Explore the Lifetime Frontier with MATHUSLA

EPJ Web of Conferences ◽

10.1051/epjconf/201818202004 ◽

2018 ◽

Vol 182 ◽

pp. 02004

Author(s):

Cristiano Alpigiani

Keyword(s):

Big Bang ◽

Small Scale ◽

Interaction Point ◽

Big Bang Nucleosynthesis ◽

Hadronic Jets ◽

Proton Proton ◽

Weakly Coupled ◽

Surface Detector ◽

General Production ◽

Main Detector

Many extensions of the Standard Model (SM) include particles that are neutral, weakly coupled, and long-lived that can decay to final states containing several hadronic jets. Long-lived particles (LLPs) can be detected as displaced decays from the interaction point, or missing energy if they escape. ATLAS and CMS have performed searches at the LHC and significant exclusion limits have been set in recent years. However, the current searches performed at colliders have limitations. An LLP does not interact with the detector and it is only visible once it decays. Unfortunately, no existing or proposed search strategy will be able to observe the decay of non-hadronic electrically neutral LLPs with masses above GeV and lifetimes near the limit set by Big Bang Nucleosynthesis (cπ ~ 107 - 108 m). Therefore, ultra-long-lived particles (ULLPs) produced at the LHC will escape the main detector with extremely high probability. MATHUSLA (MAssive Timing Hodoscope for Ultra Stable neutraL pArticles) is a surface detector, which can be implemented with existing technology and in time for the high luminosity LHC upgrade to find such ultra-long-lived particles, whether produced in exotic Higgs decays or more general production modes. The MATHUSLA detector will consist of resistive plate chambers (RPC) and scintillators with a total sensitive area of 200 x 200 m2. It will be installed on the surface, close to the ATLAS or CMS detectors. A small-scale test detector (~ 6m2) is going to be installed on the surface above ATLAS in November 2017. It will consist of three layers of RPCs used for timing/tracking and two layers of scintillators for timing measurements. It will be placed above the ATLAS interaction point to estimate cosmic backgrounds and proton-proton backgrounds coming from ATLAS during nominal LHC operations.

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Nonlinear matter terms in general scalar–tensor braneworld cosmology

International Journal of Modern Physics D ◽

10.1142/s0218271819501384 ◽

2019 ◽

Vol 28 (11) ◽

pp. 1950138

Author(s):

Kevin F. S. Pardede ◽

Agus Suroso ◽

Freddy P. Zen

Keyword(s):

Big Bang ◽

Accelerated Expansion ◽

Big Bang Nucleosynthesis ◽

Braneworld Cosmology ◽

Strongly Coupled ◽

Weakly Coupled ◽

General Scalar ◽

Bulk Scalar Field ◽

The Big Bang ◽

Correction Terms

A five-dimensional braneworld cosmological model in general scalar–tensor action that is comprised of various Horndeski Lagrangians is considered. The Friedmann equations in the case of strongly and weakly coupled [Formula: see text] Horndeski Lagrangians have been obtained. The strongly coupled [Formula: see text] model produces the Cardassian term [Formula: see text] with [Formula: see text], which can serve as an alternative explanation for the accelerated expansion phase of the universe. Furthermore, the latest combined observational facts from BAO, CMB, SNIa, [Formula: see text] and [Formula: see text] value observation suggest that the [Formula: see text] term lies quite close to the constrained value. On the other hand, the weakly coupled [Formula: see text] case has several new correction terms which are omitted in the braneworld Einstein–Hilbert model, e.g. the cubic [Formula: see text] and the dark radiation–matter interaction term [Formula: see text]. Furthermore, this model provides a cosmological constant constructed from the bulk scalar field, requires no brane tension and supports the big bang nucleosynthesis (BBN) constraint naturally.

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Revisiting constraints on small scale perturbations from big-bang nucleosynthesis

Physical Review D ◽

10.1103/physrevd.94.043527 ◽

2016 ◽

Vol 94 (4) ◽

Cited By ~ 17

Author(s):

Keisuke Inomata ◽

Masahiro Kawasaki ◽

Yuichiro Tada

Keyword(s):

Big Bang ◽

Small Scale ◽

Big Bang Nucleosynthesis

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Velocity-dependent self-interacting dark matter from thermal freeze-out and tests in direct detections

The European Physical Journal C ◽

10.1140/epjc/s10052-020-7656-9 ◽

2020 ◽

Vol 80 (2) ◽

Author(s):

Lian-Bao Jia

Keyword(s):

Dark Matter ◽

Wave Process ◽

Massive Particle ◽

Big Bang ◽

Small Scale ◽

Big Bang Nucleosynthesis ◽

Light Scalar ◽

Nucleus Scattering ◽

Main Component ◽

Wimp Search

Abstract A small fraction of millicharged dark matter (DM) is considered in the literature to give an interpretation of the enhanced 21-cm absorption at the cosmic dawn. Here we focus on the case that the main component of DM is self-interacting dark matter (SIDM), motivated by the small-scale problems. For self-interactions of SIDM being compatible from dwarf to cluster scales, velocity-dependent self-interactions mediated by a light scalar $$\phi $$ϕ are considered. For fermionic SIDM $$\Psi $$Ψ, the main annihilation mode $$\Psi \bar{\Psi } \rightarrow \phi \phi $$ΨΨ¯→ϕϕ is a p-wave process. The thermal transition of SIDM $$\rightleftarrows \phi \rightleftarrows $$⇄ϕ⇄ standard model (SM) particles in the early universe sets a lower bound on couplings of $$\phi $$ϕ to SM particles, which has been excluded by direct detections of DM, and here we consider SIDM in thermal equilibrium via millicharged DM. For $$m_\phi>$$mϕ> twice millicharged DM mass, $$\phi $$ϕ could decay quickly and avoid excess energy injection to big bang nucleosynthesis. Thus, the $$\phi $$ϕ–SM particle couplings could be very tiny and evade direct detections of DM. The picture of weakly interacting massive particle (WIMP)–nucleus scattering with contact interactions fails for SIDM–nucleus scattering with a light mediator, and a method is explored in this paper with which a WIMP search result can be converted into the hunt for SIDM in direct detections.

