles with keV-GeV Masses
Millea, Marius; Fields, Brian
2015-01-01
We give updated constraints on hypothetical light bosons with a two-photon coupling such as axions or axion-like particles (ALPs). We focus on masses and lifetimes where decays happen near big bang nucleosynthesis (BBN), thus altering the baryon-to-photon ratio and number of relativistic degrees of freedom between the BBN epoch and the cosmic microwave background (CMB) last scattering epoch, in particular such that $N_{\\rm eff}^{\\rm CMB} 3\\sigma$ by the combination of CMB+D/H measurements if only ALPs and three thermalized neutrino species contribute to $N_{\\rm eff}$. The bound relaxes if there are additional light degrees of freedom present which, in this scenario, have their contribution limited to $\\Delta N_{\\rm eff}=1.1\\pm0.3$. We give forecasts showing that a number of experiments are expected to reach the sensitivity needed to further test this region, such as Stage-IV CMB and SUPER-KEKB, the latter a direct test insensitive to any extra degrees of freedom.
Buff Thermo°CoolTM Team On Top
Institute of Scientific and Technical Information of China (English)
无
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
Cosmology with axionic-quintessence coupled with dark matter
International Nuclear Information System (INIS)
We study the possibility of explaining the late time acceleration with an axion field which is coupled with the dark matter sector of the energy budget of the Universe. The axion field arises from the Ramond–Ramond sector of the Type-IIB string theory. We study the background evolution of the Universe as well as the growth of the matter perturbation in the linear regime. We subsequently use the observational data from Sn-Ia, BAO measurements, measurements of the Hubble parameter as well as the observational data for the growth of the matter perturbation to constrain our model. Our results show that coupled axion models are allowed to have larger deviation from the cosmological constant by the present observational data. Communicated by P R L V Moniz (paper)
CrossRef The CERN Axion Solar Telescope
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.
Searching for galactic axions through magnetized media: the QUAX proposal
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.
Leptogenesis from left-handed neutrino production during axion inflation
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.
Leptogenesis from Left-Handed Neutrino Production during Axion Inflation
Adshead, Peter; Sfakianakis, Evangelos I.
2016-03-01
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 S U (2 )L sphaleron into a net baryon number.
Invisible axion search in 139La M1 transition
International Nuclear Information System (INIS)
A search for invisible axions is carried out by looking for invisible M1 transitions in 139La(5/2+→7/2+) with a transition energy of 166 keV. A limit to the branching ratio of axion emission to that of γ emission is obtained to be Γa/Γγ-6 at the 95% confidence level. Hadronic axions heavier than 26.7 keV are excluded by this upper limit. It is also concluded that the branching ratio of the second forbidden electron capture decay of 139Ce into the ground state of 139La(7/2+) is less than 9.7x10-7 at the 95% confidence level
Couplings between QCD axion and photon from string compactification
Kim, Jihn E
2016-01-01
The QCD axion couplings of various invisible axion models are presented. In particular, the exact global symmetry U(1)$_{\\rm PQ}$ 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, $c_{a\\gamma\\gamma}\\ge \\frac83-c_{a\\gamma\\gamma}^{\\rm ch\\,br}$ where $c_{a\\gamma\\gamma}^{\\rm ch\\,br}\\simeq 2$. However, this bound is not applicable in approximate U(1)$_{\\rm PQ}$ models with sufficiently suppressed U(1)$_{\\rm PQ}$-breaking superpotential terms. We also present a simple method to obtain $c_{a\\gamma\\gamma}^0$ which is the value obtained above the electroweak scale.
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.
Effects of axions on Nucleosynthesis in massive stars
Aoyama, Shohei
2015-01-01
We investigate the effect of the axion cooling on the nucleosynthesis in a massive star with $16M_{\\odot}$ by standard stellar evolution calculation. We find that the axion cooling suppresses the nuclear reactions in carbon, oxygen and silicon burning phases because of the extraction of the energy. As a result, larger amounts of the already synthesized neon and magnesium remain without being consumed to produce further heavier elements. Even in the case with the axion-photon coupling constant $g_{a\\gamma}= 10^{-11}$ GeV$^{-1}$, which is six times smaller than the current upper limit, the amount of neon and magnesium that remain just before the core-collapse supernova explosion is considerably larger than the standard value. This implies that we could give a more stringent constraint on $g_{a\\gamma}$ from the nucleosynthesis of heavy elements in massive stars.
Quality of the Peccei-Quinn symmetry in the Aligned QCD Axion and Cosmological Implications
Higaki, Tetsutaro; Kitajima, Naoya; Takahashi, Fuminobu
2016-01-01
We show that the required high quality of the Peccei-Quinn symmetry can be naturally explained in the aligned QCD axion models where the QCD axion arises from multiple axions with decay constants much smaller than the axion window, e.g., around the weak scale. Even in the presence of general Planck-suppressed Peccei-Quinn symmetry breaking operators, the effective strong CP phase remains sufficiently small in contrast to the standard axion models without the alignment. The QCD axion potential has small or large modulations due to the symmetry breaking operators, which can significantly affect the axion cosmology. When the axions are trapped in different minima, domain walls appear and their scaling behavior suppresses the axion isocurvature perturbations at super-horizon scales. In extreme cases the QCD axion mass can be much heavier than in the conventional scenario, and becomes unstable in a cosmological time scale. Our scenario predicts many axions and saxions coupled to gluons, and they may be searched fo...
Widening the Axion Window via Kinetic and Stückelberg Mixings.
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. PMID:26565455
On the 3-form formulation of axion potentials from D-brane instantons
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.
Can Gravitational Instantons Really Constrain Axion Inflation?
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...
Axion-photon propagation in magnetized universe
Wang, Chen; Lai, Dong
2016-06-01
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%. This result can affect previous constraints on ALP properties based on ALP-photon propagation in intergalactic magnetic fields, such as TeV photons from distant Active Galactic Nucleus.
Vacuum statistics and stability in axionic landscapes
Masoumi, Ali
2016-01-01
We investigate vacuum statistics and stability in random axionic landscapes. For this purpose we developed an algorithm for a quick evaluation of the tunneling action, which in most cases is accurate within 10%. We find that stability of a vacuum is strongly correlated with its energy density, with lifetime rapidly growing as the energy density is decreased. The probability $P(B)$ for a vacuum to have a tunneling action $B$ greater than a given value declines as a slow power law in $B$. This is in sharp contrast with the studies of random quartic potentials, which found a fast exponential decline of $P(B)$. Our results suggest that the total number of relatively stable vacua (say, with $B> 100$) grows exponentially with the number of fields $N$ and can get extremely large for $N\\gtrsim 100$. The problem with this kind of model is that the stable vacua are concentrated near the absolute minimum of the potential, so the observed value of the cosmological constant cannot be explained without fine-tuning. To addr...
CERN Relay Race: information for drivers
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.
Neutrino and axion hot dark matter bounds after WMAP-7
International Nuclear Information System (INIS)
We update cosmological hot dark matter constraints on neutrinos and hadronic axions. Our most restrictive limits use 7-year data from the Wilkinson Microwave Anisotropy Probe for the cosmic microwave background anisotropies, the halo power spectrum (HPS) from the 7th data release of the Sloan Digital Sky Survey, and the Hubble constant from Hubble Space Telescope observations. We find 95% CL upper limits of Σmν a ν = 0), and Σmν a ν a constraints. This difference can be traced to the fact that for a given hot dark matter fraction axions are much more massive than neutrinos
Cavity design for high-frequency axion dark matter detectors
Stern, I; Hoskins, J; Sikivie, P; Sullivan, N S; Tanner, D B; Carosi, G; van Bibber, K
2016-01-01
In an effort to extend the usefulness of microwave cavity detectors to higher axion masses, above ~8 $\\mu$eV (~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.
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 being...... energy physics frontier. On the other hand IAXO,the fourth generation axion helioscope, aims to improve CAST’s performance in terms of axionphotoncoupling by 1-1.5 orders of magnitude. The details of the project building a dedicatedmagnet, optics and X-ray detectors are given....
Gravity and axions from a random UV QFT
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.
Modulation and diurnal variation in axionic dark matter searches
Semertzidis, Y
2015-01-01
In the present work we study possible time dependent effects in Axion Dark Matter searches employing resonant cavities. We find that the width of the resonance, which depends on the axion mean square velocity in the local frame, will show an annual variation due to the motion of the Earth around the sun (modulation). Furthermore, if the experiments become directional, employing suitable resonant cavities, one expects large asymmetries in the observed widths relative to the sun's direction of motion. Due to the rotation of the Earth around its axis, these asymmetries will manifest themselves as a diurnal variation in the observed width.
Axion-like particle searches with sub-THz photons
Capparelli, L; Ferretti, J; Giazotto, F; Polosa, A D; Spagnolo, P
2015-01-01
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.
Towards axionic Starobinsky-like inflation in string theory
International Nuclear Information System (INIS)
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
Towards universal axion inflation and reheating in string theory
International Nuclear Information System (INIS)
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
Cosmic D-strings as Axionic D-term Strings
Blanco-Pillado, Jose J.; Dvali, Gia; Redi, Michele(INFN — Sezione di Firenze, Via G. Sansone, 1, I-50019, Sesto Fiorentino, Italy)
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 pa...
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.
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.
Latest results and prospects of the CERN Axion Solar Telescope
2011-01-01
The CERN Axion Solar Telescope (CAST) experiment searches for axions from the Sun converted into few keV photons via the inverse Primakoff effect in the high magnetic field of a superconducting Large Hadron Collider (LHC) decommissioned test magnet. After results obtained with vacuum in the magnet pipes (phase I of the experiment) as well as with 4He the collaboration is now immersed in the data taking with 3He, to be finished in 2011. The status of the experiment will be presented, including...
