Silicon detector dark matter results from the final exposure of CDMS II

Search for Dark-Matter-Nucleon Interactions via Migdal Effect with DarkSide-50

Dark matter elastic scattering off nuclei can result in the excitation and ionization of the recoiling atom through the so-called Migdal effect. The energy deposition from the ionization electron adds to the energy deposited by the recoiling nuclear system and allows for the detection of interactions of sub-GeV/c^{2} mass dark matter. We present new constraints for sub-GeV/c^{2} dark matter using the dual-phase liquid argon time projection chamber of the DarkSide-50 experiment with an exposure of (12 306±184)  kg d. The analysis is based on the ionization signal alone and significantly enhances the sensitivity of DarkSide-50, enabling sensitivity to dark matter with masses down to 40  MeV/c^{2}. Furthermore, it sets the most stringent upper limit on the spin independent dark matter nucleon cross section for masses below 3.6  GeV/c^{2}.

Dark Matter Effects on the Compact Star Properties

The neutron star properties are generally determined by the equation of state of β-equilibrated dense matter. In this work, we consider the interaction of fermionic dark matter (DM) particles with nucleons via Higgs exchange and investigate the effect on the neutron star properties with the relativistic mean-field model equation of state coupled with DM. We deduce that DM significantly affects the neutron star properties, such as considerably reducing the maximum mass of the star, which depends on the percentage of the DM considered inside the neutron star. The tidal Love numbers both for electric and magnetic cases and surficial Love numbers are also studied for DM admixed NS. We observed that the magnitude of tidal and surficial Love numbers increases with a greater DM percentage. Further, we present post-Newtonian tidal corrections to gravitational waves decreased by increasing the DM percentage. The DM effect on the GW signal is significant during the late inspiral and merger stages of binary evolution for GW frequencies >500 Hz.

Cold Particle Dark Matter

Possible dark matter candidates in particle physics span a mass range extending over fifty orders of magnitude. In this review, we consider the range of masses from a few keV to a few hundred TeV, which is relevant for cold particle dark matter. We will consider models where dark matter arises as weakly coupled elementary fields and models where dark matter is a composite state bound by a new strong interaction. Different production mechanisms for dark matter in these models will be described. The landscape of direct and indirect searches for dark matter and some of the resulting constraints on models will be briefly discussed.

Reduced Thermal Conductivity in Ultrafast Laser Heated Silicon Measured by Time-Resolved X-ray Diffraction

We investigate the effect of free carrier dynamics on heat transport in bulk crystalline Silicon following femtosecond optical excitation of varying fluences. By taking advantage of the dense 500 MHz standard fill pattern in the PLS-II storage ring, we perform high angular-resolution X-ray diffraction measurements on nanosecond-to-microsecond time-scales with femtometer spatial sensitivity. We find noticeably slowed lattice recovery at increasingly high excitation intensities. Modeling the temporal evolution of lattice displacements due to the migration of the near surface generated heat into the bulk requires reduced thermal diffusion coefficients. We attribute this pump-fluence dependent thermal transport behavior to two separate effects: first, the enhanced nonradiative recombination of free carriers, and, second, reduced size of the effective heat source in the material. These results demonstrate the capability of time-resolved X-ray scattering as an effective means to explore the connection between charge carrier dynamics and macroscopic transport properties.

Results on Low-Mass Weakly Interacting Massive Particles from an 11 kg d Target Exposure of DAMIC at SNOLAB

We present constraints on the existence of weakly interacting massive particles (WIMPs) from an 11 kg d target exposure of the DAMIC experiment at the SNOLAB underground laboratory. The observed energy spectrum and spatial distribution of ionization events with electron-equivalent energies >200  eV_{ee} in the DAMIC CCDs are consistent with backgrounds from natural radioactivity. An excess of ionization events is observed above the analysis threshold of 50  eV_{ee}. While the origin of this low-energy excess requires further investigation, our data exclude spin-independent WIMP-nucleon scattering cross sections σ_{χ-n} as low as 3×10^{-41}  cm^{2} for WIMPs with masses m_{χ} from 7 to 10  GeV c^{-2}. These results are the strongest constraints from a silicon target on the existence of WIMPs with m_{χ}<9  GeV c^{-2} and are directly relevant to any dark matter interpretation of the excess of nuclear-recoil events observed by the CDMS silicon experiment in 2013.