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Cannibalism's lingering imprint on the matter power spectrum

Journal of Cosmology and Astroparticle Physics ◽

10.1088/1475-7516/2022/01/017 ◽

2022 ◽

Vol 2022 (01) ◽

pp. 017

Author(s):

Adrienne L. Erickcek ◽

Pranjal Ralegankar ◽

Jessie Shelton

Keyword(s):

Dark Matter ◽

Power Spectrum ◽

Big Bang ◽

Small Scale ◽

Thermal Bath ◽

Dark Sector ◽

Big Bang Nucleosynthesis ◽

Particle Properties ◽

Matter Power Spectrum ◽

Expansion Of The Universe

Abstract The early universe may have contained internally thermalized dark sectors that were decoupled from the Standard Model. In such scenarios, the relic dark thermal bath, composed of the lightest particle in the dark sector, can give rise to an epoch of early matter domination prior to Big Bang Nucleosynthesis, which has a potentially observable impact on the smallest dark matter structures. This lightest dark particle can easily and generically have number-changing self-interactions that give rise to “cannibal” behavior. We consider cosmologies where an initially sub-dominant cannibal species comes to temporarily drive the expansion of the universe, and we provide a simple map between the particle properties of the cannibal species and the key features of the enhanced dark matter perturbation growth in such cosmologies. We further demonstrate that cannibal self-interactions can determine the small-scale cutoff in the matter power spectrum even when the cannibal self-interactions freeze out prior to cannibal domination.

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Smallest remnants of early matter domination

Journal of Cosmology and Astroparticle Physics ◽

10.1088/1475-7516/2021/12/026 ◽

2021 ◽

Vol 2021 (12) ◽

pp. 026

Author(s):

Gabriela Barenboim ◽

Nikita Blinov ◽

Albert Stebbins

Keyword(s):

Dark Matter ◽

Power Spectra ◽

Big Bang ◽

Rapid Expansion ◽

Small Scale ◽

Late Time ◽

Big Bang Nucleosynthesis ◽

Density Profiles ◽

Short Period ◽

Linear Effects

Abstract The evolution of the universe prior to Big Bang Nucleosynthesis could have gone through a phase of early matter domination which enhanced the growth of small-scale dark matter structure. If this period was long enough, self-gravitating objects formed prior to reheating. We study the evolution of these dense early halos through reheating. At the end of early matter domination, the early halos undergo rapid expansion and eventually eject their matter. We find that this process washes out structure on scales much larger than naively expected from the size of the original halos. We compute the density profiles of the early halo remnants and use them to construct late-time power spectra that include these non-linear effects. We evolve the resulting power spectrum to estimate the properties of microhalos that would form after matter-radiation equality. Surprisingly, cosmologies with a short period of early matter domination lead to an earlier onset of microhalo formation compared to those with a long period. In either case, dark matter structure formation begins much earlier than in the standard cosmology, with most dark matter bound in microhalos in the late universe.

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What's Next for Big Bang Nucleosynthesis?

Nuclear Physics A ◽

10.1016/j.nuclphysa.2005.05.139 ◽

2005 ◽

Vol 758 ◽

pp. 771-774

Author(s):

R.H. Cyburt

Keyword(s):

Big Bang ◽

Big Bang Nucleosynthesis

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Refined big bang nucleosynthesis constraints onΩBandNν

Physical Review Letters ◽

10.1103/physrevlett.72.3309 ◽

1994 ◽

Vol 72 (21) ◽

pp. 3309-3312 ◽

Cited By ~ 80

Author(s):

Peter J. Kernan ◽

Lawrence M. Krauss

Keyword(s):

Big Bang ◽

Big Bang Nucleosynthesis

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Searching for space-time variation of the fine structure constant using QSO spectra: overview and future prospects

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310009440 ◽

2009 ◽

Vol 5 (H15) ◽

pp. 304-304

Author(s):

J. C. Berengut ◽

V. A. Dzuba ◽

V. V. Flambaum ◽

J. A. King ◽

M. G. Kozlov ◽

...

Keyword(s):

Nuclear Reactor ◽

Structure Constant ◽

Big Bang ◽

The Other ◽

Fine Structure Constant ◽

Spatial And Temporal Variation ◽

Fundamental Constants ◽

Future Prospects ◽

Big Bang Nucleosynthesis ◽

The Universe

Current theories that seek to unify gravity with the other fundamental interactions suggest that spatial and temporal variation of fundamental constants is a possibility, or even a necessity, in an expanding Universe. Several studies have tried to probe the values of constants at earlier stages in the evolution of the Universe, using tools such as big-bang nucleosynthesis, the Oklo natural nuclear reactor, quasar absorption spectra, and atomic clocks (see, e.g. Flambaum & Berengut (2009)).

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