Axion-like particle searches with sub-THz photons
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.
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...
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...
ATLAS participation to the 36th Annual CERN Relay Race
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...
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…
Search for energetic cosmic axions utilizing terrestrial/celestial magnetic fields
Zioutas, Konstantin; Paschos, E A
1998-01-01
Orbiting $\\gamma$-detectors combined with the magnetic field of the Earth or the Sun can work parasitically as cosmic axion telescopes. The relatively short field lengths allow the axion-to-photon conversion to be coherent for $m_{axion} \\sim 10^{-4}$ eV, if the axion kinetic energy is above $\\sim 500$ keV (Earth's field), or, $\\sim 50$ MeV (Sun's field), allowing thus to search for axions from $e^+e^-$ annihilations, from supernova explosions, etc. With a detector angular resolution of $\\sim 1^o$, a more efficient sky survey for energetic cosmic axions passing {\\it through the Sun} can be performed. Axions or other axion-like particles might be created by the interaction of the cosmic radiation with the Sun, similarly to the axion searches in accelerator beam dump experiments; the enormous cosmic energy combined with the built-in coherent Primakoff effect might provide a sensitive detection scheme, being out of reach with accelerators. The axion signal will be an excess in $\\gamma$-rays coming either from a ...
Templeton, Alan R
2013-09-01
Races may exist in humans in a cultural sense, but biological concepts of race are needed to access their reality in a non-species-specific manner and to see if cultural categories correspond to biological categories within humans. Modern biological concepts of race can be implemented objectively with molecular genetic data through hypothesis-testing. Genetic data sets are used to see if biological races exist in humans and in our closest evolutionary relative, the chimpanzee. Using the two most commonly used biological concepts of race, chimpanzees are indeed subdivided into races but humans are not. Adaptive traits, such as skin color, have frequently been used to define races in humans, but such adaptive traits reflect the underlying environmental factor to which they are adaptive and not overall genetic differentiation, and different adaptive traits define discordant groups. There are no objective criteria for choosing one adaptive trait over another to define race. As a consequence, adaptive traits do not define races in humans. Much of the recent scientific literature on human evolution portrays human populations as separate branches on an evolutionary tree. A tree-like structure among humans has been falsified whenever tested, so this practice is scientifically indefensible. It is also socially irresponsible as these pictorial representations of human evolution have more impact on the general public than nuanced phrases in the text of a scientific paper. Humans have much genetic diversity, but the vast majority of this diversity reflects individual uniqueness and not race. PMID:23684745
A Visible QCD Axion from an Enlarged Color Group
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...
Large-scale search for dark-matter axions
Energy Technology Data Exchange (ETDEWEB)
Kinion, D; van Bibber, K
2000-08-30
We review the status of two ongoing large-scale searches for axions which may constitute the dark matter of our Milky Way halo. The experiments are based on the microwave cavity technique proposed by Sikivie, and marks a ''second-generation'' to the original experiments performed by the Rochester-Brookhaven-Fermilab collaboration, and the University of Florida group.
Active galactic nuclei shed light on axion-like-particles
Energy Technology Data Exchange (ETDEWEB)
Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Davis, Anne-Christine [Centre for Mathematical Sciences, Cambridge (United Kingdom). Dept. of Applied Mathematics and Theoretical Physics; Shaw, Douglas J. [London Univ. (United Kingdom). Astronomy Unit, School of Mathematical Sciences
2009-02-15
We demonstrate that the scatter in the luminosity relations of astrophysical objects can be used to search for axion-like-particles (ALPs). This analysis is applied to observations of active galactic nuclei, where we find evidence highly suggestive of the existence of a very light ALP. (orig.)
Search for Solar Axions with the CDMS-II Experiment
Bruch, T
2008-01-01
The CDMS-II experiment operates 19 germanium detectors with a mass of 250g each in a very low background environment. Originally designed for the search for Dark Matter the experiment can also detect solar axions by Primakoff conversion to photons. The Bragg condition for X-ray momentum transfer in a crystal allows for coherent amplification of the Primakoff process. Since the orientation of the crystal lattice with respect to the Sun changes with daytime an unique pattern in time and energy of solar axion conversions is expected. The low background ~1.5 counts/kg/day/keV and knowledge of the exact orientation of all three crystal axes with respect to the Sun make the CDMS-II experiment very sensitive to solar axions. In contrast to helioscopes, the high mass region < 1 keV can also be probed effectively. The alternating orientations of the individual crystals in the experimental setup provide different patterns of solar axion conversion, making a false positive result extremely unlikely. The result of an ...
A visible QCD axion from an enlarged color group
Gherghetta, Tony; Nagata, Natsumi; Shifman, Mikhail
2016-06-01
We consider the possibility of an enlarged QCD color group, SU (3 +N') spontaneously broken to SU (3 )c×SU (N') with extra vectorlike 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 C P problem for both gauge groups. However, the axion mass now receives a new nonperturbative contribution from the SU (N') 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 is ˜TeV and the PQ-breaking scale is ˜10 TeV . This predicts vectorlike quarks and a PQ scalar resonance in the multi-TeV range, with the possibility that dark matter is an SU (N') baryon.
Axionic extension of the Einstein-aether theory
Balakin, Alexander B.
2016-07-01
We extend the Einstein-aether theory to take into account the interaction between a pseudoscalar field, which describes the axionic dark matter, and a timelike 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 in the Lagrangian of interactions all possible terms up to the second order in the covariant derivative. The 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 a dynamic unit vector field and axionic dark matter is considered as an application of the established theory; new exact solutions are discussed, which describe models with big rip, pseudo-rip, and de Sitter-type asymptotic behavior.
Axionic extension of the Einstein-aether theory
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 ...
Minkowski 3-forms, Flux String Vacua, Axion Stability and Naturalness
Bielleman, Sjoerd; Valenzuela, Irene
2015-01-01
We discuss the role of Minkowski 3-forms in flux string vacua. In these vacua all internal closed string fluxes are in one to one correspondence with quantized Minkowski 4-forms. By performing a dimensional reduction of the $D=10$ Type II supergravity actions we find that the 4-forms act as auxiliary fields of the Kahler and complex structure moduli in the effective action. We show that all the RR and NS axion dependence of the flux scalar potential appears through the said 4-forms. Gauge invariance of these forms then severely restricts the structure of the axion scalar potentials. Combined with duality symmetries it suggests that all perturbative corrections to the leading axion scalar potential $V_0$ should appear as an expansion in powers of $V_0$ itself. These facts could have an important effect e.g. on the inflaton models based on F-term axion monodromy. We also suggest that the involved multi-branched structure of string vacua provides for a new way to maintain interacting scalar masses stable against...
Evolving Pacing Strategies for Team Pursuit Track Cycling
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.
DEFF Research Database (Denmark)
This book presents new empirical studies of social difference in the Nordic welfare states, in order to advance novel theoretical perspectives on the everyday practices and macro-politics of race and gender in multi-ethnic societies. With attention to the specific political and cultural landscapes...... 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...
CERN Relay Race: a great success!
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 ...
The success of the 45th CERN Relay Race
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.)
Simulation of an electric racing car using energetic macroscopic representation
Montesinos Miracle, Daniel; Fontán Tebar, Cristian; Vidal Salvia, Humbert
2014-01-01
Formula Student is a university competition around the world where students are required to design, construct and compete with a race car in static and dynamic tests. Since few years ago, this competition has moved to electric propulsion. ETSEIB Motorsport Team at Barcelona, Spain has develop an electric race car and this paper presents the EMR and IBC developed for that in order to analyze the car and further improve the braking and traction system.
QCD Axion as a Bridge Between String Theory and Flavor Physics
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.
Solving the Strong CP Problem with High-Colour Quarks and Composite Axion
Kobakhidze, Archil
2016-01-01
I propose a new axionic solution to the strong CP problem which involves a hypothetical vector-like quark(s) in a high-colour representation of the conventional QCD. There are two distinct scenarios. If the current mass of the exotic quark is zero, the strong CP phase can be trivially rotated away. The high-colour quark is `hidden' in various bounds states, the lightest being the composite axion field, with properties similar to the standard invisible axion. If the high-colour quark acquire a non-zero current mass due to the spontaneous chiral symmetry breaking, the composite axion can be heavy, while the strong CP phase is still cancelling out in the vacuum. The phenomenology and cosmological implications of the heavy composite axion differs drastically from the standard invisible axion.
Limits on axion and light Higgs boson production in Υ(1S) decays
International Nuclear Information System (INIS)
We have searched for axion and light Higgs boson production in the channel Υ(1S)→{a0 or h0}+γ, where the non-interacting axion a0 and the Higgs boson h0 do not decay in the detector. We find no evidence for an axion and give an upper limit, Br(Υ(1S)→a0γ)-5 (90% C.L.) for long-lived axions. Combining our limit with the previous axion search in J/ψ decays, we are able to rule out the standard light axion. Our Υ(1S) data also rule out a Higgs boson with mass mh<86 MeV. (orig.)
QCD axion as a bridge between string theory and flavor physics
Ahn, Y. H.
2016-04-01
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 C P 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.
