Cosmological and experimental constraints on the tau neutrino

Sarkar, S.; Cooper, A.M.

doi:10.1016/0370-2693(84)90101-1

Cited by 113 publications

(54 citation statements)

References 45 publications

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“…One of the standard distortions, known as the Compton y-distortion, is created in the regime of inefficient energy transfer between electrons and photons, relevant at redshift z 5 × 10 4 . Processes creating this type of distortion include the inverse-Compton scattering of CMB photons off hot electrons during the epoch of reionization and structure formation Hu et al 1994b;Refregier & et al 2000;Hill et al 2015), also known in connection with the thermal Sunyaev-Zeldovich (tSZ) effect (Zeldovich & Sunyaev 1969), but can also be related to non-standard physics, e.g., the presence of long-lived decaying particles (Sarkar & Cooper 1984;Ellis et al 1992;Hu & Silk 1993b;Chluba 2013a).…”

Section: Introductionmentioning

confidence: 99%

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Abitbol

Chluba

Hill

et al. 2017

Monthly Notices of the Royal Astronomical Society

146

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Measurements of cosmic microwave background spectral distortions have profound implications for our understanding of physical processes taking place over a vast window in cosmological history. Foreground contamination is unavoidable in such measurements and detailed signal-foreground separation will be necessary to extract cosmological science. In this paper, we present MCMC-based spectral distortion detection forecasts in the presence of Galactic and extragalactic foregrounds for a range of possible experimental configurations, focusing on the Primordial Inflation Explorer (PIXIE) as a fiducial concept. We consider modifications to the baseline PIXIE mission (operating 12 months in distortion mode), searching for optimal configurations using a Fisher approach. Using only spectral information, we forecast an extended PIXIE mission to detect the expected average non-relativistic and relativistic thermal Sunyaev-Zeldovich distortions at high significance (194σ and 11σ, respectively), even in the presence of foregrounds. The ΛCDM Silk damping µ-type distortion is not detected without additional modifications of the instrument or external data. Galactic synchrotron radiation is the most problematic source of contamination in this respect, an issue that could be mitigated by combining PIXIE data with future ground-based observations at low frequencies (ν 15 − 30 GHz). Assuming moderate external information on the synchrotron spectrum, we project an upper limit of |µ| < 3.6 × 10 −7 (95% c.l.), slightly more than one order of magnitude above the fiducial ΛCDM signal from the damping of small-scale primordial fluctuations, but a factor of 250 improvement over the current upper limit from COBE/FIRAS. This limit could be further reduced to |µ| < 9.4 × 10 −8 (95% c.l.) with more optimistic assumptions about extra low-frequency information and would rule out many alternative inflation models as well as provide new constraints on decaying particle scenarios.

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Section: Introductionmentioning

confidence: 99%

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Abitbol

Chluba

Hill

et al. 2017

Monthly Notices of the Royal Astronomical Society

146

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“…We can now identify the temperature T m at which the particle energy density ρ x (≃ m x n x ) would † This assumes thermalization of the released energy which is very efficient for decay lifetimes < ∼ 10 5 sec (Illarianov andSunyaev 1975, Sarkar andCooper 1984). For longer lifetimes thermalization is incomplete, but then the absence of a spectral distortion in the CMBR sets equally restrictive constraints on the decaying particle abundance (e.g.…”

Section: Bounds On Non-relativistic Relicsmentioning

confidence: 99%

“…We emphasize that this bound is more general than the similar one (5.7) which only applies to Dirac neutrinos which decay 'invisibly' after nucleosynthesis. Sarkar and Cooper (1984) had argued that a ν τ lighter than 1 MeV has no decay modes which are fast enough to satisfy the constraint (5.8) from the energy density. The radiative decay ν τ → ν e γ is generally too slow and in any case is observationally required to have a lifetime greater than the age of the universe (see Sciama 1993).…”

Section: Neutrino Decaysmentioning

confidence: 99%

Big bang nucleosynthesis and physics beyond the standard model

1996

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Abstract. The Hubble expansion of galaxies, the 2.73 K blackbody radiation background and the cosmic abundances of the light elements argue for a hot, dense origin of the universe -the standard Big Bang cosmology -and enable its evolution to be traced back fairly reliably to the nucleosynthesis era when the temperature was of O(1) MeV corresponding to an expansion age of O(1) sec. All particles, known and hypothetical, would have been created at higher temperatures in the early universe and analyses of their possible effects on the abundances of the synthesized elements enable many interesting constraints to be obtained on particle properties. These arguments have usefully complemented laboratory experiments in guiding attempts to extend physics beyond the Standard SU (3) c ⊗SU (2) L ⊗U (1) Y Model, incorporating ideas such as supersymmetry, compositeness and unification. We first present a pedagogical account of relativistic cosmology and primordial nucleosynthesis, discussing both theoretical and observational aspects, and then proceed to examine such constraints in detail, in particular those pertaining to new massless particles and massive unstable particles. Finally, in a section aimed at particle physicists, we illustrate applications of such constraints to models of new physics.

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“…Commonly discussed spectral distortions are primarily due to energy release (Zeldovich & Sunyaev 1969;Sunyaev & Zeldovich 1970;Burigana et al 1991;Hu & Silk 1993a), for example, because of decaying relic particles (Sarkar & Cooper 1984;Kawasaki & Sato 1986;Hu & Silk 1993b; or the damping of primordial acoustic waves at small scales (Hu et al 1994a;Chluba et al 2012b,a), which causes µ-, y-and r-distortions. In the future, these signals may be detected with an experiment similar to PIXIE (Kogut et al 2011), a satellite concept which could provide a major leap forward in sensitivity over COBE/FIRAS (Fixsen et al 1996) and may open a new unexplored window to the early Universe.…”

Section: Introductionmentioning

confidence: 99%

Green's function of the cosmological thermalization problem – II. Effect of photon injection and constraints

Chluba

2015

Mon. Not. R. Astron. Soc.

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The energy spectrum of the cosmic microwave background (CMB) provides a powerful tool for constraining standard and non-standard physics in the primordial Universe. Previous studies mainly highlight spectral distortions (µ-, y-and r-type) created by episodes of early energy release; however, several processes also lead to copious photon production, which requires a different treatment. Here, we carry out a first detailed study for the evolution of distortions caused by photon injection at different energies in the CMB bands. We provide detailed analytical and numerical calculations illustrating the rich phenomenology of the associated distortion signals. We show that photon injection at very high and very low frequencies creates distortions that are similar to those from pure energy release. In the µ-era (z 3 × 10 5 ), a positive or negative chemical potential can be formed, depending on the balance between added photon energy and number. At lower redshifts (z 3 × 10 5 ), partial information about the photon injection process (i.e., injection time and energy) can still be recovered, with the distortion being found in a partially Comptonized state. We briefly discuss current and future constraints on scenarios with photon production. We also argue that more detailed calculations for different scenarios with photon injection may be required to assess in which regimes these can be distinguished from pure energy release processes.

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Cosmological and experimental constraints on the tau neutrino

Cited by 113 publications

References 45 publications

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Prospects for measuring cosmic microwave background spectral distortions in the presence of foregrounds

Big bang nucleosynthesis and physics beyond the standard model

Green's function of the cosmological thermalization problem – II. Effect of photon injection and constraints

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