Search for a Light CP-odd Higgs Boson and Low-Mass Dark Matter at the Belle Experiment

We report on the first Belle search for a light CP-odd Higgs boson, A^{0}, that decays into low mass dark matter, χ, in final states with a single photon and missing energy. We search for events produced via the dipion transition ϒ(2S)→ϒ(1S)π^{+}π^{-}, followed by the on-shell process ϒ(1S)→γA^{0} with A^{0}→χχ, or by the off-shell process ϒ(1S)→γχχ. Utilizing a data sample of 157.3×10^{6} ϒ(2S) decays, we find no evidence for a signal. We set limits on the branching fractions of such processes in the mass ranges M_{A^{0}}<8.97  GeV/c^{2} and M_{χ}<4.44  GeV/c^{2}. We then use the limits on the off-shell process to set competitive limits on WIMP-nucleon scattering in the WIMP mass range below 5  GeV/c^{2}.

Quad-Band Plasmonic Perfect Absorber for Visible Light with a Patchwork of Silicon Nanorod Resonators

In this paper, a plasmonic perfect absorber (PPA) based on a silicon nanorod resonator (SNRR) for visible light is proposed and investigated numerically. The proposed PPA is only a two-layer nanostructure consisting of a SNRR periodic array and metal substrate. The perfect absorption mainly originates from excitation of the localized surface plasmon resonance (LSPR) mode in the SNRR structure. The absorption properties of this design can be adjusted by varying the radius (r) and height (h) of the SNRR structure. What is more, the stronger quad-band absorption can be achieved by combing four different radius of the SNRR in one period as a super unit-cell. Numerical simulation indicates that the designed quad-band PPA can achieve the absorbance of 99.99%, 99.8%, 99.8%, and 92.2% at 433.5 THz, 456 THz, 482 THz, and 504.5 THz, respectively. Further simulations show that the proposed PPA is polarization-insensitive for both transverse electric (TE) and transverse magnetic (TM) modes. The proposed PPA can be a desirable candidate for some potential applications in detecting, sensing, and visible spectroscopy.

Low-Mass Dark Matter Search with the DarkSide-50 Experiment

We present the results of a search for dark matter weakly interacting massive particles (WIMPs) in the mass range below 20  GeV/c^{2} using a target of low-radioactivity argon with a 6786.0 kg d exposure. The data were obtained using the DarkSide-50 apparatus at Laboratori Nazionali del Gran Sasso. The analysis is based on the ionization signal, for which the DarkSide-50 time projection chamber is fully efficient at 0.1  keVee. The observed rate in the detector at 0.5  keVee is about 1.5  event/keVee/kg/d and is almost entirely accounted for by known background sources. We obtain a 90% C.L. exclusion limit above 1.8  GeV/c^{2} for the spin-independent cross section of dark matter WIMPs on nucleons, extending the exclusion region for dark matter below previous limits in the range 1.8-6  GeV/c^{2}.

Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg×day Data of the CDEX-10 Experiment

We report the first results of a light weakly interacting massive particles (WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector array immersed in liquid nitrogen at the China Jinping Underground Laboratory with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee, improved limits of 8×10^{-42} and 3×10^{-36}  cm^{2} at a 90% confidence level on spin-independent and spin-dependent WIMP-nucleon cross sections, respectively, at a WIMP mass (m_{χ}) of 5  GeV/c^{2} are achieved. The lower reach of m_{χ} is extended to 2  GeV/c^{2}.

WIMP dark matter candidates and searches-current status and future prospects

We review several current aspects of dark matter theory and experiment. We overview the present experimental status, which includes current bounds and recent claims and hints of a possible signal in a wide range of experiments: direct detection in underground laboratories, gamma-ray, cosmic ray, x-ray, neutrino telescopes, and the LHC. We briefly review several possible particle candidates for a weakly interactive massive particle (WIMP) and dark matter that have recently been considered in the literature. We pay particular attention to the lightest neutralino of supersymmetry as it remains the best motivated candidate for dark matter and also shows excellent detection prospects. Finally we briefly review some alternative scenarios that can considerably alter properties and prospects for the detection of dark matter obtained within the standard thermal WIMP paradigm.