130GeV gamma-ray line through axion conversion
Yamanaka, Masato; Ioka, Kunihito; Nojiri, Mihoko M
2013-01-01
We apply the axion-photon conversion mechanism to the 130GeV gamma-ray line observed by Fermi satellite. Mono-energetic axions or axion-like particles (ALPs) can be produced through annihilation or decay processes of dark matter. Then the axion converts to the gamma-ray in Galactic magnetic fields along its flight to the Earth, which can explain the observations. This mechanism suppresses productions of any continuum components of gamma-rays and cosmic-ray anti-protons, which is severe constraints to the models trying to explain the observation from unknown new particles. In our mechanism, the gamma-ray spatial distribution depends on both the dark matter profile and the magnetic field configuration, which will be tested by future gamma-ray observations, e.g., through HESS II, CTA, GAMMA-400. As an example, we discuss possible scenarios for the 130GeV axion emissions in supersymmetric axion models.
Axion electrodynamics and dark matter fingerprints in the terrestrial magnetic and electric fields
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.
Thermal production of not so invisible axions in the early universe
Energy Technology Data Exchange (ETDEWEB)
Turner, M.S.
1986-10-01
We find that for Peccei-Quinn symmetry-breaking scales less than or equal to 2 x 10/sup 8/ GeV (corresponding to axion masses greater than or equal to 3 x 10/sup -2/eV) thermal production of axions in the early Universe (via the Primakoff and photoproduction processes) dominates coherent production by a factor of about 1200 (m/sub a//eV)/sup 2.175/. The photon luminosity from the decays of these relic axions leads to a model-independent upper limit to the axion mass of order 2 to 5eV. If the axion mass saturates this bound, relic axion decays may well be detectable. 14 refs., 3 figs.
Bounds on QCD axion mass and primordial magnetic field from CMB $\\mu$-distortion
Ejlli, Damian
2014-01-01
Oscillation of CMB photons into axions can cause CMB spectral distortion in presence of large scale magnetic fields. With COBE limit on $\\mu$ parameter and homogeneous magnetic field strength $B\\lesssim 3.2$ nG at horizon scale, constraint on axion mass is found to be $4.8\\times 10^{-5}$ eV $\\lesssim m_a$ for the KSVZ axion model. On the other hand using experimental limit on axion mass $3.5\\times 10^{-6}$ eV $\\lesssim m_a$ from ADMX experiment together with COBE $\\mu$ bound, is found $B\\lesssim 53$ nG (KSVZ axion model) and $B\\lesssim 141$ nG (DFSZ axion model) for homogeneous magnetic field with coherence length at present $\\lambda_B\\sim 1.3$ Mpc. Limits on $B$ and $m_a$ for PIXIE/PRISM expected bound on $\\mu$ are derived.
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 ...
CERN runners on the podium for the Escalade race
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 ...
Future Directions in the Microwave Cavity Search for Dark Matter Axions
Shokair, T. M.; Root, J.; van Bibber, K. A.; Brubaker, B.; Gurevich, Y. V.; Cahn, S. B.; Lamoreaux, S. K.; Anil, M. A.; Lehnert, K. W.; Mitchell, B K; Reed, A; Carosi, G.
2014-01-01
The axion is a light pseudoscalar particle which suppresses CP-violating effects in strong interactions and also happens to be an excellent dark matter candidate. Axions constituting the dark matter halo of our galaxy may be detected by their resonant conversion to photons in a microwave cavity permeated by a magnetic field. The current generation of the microwave cavity experiment has demonstrated sensitivity to plausible axion models, and upgrades in progress should achieve the sensitivity ...
Axion Inflation with an SU(2) Gauge Field: Detectable Chiral Gravity Waves
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\
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.
Chiral anomaly, Charge Density Waves, and Axion Strings from Weyl Semimetals
Wang, Zhong; Zhang, Shou-Cheng
2012-01-01
We study dynamical instability and chiral symmetry breaking in three dimensional Weyl semimetals, which turns Weyl semimetals into "axion insulators". Charge density waves (CDW) is found to be the natural consequence of the chiral symmetry breaking. The phase mode of this charge density wave state is identified as the axion, which couples to electromagnetic field in the topological $\\theta{\\bf E}\\cdot{\\bf B}$ term. One of our main results is that the "axion strings" can be realized as the (sc...
CERN Relay Race: No records broken in a bumper year
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...
Experimental Search for Solar Axions via Coherent Primakoff Conversion in a Germanium Spectrometer
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.
5th Patras workshop on axions, WIMPs and WISPs (PATRAS 2009). Proceedings
International Nuclear Information System (INIS)
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)
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)
The International Axion Observatory IAXO. Letter of Intent to the CERN SPS committee
Irastorza, Igor G
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...
Axion Searches in the Past, at Present, and in the Near Future
Battesti, R; Davoudiasl, H; Kuster, M; Pugnat, P; Rabadan, R; Ringwald, A; Spooner, N J C; Zioutas, K
2008-01-01
Theoretical axion models state that axions are very weakly interacting particles. In order to experimentally detect them, the use of colorful and inspired techniques becomes mandatory. There is a wide variety of experimental approaches that were developed during the last 30 years, most of them make use of the Primakoff effect, by which axions convert into photons in the presence of an electromagnetic field. We review the experimental techniques used to search for axions and will give an outlook on experiments planned for the near future.
Conversion of Dark matter axions to photons in magnetospheres of neutron stars
Pshirkov, M. S.; Popov, S. B.
2007-01-01
We propose a new method to detect observational appearance of Dark Matter axions. The method utilizes observations of neutron stars (NSs) in radio. It is based on the conversion of axions to photons in strong magnetic fields of NSs (Primakoff effect). Whether the conversion takes place, the radio spectrum of the object would have a very distinctive feature -- a narrow spike at a frequency corresponding to the rest mass of the axion. For example, if the coupling constant of the photon-axion in...
Experimental Search for Solar Axions via Coherent Primakoff Conversion in a Germanium Spectrometer
International Nuclear Information System (INIS)
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 when axions are incident at a Bragg angle with a crystalline plane. The analysis of 1.94kgyr of data from the 1kg DEMOS detector in Sierra Grande, Argentina, yields a new laboratory bound by an axion-photon coupling of gaγγ-9 GeV-1 , independent of axion mass up to ∼1 keV . copyright 1998 The American Physical Society
Axion decay constants at special points in type II string theory
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.
McAfee, Myosha
2014-01-01
In this research article, Myosha McAfee presents findings from her grounded theory and microethnographical study of math instruction in a racially and socioeconomically diverse public school. Her analysis puts forth a new theory-the kinesiology of race-which conceptualizes race as a verb rather than a noun. It centrally considers how racial…
Fischer, Bill; Boynton, Andy
2005-01-01
Managing a traditional team seems pretty straightforward: Gather up whoever's available, give them time and space to do their jobs, and make sure they all play nicely together. But these teams produce results that are often as unremarkable as the teams themselves. When big change and high performance are required, a virtuoso team is far more likely to deliver outstanding and innovative results. Virtuoso teams are fundamentally different from the garden-variety work groups that most organizations form to pursue more modest goals. They comprise the top experts in their particular fields, are specially convened for ambitious projects, work with frenetic rhythm, and emanate a discernible energy. Not surprisingly, however, the superstars who make up these teams are renowned for being elitist, temperamental, egocentric, and difficult to work with. As a result, many managers fear that if they force such people to interact on a high-stakes project, the group just might implode. In this article, Bill Fischer and Andy Boynton put the inner workings of highly successful virtuoso teams on full display through three examples: the creative group behind West Side Story, the team of writers for Sid Caesar's 1950s-era television hit Your Show of Shows, and the high-powered technologists who averted an investor-relations crisis for Norsk Hydro, the Norwegian energy giant. Each of these teams accomplished enormous goals and changed their businesses, their customers, even their industries. And they did so by breaking all the conventional rules of collaboration--from the way they recruited the best members to the way they enforced their unusual processes, and from the high expectations they held to the exceptional results they produced. PMID:16028822
A SQUID-Based RF Cavity Search for Dark Matter Axions
Hotz, Michael T.
The axion is a hypothetical elementary particle resulting from a solution to the "Strong-CP" problem. This serious problem in the standard model of particle physics is manifested as a 1010 discrepancy between the measured upper limit and the calculated value of the neutron's electric dipole moment. Furthermore, a light (~mueV) axion is an ideal dark matter candidate: axions would have been copiously produced during the Big Bang and would be the primary component of the dark matter in the universe. The resolution of the Strong-CP problem and the discovery of the composition of dark matter are two of the most pressing problems in physics. The observation of a light, dark-matter axion would resolve both of these problems. The Axion Dark Matter eXperiment (ADMX) is the most sensitive search for dark-matter axions. Axions in our Milky Way Galaxy may scatter off a magnetic field and convert into microwave photons. ADMX consists of a tunable high-Q RF cavity within the bore of a large, 8.5 Tesla superconducting solenoidal magnet. When the cavity's resonant frequency matches the axion's total energy, the probability of axion-to-photon conversion is enhanced. The cavity's narrow bandwidth requires ADMX to slowly scan possible axion masses. A receiver amplifies, mixes, and digitizes the power developed in the cavity from possible axion-to-photon conversions. This is the most sensitive spectral receiver of microwave radiation in the world. The resulting data is scrutinized for an axion signal above the thermal background. ADMX first operated from 1995-2005 and produced exclusion limits on the energy of dark-matter axions from 1.9 mueV to 3.3 mueV. In order to improve on these limits and continue the search for plausible dark-matter axions, the system was considerably upgraded from 2005 until 2008. In the upgrade, the key technical advance was the use of a dc Superconducting QUantum Interference Device (SQUID) as a microwave amplifier. The SQUID amplifier's noise level is near
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.
Axion monodromy inflation with multi-natural modulations
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.
Axion and dilaton + metric emerge from local and linear electrodynamics
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...
