A search for anomalously heavy isotopes of low Z nuclei

Hemmick, T.K.; Elmore, D.; Kubik, Peter W.; Olsen, S. L.; Gentile, Thomas R.; Nitz, D.; Ciampa, D.; Kagan, H.; Haas, P.; Smith, P. F.; McInteer, B.B.; Bigeleisen, Jacob

doi:10.1016/0168-583x(87)90271-0

Cited by 38 publications

(36 citation statements)

References 22 publications

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“…A detailed investigation of this possibility is beyond the scope of this work, but such a strongly interacting dark matter (SIMP) candidate appears to be heavily disfavored as discussed for example in refs. [54][55][56][57][58][59][60].…”

Section: Jhep09(2014)130mentioning

confidence: 99%

Survey of vector-like fermion extensions of the Standard Model and their phenomenological implications

Ellis

Godbole

Gopalakrishna

et al. 2014

J. High Energ. Phys.

111

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With the renewed interest in vector-like fermion extensions of the Standard Model, we present here a study of multiple vector-like theories and their phenomenological implications. Our focus is mostly on minimal flavor conserving theories that couple the vector-like fermions to the SM gauge fields and mix only weakly with SM fermions so as to avoid flavor problems. We present calculations for precision electroweak and vector-like state decays, which are needed to investigate compatibility with currently known data. We investigate the impact of vector-like fermions on Higgs boson production and decay, including loop contributions, in a wide variety of vector-like extensions and their parameter spaces.

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Section: Jhep09(2014)130mentioning

confidence: 99%

Survey of vector-like fermion extensions of the Standard Model and their phenomenological implications

Ellis

Godbole

Gopalakrishna

et al. 2014

J. High Energ. Phys.

111

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“…Our goal is however to have the RHN as the only DM. Furthermore, heavy colored particles with masses up to a few TeV are incompatible with bounds on anomalous nuclei [80][81][82]. Masses heavier than this also seem to be excluded by considerations of DM-cosmic ray interactions producing gamma rays [83] and DM capture and self-annihilation in Earth's core producing internal heat flow [84,85].…”

Section: Depleting the Heavy Hadronic Statesmentioning

confidence: 99%

Naturally stable right-handed neutrino dark matter

Dev

Mohapatra

Zhang

2016

J. High Energ. Phys.

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Abstract:We point out that a class of non-supersymmetric models based on the gauge group SU(3) C × SU(2) L × SU(2) R × U(1) Y L × U(1) Y R possesses an automatic, exact Z 2 symmetry under which the fermions in the SU(2) R × U(1) Y R sector (called R-sector) are odd and those in the SU(2) L ×U(1) Y L sector (called L-sector or the Standard Model sector) are even. This symmetry, which is different from the usual parity symmetry of the leftright symmetric models, persists in the lepton sector even after the gauge symmetry breaks down to SU(3) C × U(1) EM . This keeps the lightest right-handed neutrino naturally stable, thereby allowing it to play the role of dark matter (DM) in the Universe. There are several differences between the usual left-right models and the model presented here: (i) our model can have two versions, one which has no parity symmetry so that the couplings and masses in the L and R sectors are unrelated, and another which has parity symmetry so that couplings are related but with an extra Higgs doublet in each sector so that the fermion mass patterns are different; (ii) the R-sector fermions are chosen much heavier than the Lsector ones in both scenarios; and finally (iii) both light and heavy neutrinos are Majorana fermions with the light neutrino masses arising from a pure type-II seesaw mechanism. We discuss the DM relic density, direct and indirect detection prospects and associated collider signatures of the model. Comparing with current collider and direct detection constraints, we find a lower bound on the DM mass of order of 1 TeV. We also point out a way to relax the DM unitarity bound in our model for much larger DM masses by an entropy dilution mechanism. An additional feature of the model is that the DM can be made very long lived, if desired, by allowing for weak breaking of the above Z 2 symmetry. Our model also predicts the existence of long-lived colored particles which could be searched for at the LHC.

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“…Hemmick et al [7] used the AMS spectrometer at the University of Rochester to search for anomalously heavy isotopes and set abundance limits of 10 -15 -10 -10 (before including the enrichment factors) in the mass range of 10 2 -10 4 amu. In this work, the samples of Li, Be, B, and F were obtained from common commercial chemicals.…”

Section: Figurementioning

confidence: 99%

“…We caution that there is only a weak relationship between the limits set by these searches, which are based on very different sets of assumptions. The methods used are: mass spectrometry [6]; accelerator mass spectrometry [7,8,15,17]; density [6]; laser spectroscopy [14,18]; Rutherford back scattering [9]; γ-ray emission [13]. RBS [9] GRE [13] 2 H density [6] Na Laser [18] Au AMS [8] Fe [8] Be AMS [7] 2 H AMS [7] Li [7] B [7] F [7] 18 O [7] 14 C [7] He [14] 244 Pu RBS [9] 18 O [17] Be [15] Li [15] 2.2 Accelerator mass spectrometry (AMS), 2 H, Be, Li, B, F, 18 O, 14 C The low background achieved in the previous low-energy (10-100 keV) mass analysis is only feasible with +1e charged particle due to the complete absence of mass isobars.…”

Section: Figurementioning

confidence: 99%

Searches for stable strangelets in ordinary matter: overview and a recent example

Müller

O’Connor

et al. 2005

Nuclear Physics A

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Our knowledge on the possible existence in nature of stable exotic particles depends solely upon experimental observation. Guided by this general principle and motivated by theoretical hypotheses on the existence of stable particles of strange quark matter, a variety of experimental searches have been performed. We provide an introduction to the theoretical hypotheses, an overview of the past searches, and a more detailed description of a recent search for helium-like strangelets in the Earth's atmosphere using a sensitive laser spectroscopy method. Is it possible that ordinary nuclear matter that we are familiar with is actually metastable and slowly decaying into quark matter of lower energy? Many hypotheses have been proposed addressing this question. Bodmer first proposed a lower-energy nuclear state, which he called "collapsed nuclei" [1]. Witten investigated the stability of strange quark matter, which consists of approximately equal number of u, d and s quarks in a hadronic state, and reached the intriguing conclusion that it may indeed be stable even at zero external pressure [2]. A particle of strange quark matter is called a "strangelet". Searches for such exotic matter have been performed in astronomical observation, in cosmic rays, in heavy-ion collisions, and in chemical analyses of ordinary matter. Several excellent review articles on this subject are available [3][4][5]. Here we focus on one aspect of the subject: the experimental searches for stable strangelets in ordinary matter. In Section 1, we provide a brief pedagogical introduction to strange quark matter and strangelets; in Section 2, we review the past searches; in Section 3, we present our recent search for helium-like strangelets in the Earth's atmosphere.

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A search for anomalously heavy isotopes of low Z nuclei

Cited by 38 publications

References 22 publications

Survey of vector-like fermion extensions of the Standard Model and their phenomenological implications

Survey of vector-like fermion extensions of the Standard Model and their phenomenological implications

Naturally stable right-handed neutrino dark matter

Searches for stable strangelets in ordinary matter: overview and a recent example

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