The waning of the WIMP? A review of models, searches, and constraints

Weakly Interacting Massive Particles (WIMPs) are among the best-motivated dark matter candidates. No conclusive signal, despite an extensive search program that combines, often in a complementary way, direct, indirect, and collider probes, has been detected so far. This situation might change in near future due to the advent of one/multi-TON Direct Detection experiments. We thus, find it timely to provide a review of the WIMP paradigm with focus on a few models which can be probed at best by these facilities. Collider and Indirect Detection, nevertheless, will not be neglected when they represent a complementary probe.

Results from the Super Cryogenic Dark Matter Search Experiment at Soudan

We report the result of a blinded search for weakly interacting massive particles (WIMPs) using the majority of the SuperCDMS Soudan data set. With an exposure of 1690 kg d, a single candidate event is observed, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP-nucleon cross section of 1.4×10^{-44} (1.0×10^{-44})  cm^{2} at 46  GeV/c^{2}. These results set the strongest limits for WIMP-germanium-nucleus interactions for masses >12  GeV/c^{2}.

Detection of magnetized quark-nuggets, a candidate for dark matter

Quark nuggets are theoretical objects composed of approximately equal numbers of up, down, and strange quarks and are also called strangelets and nuclearites. They have been proposed as a candidate for dark matter, which constitutes ~85% of the universe’s mass and which has been a mystery for decades. Previous efforts to detect quark nuggets assumed that the nuclear-density core interacts directly with the surrounding matter so the stopping power is minimal. Tatsumi found that quark nuggets could well exist as a ferromagnetic liquid with a ~10¹²-T magnetic field. We find that the magnetic field produces a magnetopause with surrounding plasma, as the earth’s magnetic field produces a magnetopause with the solar wind, and substantially increases their energy deposition rate in matter. We use the magnetopause model to compute the energy deposition as a function of quark-nugget mass and to analyze testing the quark-nugget hypothesis for dark matter by observations in air, water, and land. We conclude the water option is most promising.

Light weakly interacting massive particles

Light weakly interacting massive particles (WIMPs) are dark matter particle candidates with weak scale interaction with the known particles, and mass in the GeV to tens of GeV range. Hints of light WIMPs have appeared in several dark matter searches in the last decade. The unprecedented possible coincidence into tantalizingly close regions of mass and cross section of four separate direct detection experimental hints and a potential indirect detection signal in gamma rays from the galactic center, aroused considerable interest in our field. Even if these hints did not so far result in a discovery, they have had a significant impact in our field. Here we review the evidence for and against light WIMPs as dark matter candidates and discuss future relevant experiments and observations.

TREX-DM: a low-background Micromegas-based TPC for low-mass WIMP detection

If Dark Matter is made of Weakly Interacting Massive Particles (WIMPs) with masses below [Formula: see text] GeV, the corresponding nuclear recoils in mainstream WIMP experiments are of energies too close, or below, the experimental threshold. Gas Time Projection Chambers (TPCs) can be operated with a variety of target elements, offer good tracking capabilities and, on account of the amplification in gas, very low thresholds are achievable. Recent advances in electronics and in novel radiopure TPC readouts, especially micro-mesh gas structure (Micromegas), are improving the scalability and low-background prospects of gaseous TPCs. Here we present TREX-DM, a prototype to test the concept of a Micromegas-based TPC to search for low-mass WIMPs. The detector is designed to host an active mass of [Formula: see text] kg of Ar at 10 bar, or alternatively [Formula: see text] kg of Ne at 10 bar, with an energy threshold below 0.4 keVee, and is fully built with radiopure materials. We will describe the detector in detail, the results from the commissioning phase on surface, as well as a preliminary background model. The anticipated sensitivity of this technique may go beyond current experimental limits for WIMPs of masses of 2-8 GeV.

New Results from the Search for Low-Mass Weakly Interacting Massive Particles with the CDMS Low Ionization Threshold Experiment

The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg day, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5  GeV/c^{2}.