Axion Dark Matter Coupling to Resonant Photons via Magnetic Field
McAllister, Ben T; Tobar, Michael E
2015-01-01
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 coupling is the same and implicitly 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 discuss the implications of the full electromagnetic form factor and propose new experiments using lumped 3D LC resonators (or re-entrant cavities) with separated electric and magnetic fields to probe currently unbounded regions of the axion mass parameter space.
Cosmology With Axionic-quintessence Coupled with Dark Matter
Kumar, Sumit; Sen, Anjan A
2013-01-01
We study the possibility of explaining the late time acceleration with an axion field which is coupled with the dark matter sector of the energy budget of the Universe. The axion field arises from the Ramond-Ramond sector of the Type-IIB string theory. We study the background evolution of the Universe as well as the growth of the matter perturbation in the linear regime. We subsequently use the observational data from Sn-Ia, BAO measurements, measurements of the Hubble parameter as well as the observational data for the growth of the matter perturbation to constrain our model. The results shows that higher coupling restricts the model to deviate more from the $\\Lambda$CDM behaviour.
Literature in Focus: "Axions: Theory, Cosmology, and Experimental Searches"
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...
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.
Axion cosmology, lattice QCD and the dilute instanton gas
International Nuclear Information System (INIS)
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.
Cosmologically Safe QCD Axion without Fine-Tuning.
Yamada, Masaki; Yanagida, Tsutomu T; Yonekura, Kazuya
2016-02-01
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 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. PMID:26894701
The topological susceptibility in finite temperature QCD and axion cosmology
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.
Subleading Effects and the Field Range in Axion Inflation
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.
Search for low Energy solar Axions with CAST
Arik, E; Autiero, D; Barth, K; Belov, A; Beltrán, B; Borghi, S; Boydag, F S; Bräuninger, H; Cantatore, G; Carmona, J M; Cebrián, S; Cetin, S A; Collar, J I; Dafni, T; Davenport, M; Di Lella, L; Dogan, O B; Eleftheriadis, C; Elias, N; Fanourakis, G K; Ferrer-Ribas, E; Fischer, H; Franz, J; Galán, J; Gazis, E; Geralis, T; Giomataris, Ioanis; Gninenko, S; Gómez, H; Hasinoff, M; Heinsius, F H; Hikmet, I; Hoffmann, D H H; Irastorza, I G; Jacoby, J; Jakovicic, K; Kang, D; Karageorgopoulou, T; Karuza, M; Königsmann, K C; Kotthaus, R; Krcmar, M; Kousouris, K; Kuster, M; Lakic, B; Lasseur, C; Liolios, A; Ljubicic, A; Lozza, V; Lutz, G; Luzón, G; Miller, D; Morales, A; Morales, J; Niinikoski, T; Nordt, A; Ortiz, A; Papaevangelou, T; Pivovaroff, M; Placci, A; Raiteri, G; Raffelt, G; Riege, H; Rodríguez, A; Ruz, J; Savvidis, I; Semertzidis, Y; Serpico, Pasquale Dario; Solanki, S K; Soufli, R; Stewart, L; Tsagri, M; Van Bibber, K; Villar, J; Vogel, J; Walckiers, L; Zioutas, K
2008-01-01
We have started the development of a detector system, sensitive to single photons in the eV energy range, to be suitably coupled to one of the CAST magnet ports. This system should open to CAST a window on possible detection of low energy Axion Like Particles emitted by the sun. Preliminary tests have involved a cooled photomultiplier tube coupled to the CAST magnet via a Galileian telescope and a switched 40 m long optical fiber. This system has reached the limit background level of the detector alone in ideal conditions, and two solar tracking runs have been performed with it at CAST. Such a measurement has never been done before with an axion helioscope. We will present results from these runs and briefly discuss future detector developments.
The CERN Axion Solar Telescope (CAST): Status and Prospects
International Nuclear Information System (INIS)
The CAST experiment is being mounted at CERN. It will make use of a decommissioned LHC test magnet to look for solar axions through its conversion into Photons inside the magnetic field. The magnet has a field of 9.6 Tesla and length of 10 m and is installed in a platform which allows to move it ±8 degrees vertically and ±40 degrees horizontally. According to these numbers we expect a sensitivity in axion-photon coupling gaγγ ∼-11 GeV-1 for ma ∼-2 eV, and with a gas filled tube gaγγ ∼-10 GeV-1 for ma ∼< 2 eV.
Subleading effects and the field range in axion inflation
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.
Axion Dark Matter Coupling to Resonant Photons via Magnetic Field.
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. PMID:27152793
Axion Dark Matter Coupling to Resonant Photons via Magnetic Field
McAllister, Ben T.; Parker, Stephen R.; Tobar, Michael E.
2016-04-01
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.
Cosmologically Safe QCD Axion without Fine-Tuning
Yamada, Masaki; Yanagida, Tsutomu T.; Yonekura, Kazuya
2016-02-01
Although QCD axion models are widely studied as solutions to the strong C P 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.
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.
An invisible axion model with controlled FCNCs at tree level
International Nuclear Information System (INIS)
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
Relativistic soliton collisions of axion type dark matter
Castañeda Valle, David; Mielke, Eckehard W.
2016-07-01
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 + 1)D or even (3 + 1)D and discuss a challenging intrinsic inelastic effect during relativistic soliton collisions.
The quest for axions and other new light particles
International Nuclear Information System (INIS)
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.
Relativistic soliton collisions of axion type dark matter
David Castañeda Valle; Mielke, Eckehard W.
2016-01-01
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+1)D or even (3+1)D and discuss a challenging intrinsic inelastic effect during relativistic soliton collisions.
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.
Axion condensate as a model for dark matter halos
International Nuclear Information System (INIS)
Localized solutions of an axion-like scalar model with a periodic self-interaction are analyzed as a model of dark matter halos. It is shown that such a cold Bose-Einstein type condensate can provide a substantial contribution to the observed rotations curves of galaxies, as well provide a soliton type interpretation of the dark matter 'bullets' observed via gravitational lensing in merging clusters
Axion condensate as a model for dark matter halos
Energy Technology Data Exchange (ETDEWEB)
Mielke, Eckehard W. [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, Apartado Postal 55-534, C.P. 09340, Mexico, DF (Mexico)], E-mail: ekke@xanum.uam.mx; Velez Perez, Jose A. [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, Apartado Postal 55-534, C.P. 09340, Mexico, DF (Mexico)], E-mail: josevel81@hotmail.com
2009-01-12
Localized solutions of an axion-like scalar model with a periodic self-interaction are analyzed as a model of dark matter halos. It is shown that such a cold Bose-Einstein type condensate can provide a substantial contribution to the observed rotations curves of galaxies, as well provide a soliton type interpretation of the dark matter 'bullets' observed via gravitational lensing in merging clusters.
Axion cold dark matter in non-standard cosmologies
Visinelli, Luca; Gondolo, Paolo
2009-01-01
We study the parameter space of cold dark matter axions in two cosmological scenarios with non-standard thermal histories before Big Bang nucleosynthesis: the Low Temperature Reheating (LTR) cosmology and the kination cosmology. If the Peccei-Quinn symmetry breaks during inflation, we find more allowed parameter space in the LTR cosmology than in the standard cosmology and less in the kination cosmology. On the contrary, if the Peccei-Quinn symmetry breaks after inflation, the Peccei-Quinn sc...
Signatures of Planck Corrections in a Spiralling Axion Inflation Model
McDonald, John
2014-01-01
The minimal sub-Planckian axion inflation model accounts for a large scalar-to-tensor ratio via a spiralling trajectory in the field space of a complex field $\\Phi$. Here we consider how the predictions of the model are modified by Planck scale-suppressed corrections. In the absence of Planck corrections the model is equivalent to a $\\phi^{4/3}$ chaotic inflation model. Planck corrections become important when the dimensionless coupling $\\xi$ of $|\\Phi|^{2}$ to the topological charge density ...
Axion electrodynamics and nonrelativistic photons in nuclear and quark matter
Yamamoto, Naoki
2016-04-01
We argue that the effective theory for electromagnetic fields in spatially varying meson condensations in dense nuclear and quark matter is given by the axion electrodynamics. We show that one of the helicity states of photons there has the nonrelativistic gapless dispersion relation ω ˜k2 at small momentum, while the other is gapped. This "nonrelativistic photon" may also be realized at the interface between topological and trivial insulators in condensed matter systems.
Revisiting the axion bounds from the Galactic white dwarf luminosity function
International Nuclear Information System (INIS)
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 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 Bol∼< 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 ma cos 2β∼> 5 meV (i.e. axion-electron coupling constant gae∼> 1.4× 10-13). We went beyond previous works by including 5 different derivations of the WDLF in our analysis. Then we have performed χ2-tests to have a quantitative measure of the agreement between the theoretical WDLFs — computed under the assumptions of different axion masses and normalization methods --- and the observed WDLFs of the Galactic disk. While all the WDLF studied in this work disfavour axion masses in the range suggested by asteroseismology ma cos 2β∼> 10 meV; gae∼> 2.8× 10-13) lower axion masses can not be discarded from our current knowledge of the WDLF of the Galactic Disk. A larger set of completely independent derivations of the WDLF of the galactic disk as well as a detailed study of the uncertainties of the theoretical WDLFs is needed before quantitative constraints on the axion-electron coupling constant can be made
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.
Cosmology of Axions and Moduli: A Dynamical Systems Approach
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...
Systematics of Axion Inflation in Calabi-Yau Hypersurfaces
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...
Baryogenesis from Strong CP Violation and the QCD Axion
Servant, Geraldine
2014-01-01
The strong CP-violating parameter is small today as indicated by constraints on the neutron electric dipole moment. In the early universe, the QCD axion has not yet relaxed to its QCD-cancelling minimum and it is natural to wonder whether this large CP violation could be responsible for baryogenesis. 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 EW baryogenesis if the EW 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 only new relevant ingredients beyond the Standard Model in our framework are the QCD axion and an EW scale dilaton-like scalar field. 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. Our conclusions are indepe...
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.
Axion Induced Oscillating Electric Dipole Moment of the Electron
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...
Gauge-preheating and the end of axion inflation
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.
Mediating Effect of Team Trust Between Team Conflict and Team Effectiveness in Self-management Teams
Wu Tiejun; Wang Wenjun; Bi Xin; Liu Dianzhi
2013-01-01
Team conflict is an amazing variable in team studies. But the effect of team conflict still remains debatable. Blessing or curse, it is not certain that team conflict is. It is reasonable that team type, team process and team context may influence the outcome of team conflict. In this study, 54 self-management teams were selected as participants, to explore the relationship between team conflict and team effectiveness. The result indicated that team conflic...
Teachers Initiating Conversations about Race and Racism in a High School Class
Bolgatz, Jane
2005-01-01
This qualitative study explores the techniques, materials and processes of a Black teacher and a White teacher who introduced issues of race and racism in their team-taught high school class. The teachers explicitly put the issues of race and racism on the table, asked questions that challenged students to think about the topics, and used…
Axionic domain wall number related to U(1)$_{\\rm anom}$ global symmetry
Kim, Jihn E
2016-01-01
The QCD axion with $f_a$ at an intermediate scale, 10**9-10**12 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.
Axionic domain wall number related to U(1)anom global symmetry
Kim, Jihn E.
2016-08-01
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.
Solar Axion search with Micromegas detectors in the CAST Experiment with $^{3}$He as buffer gas
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...
Status and Future of ADMX - the U.S. Microwave Cavity Axion Search Experiment
Energy Technology Data Exchange (ETDEWEB)
Kinion, D
2003-01-02
The author reports on the status of the Axion Dark-Matter Experiment (ADMX), the microwave-cavity-based axion search underway at Lawrence Livermore National Laboratory. The ADMX collaboration includes LLNL, the University of Florida, and M.I.T., and has been in operation since February, 1996.
Results and perspectives of the solar axion search with the CAST experiment
Ferrer-Ribas, E; 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; 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; Jakov\\vcić, 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; Vogel, J K; Yildiz, S C; Zioutas, K
2012-01-01
The status of the solar axion search with the CERN Axion Solar Telescope (CAST) will be presented. Recent results obtained by the use of $^3$He as a buffer gas has allowed us to extend our 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$ \\le m_{a} \\le $ 0.64 eV. From the absence of an excess of x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g$_{a\\gamma} \\le 2.3\\times 10^{-10}$ GeV$^{-1}$ at 95% C.L., the exact value depending on the pressure setting. CAST published results represent the best experimental limit on the photon couplings to axions and other similar exotic particles dubbed WISPs (Weakly Interacting Slim Particles) in the considered mass range and for the first time the limit enters the region favored by QCD axion models. Preliminary sensitivities for axion masses up to 1.16 eV will also be s...
Search for invisible axion, radiated in M1 transition of 125m Te
International Nuclear Information System (INIS)
Paper suggests a technique to search invisible axion radiated at M-transitions of isomeric nuclei. It is determined experimentally that at M1-transition of 125m Te nucleus the probability of axion radiation is ≤ 1.3 x 10-5 (90% reliability level)
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.
Determination of effective axion masses in the helium-3 buffer of CAST
International Nuclear Information System (INIS)
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/c2. 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/c2. 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.
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...
The search for axion-like dark matter using magnetic resonance
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.
Search for Solar Axions Produced in the $p + d \\rightarrow\\rm{^3He}+ A$ Reaction
Derbin, A V; Muratova, V N; 10.3103/S106287381006016X
2010-01-01
A search for the axioelectric absorption of 5.5-MeV solar axions produced in the $p+d\\rightarrow \\rm{^3He}+\\gamma(5.5 \\rm{MeV})$ reaction was performed with two BGO detectors placed inside a low-background setup. A model independent limit on axion-photon and axion-nucleon couplings was obtained: $|g_{Ae}\\times g_{AN}| \\leq 3.2\\times 10^{-9} (m_A=0)$. Constraints on the axion-electron coupling constant were obtained for axions with masses in the $(0.1-1.0)$ MeV range: $g_{Ae}\\leq (1.8-9.0)\\times 10^{-7}$. The solar positron flux from $A\\rightarrow e^-+e^+$ decay was determined for axions with masses $m_A > 2m_e$. Using the existing experimental data on the interplanetary positron flux, a new constraint on the axion-electron coupling constant for axions with masses in the $(1.2-5.4)$ MeV range was obtained: $g_{Ae} \\leq (1-5)\\times 10^{-17}$.
Can the Axions of Standard--like Superstring Models Solve the Strong CP Problem?
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.
Intelligence, race, and genetics.
Sternberg, Robert J; Grigorenko, Elena L; Kidd, Kenneth K
2005-01-01
In this article, the authors argue that the overwhelming portion of the literature on intelligence, race, and genetics is based on folk taxonomies rather than scientific analysis. They suggest that because theorists of intelligence disagree as to what it is, any consideration of its relationships to other constructs must be tentative at best. They further argue that race is a social construction with no scientific definition. Thus, studies of the relationship between race and other constructs may serve social ends but cannot serve scientific ends. No gene has yet been conclusively linked to intelligence, so attempts to provide a compelling genetic link of race to intelligence are not feasible at this time. The authors also show that heritability, a behavior-genetic concept, is inadequate in regard to providing such a link. PMID:15641921
Hasan, M. Mehedi
2013-01-01
In this workshop project, our intention is to arrange a Bike race event for the bike club’s members. Our project is based upon through a market research of Bike race event market. After analysing the market we have done a plan for our event, which structured by different tools of the project management, such as WBS, RBS etc. project management is the key tool in this project. Lastly we have shown our budget and financial structure of the event.
Probing axions with the neutrino signal from the next galactic supernova
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).
Search for solar axions with CsI(Tl) crystal detectors
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.
The 7 keV axion dark matter and the X-ray line signal
International Nuclear Information System (INIS)
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 ma≃7 keV and the decay constant fa≃1014–15 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.
Solving the tension between high-scale inflation and axion isocurvature perturbations
International Nuclear Information System (INIS)
The BICEP2 experiment determined the Hubble parameter during inflation to be about 1014 GeV. Such high inflation scale is in tension with the QCD axion dark matter if the Peccei–Quinn (PQ) symmetry remains broken during and after inflation, because too large axion isocurvature perturbations would be generated. The axion isocurvature perturbations can be suppressed if the axion acquires a sufficiently heavy mass during inflation. We show that this is realized if the PQ symmetry is explicitly broken down to a discrete symmetry and if the breaking is enhanced during inflation. We also show that, even when the PQ symmetry becomes spontaneously broken after inflation, such a temporarily enhanced PQ symmetry breaking relaxes the constraint on the axion decay constant
Excess astrophysical photons from a 0.1-1 keV cosmic axion background.
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 <10(-11) GeV(-1). We propose that 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. PMID:24160588
The QUAX proposal: a search of galactic axion with magnetic materials
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.
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.
Bezerra, V B; Mostepanenko, V M; Romero, C
2014-01-01
We calculate the additional force due to two-axion exchange acting in a sphere-disc geometry, used in experiments on measuring the gradient of the Casimir force. With this result, stronger constraints on the pseudoscalar coupling constants of an axion and axion-like particles to a proton and a neutron are obtained over the wide range of axion masses from 0.03mV to 1eV. Among the three experiments with Au-Au, Au-Ni and Ni-Ni boundary surfaces performed by means of dynamic atomic force microscope, major improving is achieved for the experiment with Au-Au test bodies. Here, the constraints obtained are stronger up to a factor of 170, as compared to the previously known ones. The largest strengthening holds for the axion mass 0.3eV.
Bezerra, V B; Mostepanenko, V M; Romero, C
2014-01-01
We obtain stronger laboratory constraints on the coupling constants of axion-like particles to nucleons from measurements of the normal and lateral Casimir forces between sinusoidally corrugated surfaces of a sphere and a plate. For this purpose, the normal and lateral additional force arising in the experimental configurations due to two-axion exchange between protons and neutrons are calculated. Our constraints following from measurements of the normal and lateral Casimir forces are stronger than the laboratory constraints reported so far for masses of axion-like particles larger than 11eV and 8eV, respectively. A comparison between various laboratory constraints on the coupling constants of axion-like particles to nucleons obtained from the magnetometer measurements, Eotvos- and Cavendish-type experiments, and from the Casimir effect is performed over the wide range of masses of axion-like particles from 10^{-10}eV to 20eV.
Bezerra, V. B.; Klimchitskaya, G. L.; Mostepanenko, V. M.; Romero, C.
2014-09-01
We obtain stronger laboratory constraints on the coupling constants of axion-like particles to nucleons from measurements of the normal and lateral Casimir forces between sinusoidally corrugated surfaces of a sphere and a plate. For this purpose, the normal and lateral additional forces arising in the experimental configurations due to the two-axion exchange between protons and neutrons are calculated. Our constraints following from measurements of the normal and lateral Casimir forces are stronger than the laboratory constraints reported so far for masses of axion-like particles larger than 11 and 8 eV, respectively. A comparison between various laboratory constraints on the coupling constants of axion-like particles to nucleons obtained from the magnetometer measurements, Eötvos- and Cavendish-type experiments, and from the Casimir effect is performed over the wide range of masses of axion-like particles from 10-10 to 20 eV.