Physics at the [Formula: see text] linear collider

A comprehensive review of physics at an [Formula: see text] linear collider in the energy range of [Formula: see text] GeV-3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well as astroparticle physics. The report focusses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.

Low-temperature thermodynamics with quantum coherence

Thermal operations are an operational model of non-equilibrium quantum thermodynamics. In the absence of coherence between energy levels, exact state transition conditions under thermal operations are known in terms of a mathematical relation called thermo-majorization. But incorporating coherence has turned out to be challenging, even under the relatively tractable model wherein all Gibbs state-preserving quantum channels are included. Here we find a mathematical generalization of thermal operations at low temperatures, ‘cooling maps', for which we derive the necessary and sufficient state transition condition. Cooling maps that saturate recently discovered bounds on coherence transfer are realizable as thermal operations, motivating us to conjecture that all cooling maps are thermal operations. Cooling maps, though a less-conservative generalization to thermal operations, are more tractable than Gibbs-preserving operations, suggesting that cooling map-like models at general temperatures could be of use in gaining insight about thermal operations.

Thermal operations, a model of thermodynamic processes for small quantum systems out of equilibrium, are well-understood in absence of coherence. Here the authors introduce cooling processes, a generalization of thermal operations and find necessary and sufficient conditions for coherent state transitions via cooling processes.

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at [Formula: see text]TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb[Formula: see text] of [Formula: see text] TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with [Formula: see text] GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between [Formula: see text] GeV and [Formula: see text] GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presented.

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at [Formula: see text]TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb[Formula: see text] of [Formula: see text] TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with [Formula: see text] GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between [Formula: see text] GeV and [Formula: see text] GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presented.

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Search for dark matter, extra dimensions, and unparticles in monojet events in proton-proton collisions at [Formula: see text][Formula: see text]

Results are presented from a search for particle dark matter (DM), extra dimensions, and unparticles using events containing a jet and an imbalance in transverse momentum. The data were collected by the CMS detector in proton-proton collisions at the LHC and correspond to an integrated luminosity of 19.7[Formula: see text]at a centre-of-mass energy of 8[Formula: see text]. The number of observed events is found to be consistent with the standard model prediction. Limits are placed on the DM-nucleon scattering cross section as a function of the DM particle mass for spin-dependent and spin-independent interactions. Limits are also placed on the scale parameter [Formula: see text] in the Arkani-Hamed, Dimopoulos, and Dvali (ADD) model of large extra dimensions, and on the unparticle model parameter [Formula: see text]. The constraints on ADD models and unparticles are the most stringent limits in this channel and those on the DM-nucleon scattering cross section are an improvement over previous collider results.

Search for neutrinos from annihilation of captured low-mass dark matter particles in the sun by super-kamiokande

Super-Kamiokande (SK) can search for weakly interacting massive particles (WIMPs) by detecting neutrinos produced from WIMP annihilations occurring inside the Sun. In this analysis, we include neutrino events with interaction vertices in the detector in addition to upward-going muons produced in the surrounding rock. Compared to the previous result, which used the upward-going muons only, the signal acceptances for light (few-GeV/c^{2}-200-GeV/c^{2}) WIMPs are significantly increased. We fit 3903 days of SK data to search for the contribution of neutrinos from WIMP annihilation in the Sun. We found no significant excess over expected atmospheric-neutrino background and the result is interpreted in terms of upper limits on WIMP-nucleon elastic scattering cross sections under different assumptions about the annihilation channel. We set the current best limits on the spin-dependent WIMP-proton cross section for WIMP masses below 200  GeV/c^{2} (at 10  GeV/c^{2}, 1.49×10^{-39}  cm^{2} for χχ→bb[over ¯] and 1.31×10^{-40}  cm^{2} for χχ→τ^{+}τ^{-} annihilation channels), also ruling out some fraction of WIMP candidates with spin-independent coupling in the few-GeV/c^{2} mass range.