Search for axioelectric effect of solar axions using BGO scintillating bolometer
Energy Technology Data Exchange (ETDEWEB)
Derbin, A.V.; Kayunov, A.S.; Muratova, V.N.; Semenov, D.A.; Unzhakov, E.V. [St. Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Gironi, L.; Biassoni, M.; Capelli, S.; Clemenza, M.; Ferri, E.; Giachero, A.; Gotti, C.; Maiano, C.; Maino, M.; Pavan, M.; Sisti, M. [INFN-Sezione di Milano Bicocca, Milano (Italy); Universita di Milano-Bicocca, Dipartimento di Fisica, Milano (Italy); Nagorny, S.S. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Gran Sasso Science Institute, INFN, L' Aquila, AQ (Italy); Pattavina, L.; Pirro, S. [INFN-Laboratori Nazionali del Gran Sasso, L' Aquila (Italy); Beeman, J.W. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Bellini, F. [INFN-Sezione di Roma, Rome (Italy); Universita di Roma La Sapienza, Dipartimento di Fisica, Rome (Italy); Drachnev, I.S. [St. Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Gran Sasso Science Institute, INFN, L' Aquila, AQ (Italy)
2014-09-15
A search for axioelectric absorption of solar axions produced in the p + d → {sup 3}He + γ(5.5 MeV) reaction has been performed with a BGO detector placed in a low-background setup. A model-independent limit on the combination of axion.nucleon and axion.electron coupling constants has been obtained: vertical stroke g{sub Ae} x g{sup 3}{sub AN} vertical stroke < 1.9 x 10{sup -10} for 90 % confidence level. The constraint of the axion.electron coupling constant has been obtained for hadronic axion with masses of (0.1.1) MeV: vertical stroke g{sub Ae} vertical stroke ≤ (0.96. 8.2) x 10{sup -8}. (orig.)
Goparaju Purna SUDHAKAR
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...
Team Learning and Team Composition in Nursing
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…
Arik, M; Barth, K.; Belov, A.; Borghi, S.; Brauninger, 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.; Galan, J.; Garcia, J.A.; Gardikiotis, A.; Garza, J.G.; Gazis, E.N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gomez, H.; Gomez Marzoa, M.; Gruber, E.; Guthorl, T.; Hartmann, R.; Hauf, S.; 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.; Lang, P.M.; Laurent, J.M.; Liolios, A.; Ljubicic, A.; Lozza, V.; Luzon, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Papaevangelou, T.; Pivovaroff, M.J.; Raffelt, G.; Riege, H.; Rodriguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Silva, P.S.; Solanki, S.K.; Stewart, L.; Tomas, 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.
Hanson, H
1993-01-01
Early 20th century race biology takes a special interest in woman as part of the "intra-racial" project of bringing forth healthy and competitive individuals. But there are other motives as well for the race biologist to take an interest in woman. She is believed to develop fewer individual characteristics and is therefore a more typical representative of her race than man. The development level of the race is also presupposed to be discernible by the degree of "gender diformism": a race of higher standing would exhibit a greater difference between the sexes. The anthropologist, anatomist, gynaecologist--or whatever guise the race biologist may adopt-- will, in principle, stress that the relation between the sexes is not a matter of "more or less", but one of differences in kind. In reality, the "more-or-less of comparison is the very cornerstone of the issue. Quantitative differences, directly observed or obtained from statistics, are construed as signs of difference in kind. 18th century medical philosophy and sex-linked anthropology laid the theoretical foundation of the 19th century essentialist conception of woman, which is also that adopted by race biology. Eugenics of social Darwinist inspiration regarded prophylactic health care and social welfare programs with scepticism. A race biology founded on the man-woman dualism could sustain altogether different conclusions. An advanced culture calls for extensive division of labour. An extended childhood renders possible higher development but will also impose higher demands on woman. The protection of the female organism is thus an exigency for any people or race striving to survive and evolve. From society's care for the female organism health care for women and preventive maternity care will emerge. Race biology has been a preeminently German concern, as indicated by the selection of works taken to represent this perspective on woman: Bartels-Ploss' Das Weib, C.H. Stratz' Die Rassenschönheit des Weibes and
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...
Stadnik, Y V
2013-01-01
We show that the interaction of an axion field, or in general a pseudoscalar field, with the axial-vector current generated by an electron through a derivative-type coupling can give rise to a time-dependent mixing of opposite-parity states in atomic and molecular systems. Likewise, the analogous interaction of an axion field with the axial-vector current generated by a nucleon can give rise to time-dependent mixing of opposite-parity states in nuclear systems. This mixing can induce oscillating electric dipole moments, oscillating parity non-conservation effects and oscillating anapole moments in such systems. By adjusting the energy separation between the opposite-parity states of interest to match the axion mass energy, axion-induced experimental observables can be enhanced by many orders of magnitude. Oscillating atomic electric dipole moments can also be generated by axions through hadronic mechanisms, namely the P,T-violating nucleon-nucleon interaction and through the axion-induced electric dipole mome...
Supersymmetric SU(11), the invisible axion, and proton decay
International Nuclear Information System (INIS)
We supersymmetrize the very attractive flavour unification model SU(11). As with other supersymmetric GUTs the gauge hierarchy problem is simplified, but we may also have observable (tausub(p) is approximately 1033 yrs) proton decay. The required split multiplets are obtained by making the adjoint take a particular direction. Supersymmetry is broken softly at the TeV scale. There is a unique U(1)sub(A) symmetry, and hence there are no true Nambu-Goldstone bosons. The U(1)sub(A) is broken at the GUT scale and there result an invisible axion and neutrino masses. (author)
Strong dynamics or axion origin of the diphoton excess
Molinaro, Emiliano; Vignaroli, Natascia
2015-01-01
ATLAS and CMS observe deviations from the expected background in the diphoton invariant mass searches of new resonances around 750 GeV. We show that a simple realization in terms of a new pseudoscalar state can accommodate the observations. The model leads to further footprints that can be soon observed. The new state can be interpreted both as an axion or as a composite state stemming from minimal models of dynamical electroweak symmetry breaking. We further provide insights on how to disentangle the two scenarios.
On Axionic Field Ranges, Loopholes and the Weak Gravity Conjecture
Brown, Jon; Shiu, Gary; Soler, Pablo
2015-01-01
In this short note we clarify some aspects of the impact that the Weak Gravity Conjecture has on models of (generalized) natural inflation. We address in particular certain technical and conceptual concerns recently raised regarding the stringent constraints and conclusions found in our previous work (arXiv:1503.04783). We also point out the difficulties faced by attempts to evade these constraints. These new considerations improve the understanding of the quantum gravity constraints we found and further support the conclusion that it remains challenging for axions to drive natural inflation.
Photon-axion conversion in Active Galactic Nuclei?
Bassan, Nicola
2009-01-01
Axion-Like Particles (ALPs) are the focus of intense current research. We analyze photon-ALP conversion in the context of relativistic jet models of Active Galactic Nuclei (AGN) for more than 100 sources. Contrary to previous claims, we find that this process cannot occur above 100 GeV regardless of the actual AGN model and the values of ALP parameters. This result rules out a proposed strategy to bypass the cosmic opacity above 100 GeV, as apparently required by observations. We also show that for some AGN an observable effect can show up in the X and soft gamma-ray bands.
Roulette Inflation with K\\"ahler Moduli and their Axions
Bond, J. R.; Kofman, L.; Prokushkin, S.; 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...
Sanders, David
2010-01-01
This paper describes some early results from observing and interviewing groups working to achieve intellectually complex tasks that required the use of computers, WWW and other research resources. Three groups were virtual (they were working at a distance and rarely meeting face to face) and two groups were simple control groups They were real groups (working in relatively close proximity so that face to face contact was possible most of the time). All five teams completed their tasks but a s...
Sichrovský, Jan
2013-01-01
Virtual environment is part of the newly forming area, which is becoming more and more attractive for businesses to use its own potential. Even though it is a very dynamic issue, the goals of this work is providing a detailed description of the aspects of team work in these unusual conditions. The result is a material that not only summarizes the current knowledge, but try to move forward, including many practical views and experiences. The first part focuses on the general definition of ...
Search for Solar Axions with the CCD Detector and X-ray Telescope at CAST Experiment
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...
CAST search for sub-eV mass solar axions with $^{3}$He buffer gas
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.
Detailed design of a resonantly enhanced axion-photon regeneration experiment
International Nuclear Information System (INIS)
A resonantly enhanced photon-regeneration experiment to search for the axion or axionlike particles is described. This experiment is a shining light through walls study, where photons traveling through a strong magnetic field are (in part) converted to axions; the axions can pass through an opaque wall and convert (in part) back to photons in a second region of strong magnetic field. The photon regeneration is enhanced by employing matched Fabry-Perot optical cavities, with one cavity within the axion generation magnet and the second within the photon-regeneration magnet. Compared to simple single-pass photon regeneration, this technique would result in a gain of (F/π)2, where F is the finesse of each cavity. This gain could feasibly be as high as 1010, corresponding to an improvement in the sensitivity to the axion-photon coupling, gaγγ, of order (F/π)1/2∼300. This improvement would enable, for the first time, a purely laboratory experiment to probe axion-photon couplings at a level competitive with, or superior to, limits from stellar evolution or solar axion searches. This report gives a detailed discussion of the scheme for actively controlling the two Fabry-Perot cavities and the laser frequencies, and describes the heterodyne signal detection system, with limits ultimately imposed by shot noise.