Dark matter with pseudoscalar-mediated interactions explains the DAMA signal and the galactic center excess

We study a Dirac dark matter particle interacting with ordinary matter via the exchange of a light pseudoscalar, and analyze its impact on both direct and indirect detection experiments. We show that this candidate can accommodate the long-standing DAMA modulated signal and yet be compatible with all exclusion limits at 99(S)% C.L. This result holds for natural choices of the pseudoscalar-quark couplings (e.g., flavor universal), which give rise to a significant enhancement of the dark matter-proton coupling with respect to the coupling to neutrons. We also find that this candidate can accommodate the observed 1-3 GeV gamma-ray excess at the Galactic center and at the same time have the correct relic density today. The model could be tested with measurements of rare meson decays, flavor changing processes, and searches for axionlike particles with mass in the MeV range.

Limiting P-odd interactions of cosmic fields with electrons, protons, and neutrons

We propose methods for extracting limits on the strength of P-odd interactions of pseudoscalar and pseudovector cosmic fields with electrons, protons, and neutrons, by exploiting the static and dynamic parity-nonconserving amplitudes and electric dipole moments they induce in atoms. Candidates for such fields are dark matter (including axions) and dark energy, as well as several more exotic sources described by Lorentz-violating standard model extensions. Atomic calculations are performed for H, Li, Na, K, Rb, Cs, Ba(+), Tl, Dy, Fr, and Ra(+). From these calculations and existing measurements in Dy, Cs, and Tl, we constrain the interaction strengths of the parity-violating static pseudovector cosmic field to be 7 × 10(-15) GeV with an electron, and 3 × 10(-8) GeV with a proton.

John J, Sulak L, Alimena J, Bhattacharya S, Christopher G, Cutts D, Demiragli Z, Ferapontov A, Garabedian A, Heintz U, Jabeen S, Kukartsev G, Laird E, Landsberg G, Luk M, Narain M, Segala M, Sinthuprasith T, Speer T, Swanson J, Breedon R, Breto G, Calderon De La Barca Sanchez M, Chauhan S, Chertok M, Conway J, Conway R, Cox PT, Erbacher R, Gardner M, Ko W, Kopecky A, Lander R, Miceli T, Mulhearn M, Pellett D, Pilot J, Ricci-Tam F, Rutherford B, Searle M, Shalhout S, Smith J, Squires M, Tripathi M, Wilbur S, Yohay R, Andreev V, Cline D, Cousins R, Erhan S, Everaerts P, Farrell C, Felcini M, Hauser J, Ignatenko M, Jarvis C, Rakness G, Takasugi E, Valuev V, Weber M, Babb J, Clare R, Ellison J, Gary JW, Hanson G, Heilman J, Jandir P, Lacroix F, Liu H, Long OR, Luthra A, Malberti M, Nguyen H, Shrinivas A, Sturdy J, Sumowidagdo S, Wimpenny S, Andrews W, Branson JG, Cerati GB, Cittolin S, D’Agnolo RT, Evans D, Holzner A, Kelley R, Kovalskyi D, Lebourgeois M, Letts J, Macneill I, Padhi S, Palmer C, Pieri M, Sani M, Sharma V, Simon S, Sudano E, Tadel M, Tu Y, Vartak A, Wasserbaech S, Würthwein F, Yagil A, Yoo J, Barge D, Bradmiller-Feld J, Campagnari C, Danielson T, Dishaw A, Flowers K, Franco Sevilla M, Geffert P, George C, Golf F, Incandela J, Justus C, Magaña Villalba R, Mccoll N, Pavlunin V, Richman J, Rossin R, Stuart D, To W, West C, Apresyan A, Bornheim A, Bunn J, Chen Y, Di Marco E, Duarte J, Kcira D, Mott A, Newman HB, Pena C, Rogan C, Spiropulu M, Timciuc V, Wilkinson R, Xie S, Zhu RY, Azzolini V, Calamba A, Carroll R, Ferguson T, Iiyama Y, Jang DW, Paulini M, Russ J, Vogel H, Vorobiev I, Cumalat JP, Drell BR, Ford WT, Gaz A, Luiggi Lopez E, Nauenberg U, Smith JG, Stenson K, Ulmer KA, Wagner SR, Alexander J, Chatterjee A, Chu J, Eggert N, Gibbons LK, Hopkins W, Khukhunaishvili A, Kreis B, Mirman N, Nicolas Kaufman G, Patterson JR, Ryd A, Salvati E, Sun W, Teo WD, Thom J, Thompson J, Tucker J, Weng Y, Winstrom L, Wittich P, Winn D, Abdullin S, Albrow M, Anderson 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Rinkevicius A, Shchutska L, Skhirtladze N, Snowball M, Yelton J, Zakaria M, Gaultney V, Hewamanage S, Linn S, Markowitz P, Martinez G, Rodriguez JL, Adams T, Askew A, Bochenek J, Chen J, Diamond B, Haas J, Hagopian S, Hagopian V, Johnson KF, Prosper H, Veeraraghavan V, Weinberg M, Baarmand MM, Dorney B, Hohlmann M, Kalakhety H, Yumiceva F, Adams MR, Apanasevich L, Bazterra VE, Betts RR, Bucinskaite I, Cavanaugh R, Evdokimov O, Gauthier L, Gerber CE, Hofman DJ, Khalatyan S, Kurt P, Moon DH, O’Brien C, Silkworth C, Turner P, Varelas N, Akgun U, Albayrak EA, Bilki B, Clarida W, Dilsiz K, Duru F, Haytmyradov M, Merlo JP, Mermerkaya H, Mestvirishvili A, Moeller A, Nachtman J, Ogul H, Onel Y, Ozok F, Penzo A, Rahmat R, Sen S, Tan P, Tiras E, Wetzel J, Yetkin T, Yi K, Barnett BA, Blumenfeld B, Bolognesi S, Fehling D, Gritsan AV, Maksimovic P, Martin C, Swartz M, Baringer P, Bean A, Benelli G, Gray J, Kenny RP, Murray M, Noonan D, Sanders S, Sekaric J, Stringer R, Wang Q, Wood JS, Barfuss AF, Chakaberia I, Ivanov A, Khalil S, Makouski M, Maravin Y, Saini LK, Shrestha S, Svintradze I, Gronberg J, Lange D, Rebassoo F, Wright D, Baden A, Calvert B, Eno SC, Gomez JA, Hadley NJ, Kellogg RG, Kolberg T, Lu Y, Marionneau M, Mignerey AC, Pedro K, Skuja A, Temple J, Tonjes MB, Tonwar SC, Apyan A, Barbieri R, Bauer G, Busza W, Cali IA, Chan M, Di Matteo L, Dutta V, Gomez Ceballos G, Goncharov M, Gulhan D, Klute M, Lai YS, Lee YJ, Levin A, Luckey PD, Ma T, Paus C, Ralph D, Roland C, Roland G, Stephans GSF, Stöckli F, Sumorok K, Velicanu D, Veverka J, Wyslouch B, Yang M, Yoon AS, Zanetti M, Zhukova V, Dahmes B, De Benedetti A, Gude A, Kao SC, Klapoetke K, Kubota Y, Mans J, Pastika N, Rusack R, Singovsky A, Tambe N, Turkewitz J, Acosta JG, Cremaldi LM, Kroeger R, Oliveros S, Perera L, Sanders DA, Summers D, Avdeeva E, Bloom K, Bose S, Claes DR, Dominguez A, Gonzalez Suarez R, Keller J, Knowlton D, Kravchenko I, Lazo-Flores J, Malik S, Meier F, Snow GR, Dolen J, Godshalk A, Iashvili I, 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Krutelyov V, Montalvo R, Osipenkov I, Pakhotin Y, Perloff A, Roe J, Rose A, Safonov A, Sakuma T, Suarez I, Tatarinov A, Toback D, Akchurin N, Cowden C, Damgov J, Dragoiu C, Dudero PR, Faulkner J, Kovitanggoon K, Kunori S, Lee SW, Libeiro T, Volobouev I, Appelt E, Delannoy AG, Greene S, Gurrola A, Johns W, Maguire C, Mao Y, Melo A, Sharma M, Sheldon P, Snook B, Tuo S, Velkovska J, Arenton MW, Boutle S, Cox B, Francis B, Goodell J, Hirosky R, Ledovskoy A, Li H, Lin C, Neu C, Wood J, Gollapinni S, Harr R, Karchin PE, Kottachchi Kankanamge Don C, Lamichhane P, Belknap DA, Borrello L, Carlsmith D, Cepeda M, Dasu S, Duric S, Friis E, Grothe M, Hall-Wilton R, Herndon M, Hervé A, Klabbers P, Klukas J, Lanaro A, Lazaridis C, Levine A, Loveless R, Mohapatra A, Ojalvo I, Perry T, Pierro GA, Polese G, Ross I, Sarangi T, Savin A, Smith WH, Woods N. Search for invisible decays of Higgs bosons in the vector boson fusion and associated ZH production modes