Probing the eV-Mass Range for Solar Axions with the CAST Experiment
VOGEL, Julia
2009-01-01
The CERN Axion Solar Telescope (CAST) is searching for solar axions, which could be produced in the core of the Sun via the so-called Primakoff effect. For this purpose, CAST uses a decommissioned LHC prototype magnet. In its magnetic field of 9 Tesla, axions could be reconverted into X-ray photons. The magnet is mounted on a structure built to follow the Sun during sunrise and sunset for a total of about 3 hours per day. The analysis of the data acquired during the first phase of the experiment with vacuum in the magnetic field region yielded the most restrictive experimental upper limit on the axion-to-photon coupling constant for axion masses up to about 0.02 eV. In order to extend the sensitivity of the experiment to a wider mass range, the CAST experiment continued its search for axions with helium in the magnet bores. In this way it is possible to restore coherence for larger masses. Changing the pressure of the helium gas enables the experiment to scan different axion masses. In the first part of this ...
DEFF Research Database (Denmark)
Gondan, Matthias; Heckel, A.
2008-01-01
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......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...... are presented with onset asynchrony. We demonstrate how the kill-the-twin procedure is used in a statistical test of the race model prediction....
Team responsibility structure and team performance
Doorewaard, J.A.C.M.; Hootegem, G. van; Huys, R.
2002-01-01
The purpose is to analyse the impact of team responsibility (the division of job regulation tasks between team leader and team members) on team performance. It bases an analysis on 36 case studies in The Netherlands which are known to have implemented team-based work. The case studies were executed
The quest for an intermediate-scale accidental axion and further ALPs
International Nuclear Information System (INIS)
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 1013 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 109 GeV and 1013 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.
Probing the eV-mass range for solar axions with the CAST experiment
International Nuclear Information System (INIS)
The CERN Axion Solar Telescope (CAST) is searching for solar axions, which could be produced in the core of the Sun via the so-called Primakoff effect. For this purpose, CAST uses a decommissioned LHC prototype magnet. In its magnetic field of 9 Tesla axions could be reconverted into X-ray photons. The magnet is mounted on a structure built to follow the Sun during sunrise and sunset for a total of about 3 hours per day. The analysis of the data acquired during the first phase of the experiment with vacuum in the magnetic field region yielded the most restrictive experimental upper limit on the axion-to-photon coupling constant for axion masses up to about 0.02 eV. In order to extend the sensitivity of the experiment to a wider mass range, the CAST experiment continued its search for axions with helium in the magnet bores. In this way it is possible to restore coherence for larger masses. Changing the pressure of the helium gas enables the experiment to scan different axion masses. In the first part of this second phase of CAST, helium-4 has been used and the axion mass region was extended up to 0.4 eV. Therefore the experiment enters the regions favored by axion models. In CAST's ongoing helium-3 phase the studied mass range is now further extended. We will present the final results of CAST's helium-4 phase. Furthermore the latest upgrades of the experiments will be shown and an outlook on CAST's status and prospects will be given. (author)
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.
International Nuclear Information System (INIS)
Written in 1961, this paper presents the content of a book entitled 'The arms race control' where the author outlined the difference between disarmament and arms control, described the economic and moral role of arms race, the importance of force balance for international security. He wandered whether arms control could ensure this balance and whether nuclear balance meant force balance. Force balance then appears to be a precarious and unsteady component of international security. He commented the challenges of disarmament, recalled some arguments for a nuclear disarmament. Then he discussed what would be an arms control with or without disarmament (either nuclear or conventional)
Photoproduction of axions on electrons in a constant external field: the Primakoff effect
International Nuclear Information System (INIS)
We calculate the cross section of the reaction γ+e→e+a in the constant crossed electromagnetic field via the Primakoff process which is due to the direct axion-photon interaction. We point out the effect of the resonant axion production in the kinematic region where the virtual photon emitted by an electron goes off to the mass shell. We obtain the resonance contribution to the total cross section of the process and on this basis we estimate an upper bound on the axion mass: ma-2 eV. 19 refs
Photon Production From The Scattering of Axions Out of a Solenoidal Magnetic Field
Guendelman, Eduardo I; Cantatore, Giovanni; Zioutas, Konstantin
2009-01-01
In this paper we calculate the total cross section for the production of photons from the scattering of axions by a strong inhomogeneous magnetic field in the form of a cylindrical step function and a 2D delta function, which can be approximately produced by a solenoidal current. The theoretical result is used to estimate the total number of events and the axion-photon conversion probability which could be expected in a reasonable experimental situation. The calculated conversion probabilities for QCD inspired axions are much larger than those derived by applying the celebrated 1D calculation of the (inverse) coherent Primakoff effect.
Experimental Search for Solar Axions via Coherent Primakoff Conversion in a Germanium Spectrometer
Avignone, F. T.; Abriola, D.; Brodzinski, R. L.; J. I. Collar; Creswick, R.J.; DiGregorio, D. E.; Farach, H. A.; Gattone, A. O.; Guerard, C. K.; Hasenbalg, F.; Huck, H.; Miley, H. S.; Morales, A.; MORALES, J., CRUZ, D., DELGADO, P., LIZANA, M., LÓPEZ, V.; Nussinov, S.
1997-01-01
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...
Searches for axioelectric effect of solar axions with BGO-scintillator and BGO-bolometer detectors
Muratova, V N; Giorni, L; Nagorny, S S; Pattavina, L; Bakhlanov, S V; Beeman, J W; Bellini, F; Biassoni, M; Capelli, S; Clemenza, M; Dratchnev, I S; Ferri, E; Giachero, A; Gotti, C; Kayunov, A S; Maiano, C; Maino, M; Pavan, M; Pirro, S; Semenov, D A; Sisti, M; Unzhakov, E V
2015-01-01
A search for axioelectric absorption of 5.5 MeV solar axions produced in the $p + d \\rightarrow {^3\\rm{He}}+\\gamma~(5.5~ \\rm{MeV})$ reaction has been performed with a BGO detectors. A model-independent limit on the product of axion-nucleon $g_{AN}^3$ and axion-electron $g_{Ae}$ coupling constants has been obtained: $| g_{Ae}\\times g_{AN}^3|< 1.9\\times 10^{-10}$ for 90\\% C.L..
The Einstein-Maxwell-aether-axion theory: Dynamo-optical anomaly in the electromagnetic response
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.
New model of axion monodromy inflation and its cosmological implications
Cai, Yi-Fu; Chen, Fang; Ferreira, Elisa G. M.; Quintin, Jerome
2016-06-01
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.
Axion monodromy inflation with warped KK-modes
International Nuclear Information System (INIS)
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.
Axion monodromy inflation with warped KK-modes
Directory of Open Access Journals (Sweden)
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.
Stueckelberg Axions and Anomalous Abelian Extensions of the Standard Model
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...
Axion Monodromy Inflation with Warped KK-Modes
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.
Axion monodromy inflation with warped KK-modes
Hebecker, Arthur; Moritz, Jakob; Westphal, Alexander; Witkowski, Lukas T.
2016-03-01
We present a particularly simple model of axion monodromy inflation: Our axion is the lowest-lying KK-mode of the RR-2-form-potential 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.
Roulette inflation with Kaehler moduli and their axions
International Nuclear Information System (INIS)
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 Kaehler modulus τ corresponding to a 4-cycle volume and its axionic partner θ. The freedom associated with the choice of Calabi-Yau manifold and the nonperturbative effects defining the potential V(τ,θ) and kinetic parameters of the moduli brings an unavoidable statistical element to theory prior probabilities within the low-energy landscape. The further randomness of (τ,θ) initial conditions allows for a large ensemble of trajectories. Features in the ensemble of histories include 'roulette trajectories', with long-lasting inflations in the direction of the rolling axion, enhanced in the number of e-foldings over those restricted to lie in the τ-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 microwave background and large scale structure data. In particular, the observed scalar tilt with weak or no running can be achieved in spite of a nearly critical de Sitter deceleration parameter and consequently a low gravity wave power relative to the scalar curvature power
Roulette inflation with Kähler moduli and their axions
Bond, J. Richard; Kofman, Lev; Prokushkin, Sergey; Vaudrevange, Pascal M.
2007-06-01
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 Kähler modulus τ corresponding to a 4-cycle volume and its axionic partner θ. The freedom associated with the choice of Calabi-Yau manifold and the nonperturbative effects defining the potential V(τ,θ) and kinetic parameters of the moduli brings an unavoidable statistical element to theory prior probabilities within the low-energy landscape. The further randomness of (τ,θ) initial conditions allows for a large ensemble of trajectories. Features in the ensemble of histories include “roulette trajectories,” with long-lasting inflations in the direction of the rolling axion, enhanced in the number of e-foldings over those restricted to lie in the τ-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 microwave background and large scale structure data. In particular, the observed scalar tilt with weak or no running can be achieved in spite of a nearly critical de Sitter deceleration parameter and consequently a low gravity wave power relative to the scalar curvature power.
Roulette Inflation with K\\"ahler Moduli and their Axions
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...
A. M'charek
2011-01-01
What is biological race and how is it made relevant in specific practices? How to address the materiality of biological race without fixing it? And how to write about it without reifying race as a singular object? These are the central questions in this short essay. Instead of debunking or trivializ
2009-01-01
The CERN relay race, now in its 39th year, is already a well-known tradition, but this year the organizers say the event will have even more of a festival feeling. Just off the starting line of the CERN relay race.For the past few years, spectators and runners at the CERN relay race have been able to enjoy a beer while listening to music from the CERN music and jazz clubs. But this year the organizers are aiming for "even more of a festival atmosphere". As David Nisbet, President of the CERN running club and organizer of the relay race, says: "Work is not just about getting your head down and doing the theory, it’s also about enjoying the company of your colleagues." This year, on top of music from the Santa Luis Band and the Canettes Blues Band, there will be demonstrations from the Aikido and softball clubs, a stretching session by the Fitness club, as well as various stalls and of course, the well-earned beer from AGLUP, the B...