A search for invisible decays of Higgs bosons is performed using the vector boson fusion and associated ZH production modes. In the ZH mode, the Z boson is required to decay to a pair of charged leptons or a [Formula: see text] quark pair. The searches use the 8 [Formula: see text] pp collision dataset collected by the CMS detector at the LHC, corresponding to an integrated luminosity of up to 19.7 [Formula: see text]. Certain channels include data from 7 [Formula: see text] collisions corresponding to an integrated luminosity of 4.9 [Formula: see text]. The searches are sensitive to non-standard-model invisible decays of the recently observed Higgs boson, as well as additional Higgs bosons with similar production modes and large invisible branching fractions. In all channels, the observed data are consistent with the expected standard model backgrounds. Limits are set on the production cross section times invisible branching fraction, as a function of the Higgs boson mass, for the vector boson fusion and ZH production modes. By combining all channels, and assuming standard model Higgs boson cross sections and acceptances, the observed (expected) upper limit on the invisible branching fraction at [Formula: see text] [Formula: see text] is found to be 0.58 (0.44) at 95 % confidence level. We interpret this limit in terms of a Higgs-portal model of dark matter interactions.

Search for low-mass weakly interacting massive particles with SuperCDMS

We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg days was analyzed for WIMPs with mass <30  GeV/c(2), with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2×10(-42)  cm(2) at 8  GeV/c(2). This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses <6  GeV/c(2).

Supersymmetric exotic decays of the 125 GeV Higgs boson

We reveal a set of novel decay topologies for the 125 GeV Higgs boson in supersymmetry which are initiated by its decay into a pair of neutralinos, and discuss their collider search strategies. This category of exotic Higgs decays is characterized by the collider signature: visible objects+E_{T}, with E_{T} dominantly arising from escaping dark matter particles. Their benchmark arises naturally in the Peccei-Quinn symmetry limit of the minimal supersymmetric standard model singlet extensions, which is typified by the coexistence of three light particles: singletlike scalar h_{1} and pseudoscalar a_{1}, and singlinolike neutralino χ_{1}, all with masses of ≲10  GeV, and the generic suppression of the exotic decays of the 125 GeV Higgs boson h_{2}→h_{1}h_{1}, a_{1}a_{1} and χ_{1}χ_{1}, however. As an illustration, we study the decay topology: h_{2}→χ_{1}χ_{2}, where the binolike χ_{2} decays to h_{1}χ_{1} or a_{1}χ_{1}, and h_{1}/a_{1}→ff[over ¯], with ff[over ¯]=μ^{+}μ^{-}, bb[over ¯]. In the dimuon case (m_{h_{1}/a_{1}}∼1  GeV), a statistical sensitivity of S/sqrt[B]>6σ can be achieved easily at the 8 TeV LHC, assuming σ(pp→Wh_{2})/σ(pp→Wh_{SM})Br(h_{2}→μ^{+}μ^{-}χ_{1}χ_{1})=0.1. In the bb[over ¯] case (m_{h_{1}/a_{1}}∼45  GeV), 600  fb^{-1} data at the 14 TeV LHC can lead to a statistical sensitivity of S/sqrt[B]>5σ, assuming σ(pp→Zh_{2})/σ(pp→Zh_{SM})Br(h_{2}→bb[over ¯]χ_{1}χ_{1})=0.5. These exotic decays open a new avenue for exploring new physics couplings with the 125 GeV Higgs boson at colliders.