DEFF Research Database (Denmark)
Landes, Xavier; Andersen, Martin Marchman; Nielsen, Morten Ebbe Juul
2012-01-01
increased pressure to produce articles (in peer-reviewed journals) has created an unbalanced emphasis on the research criterion at the expense of the latter two. More fatally, this pressure has turned academia into a rat race, leading to a deep change in the fundamental structure of academic behaviour, and...
Jeynes, William H.
2011-01-01
This article examines the views of Darwinist evolution on issues regarding race and how this contributed to the spread of racism in the United States. The writings of Charles Darwin and a myriad of his followers are examined, including Herbert Spencer, Francis Galton, and others. The influence of Darwinism in contributing to the growth of…
International Nuclear Information System (INIS)
The management of new arms races in the region of Asia-Pacific includes considerations of weapons trade and transfer in the region, with an emphasis on nuclear weapons proliferation. It deals with the problem of controlling the arms trade and the efforts to control conventional weapons and underlines the possible role and influence of Conference on Cooperation and Security in Europe (CSCE)
Klaus Hanke
2013-01-01
The 2013 edition of the annual CERN Road Race will be held on Wednesday 18 September at 18.15. The 5.5 km race takes place over 3 laps of a 1.8 km circuit in the West Area of the Meyrin site, and is open to everyone working at CERN and their families. There are runners of all speeds, with times ranging from under 17 to over 34 minutes, and the race is run on a handicap basis, by staggering the starting times so that (in theory) all runners finish together. Children (< 15 years) have their own race over 1 lap of 1.8 km. As usual, there will be a “best family” challenge (judged on best parent + best child). Trophies are awarded in the usual men’s, women’s and veterans’ categories, and there is a challenge for the best age/performance. Every adult will receive a souvenir prize, financed by a registration fee of 10 CHF. Children enter free (each child will receive a medal). More information, and the online entry form, can be found at: htt...
Klaus Hanke
2013-01-01
The 2013 annual CERN Road Race will be held on Wednesday 18 September at 6.15 p.m. The 5.5 km race takes place over 3 laps of a 1.8 km circuit in the West Area of the Meyrin site, and is open to everyone working at CERN and their families. There are runners of all speeds, with times ranging from under 17 to over 34 minutes, and the race is run on a handicap basis, by staggering the starting times so that (in theory) all runners finish together. Children (< 15 years) have their own race over 1 lap of 1.8 km. As usual, there will be a “best family” challenge (judged on best parent and best child). Trophies are awarded in the usual men’s, women’s and veterans’ categories, and there is a challenge for the best age/performance. Every adult will receive a souvenir prize, financed by a registration fee of 10 CHF. Children enter free (each child will receive a medal). More information, and the online entry form, can be found here.
Ballard, Roger
2002-01-01
Prepared for a textbook in sociology, this paper offers a clear set of definitions for the three crucial but much contended concepts of race, ethnicity and culture, and having done so explores how they can be used to make sense of the dynamics of pluralism in contemporary Britain.
Race, Emotions, and Socialization.
Smith, James E.
2002-01-01
Investigated the connection between emotion and behavior, examining the connection between the construct of emotional intelligence and criminal behavior. Data collected from a group of men and women on probation from prison indicated that people received different socialization with regard to emotions based on gender and race. Results suggest that…
Electromagnetic waves in an axion-active relativistic plasma non-minimally coupled to gravity
International Nuclear Information System (INIS)
We consider cosmological applications of a new self-consistent system of equations, accounting for a non-minimal coupling of the gravitational, electromagnetic and pseudoscalar (axion) fields in a relativistic plasma. We focus on dispersion relations for electromagnetic perturbations in an initially isotropic ultrarelativistic plasma coupled to the gravitational and axion fields in the framework of isotropic homogeneous cosmological model of the de Sitter type. We classify the longitudinal and transversal electromagnetic modes in an axionically active plasma and distinguish between waves (damping, instable or running), and nonharmonic perturbations (damping or instable). We show that for the special choice of the guiding model parameters the transversal electromagnetic waves in the axionically active plasma, non-minimally coupled to gravity, can propagate with the phase velocity smaller than the speed of light in vacuum, thus displaying a possibility for a new type of resonant particle-wave interactions. (orig.)
Academic Training: Joint ILIAS-CAST-CERN Axion Training at CERN
Françoise Benz
2005-01-01
2005-2006 ACADEMIC TRAINING PROGRAMME 30 November, 1 and 2 December PLACE - DETAILS: http://agenda.cern.ch/fullAgenda.php?ida=a056218 Joint ILIAS-CAST-CERN Axion Training at CERN The ILIAS (Integrated Large Infrastructure for Astroparticle Science) is co-organising a 3 day academic training session together with the CAST collaboration and the CERN Academic Training Programme on physics related to axion research, including open discussions between theorists and experimentalists. The intention of the lectures is to provide academic training for scientists engaged in axion research and to facilitate the often missing link between experiment and theory with the aim of encouraging young researchers to communicate with experts in the field. The lectures include topics which are not regularly covered by standard lectures at universities and should lead to a deeper understanding of the physics related to axions, which covers a broad field from QCD to astrophysics and cosmology. There will be an opportunity for ...
Academic Training: Joint ILIAS-CAST-CERN Axion Training at CERN
Françoise Benz
2005-01-01
2005-2006 ACADEMIC TRAINING PROGRAMME 30 November, 1 and 2 December PLACE - DETAILS: http://agenda.cern.ch/fullAgenda.php?ida=a056218 Joint ILIAS-CAST-CERN Axion Training at CERN The ILIAS (Integrated Large Infrastructure for Astroparticle Science) is co-organising a 3 day academic training session together with the CAST collaboration and the CERN Academic Training Programme on physics related to axion research, including open discussions between theorists and experimentalists. The intention of the lectures is to provide academic training for scientists engaged in axion research and to facilitate the often missing link between experiment and theory with the aim of encouraging young researchers to communicate with experts in the field. The lectures include topics which are not regularly covered by standard lectures at universities and should lead to a deeper understanding of the physics related to axions, which covers a broad field from QCD to astrophysics and cosmology. There will be an opportunity for ...
Bose-Einstein condensation of the classical axion field in cosmology?
International Nuclear Information System (INIS)
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, and argues that ''gravitational thermalisation'' drives them to a Bose-Einstein condensate during the radiation dominated era. Using classical equations of motion during linear structure formation, we explore whether the gravitational interactions of axions can generate enough entropy. At linear order in GN, we interpret that the principle activities of gravity are to expand the Universe and grow density fluctuations. To quantify the rate of entropy creation we use the anisotropic stress to estimate a short dissipation scale for axions which does not confirm previous estimates of their gravitational thermalisation rate
Bose-Einstein condensation of the classical axion field in cosmology?
Energy Technology Data Exchange (ETDEWEB)
Davidson, Sacha; Elmer, Martin, E-mail: s.davidson@ipnl.in2p3.fr, E-mail: m.elmer@ipnl.in2p3.fr [IPNL, Université de Lyon, Université Lyon 1, CNRS/IN2P3, 4 rue E. Fermi, Villeurbanne cedex, 69622 (France)
2013-12-01
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, and argues that ''gravitational thermalisation'' drives them to a Bose-Einstein condensate during the radiation dominated era. Using classical equations of motion during linear structure formation, we explore whether the gravitational interactions of axions can generate enough entropy. At linear order in G{sub N}, we interpret that the principle activities of gravity are to expand the Universe and grow density fluctuations. To quantify the rate of entropy creation we use the anisotropic stress to estimate a short dissipation scale for axions which does not confirm previous estimates of their gravitational thermalisation rate.
Proceedings of the 4th Patras workshop on axions, WIMPs and WISPs
International Nuclear Information System (INIS)
The following topics were dealt with: Physical foundations for WIMPs, axions, and WISPS, signals from astrophysical sources, direct searches for dark matter WIMPs, new theoretical developments, new experimental approaches. (HSI)
6th Patras workshop on axions, WIMPs and WISPs (PATRAS 2010). Proceedings
International Nuclear Information System (INIS)
The following topics were dealt with: Axions, WIMPs, WISPs, and neutrinos in the universe, laboratory experimental searching for WISPs, astrophysical experimental searching for WISPs, direct and indirect detection of WIMPs, new ideas and developments, visions, large laboratories. (HSI)
Proceedings of the 4th Patras workshop on axions, WIMPs and WISPs
Energy Technology Data Exchange (ETDEWEB)
Lindner, Axel; Redondo, Javier; Ringwald, Andreas (eds.)
2008-08-15
The following topics were dealt with: Physical foundations for WIMPs, axions, and WISPS, signals from astrophysical sources, direct searches for dark matter WIMPs, new theoretical developments, new experimental approaches. (HSI)
Constraints on the parameters of axion from measurements of thermal Casimir-Polder force
Bezerra, V B; Mostepanenko, V M; Romero, C
2014-01-01
Stronger constraints on the pseudoscalar coupling constants of an axion and axion-like particles with a proton and a neutron are obtained from measurements of the thermal Casimir-Polder force between a Bose-Einstein condensate of $^{87}$Rb atoms and a SiO$_2$ plate. For this purpose the additional force acting between a condensate cloud and a plate due to two-axion exchange is calculated. The obtained constraints refer to the axion masses from 0.1meV to 0.3eV which overlap with the region from 0.01meV to 10meV considered at the moment as the most prospective.