Search for dark matter in events with a hadronically decaying W or Z boson and missing transverse momentum in pp collisions at √s=8 TeV with the ATLAS detector

Nuclear structure opportunities with GeV radioactive beams at FAIR

The Facility for Antiproton and Ion Research (FAIR) is in its final construction stage next to the campus of the Gesellschaft für Schwerionenforschung Helmholtzzentrum for heavy-ion research in Darmstadt, Germany. Once it starts its operation, it will be the main nuclear physics research facility in many basic sciences and their applications in Europe for the coming decades. Owing to the ability of the new fragment separator, Super-FRagment Separator, to produce high-intensity radioactive ion beams in the energy range up to about 2 GeV/nucleon, these can be used in various nuclear reactions. This opens a unique opportunity for various nuclear structure studies across a range of fields and scales: from low-energy physics via the investigation of multi-neutron systems and halos to high-density nuclear matter and the equation of state, following heavy-ion collisions, fission and study of short-range correlations in nuclei and hypernuclei. The newly developed reactions with relativistic radioactive beams (R3B) set up at FAIR would be the most suitable and versatile for such studies. An overview of highlighted physics cases foreseen at R3B is given, along with possible future opportunities, at FAIR. This article is part of the theme issue 'The liminal position of Nuclear Physics: from hadrons to neutron stars'.

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.

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to bb[over ¯] Using 36 fb^{-1} of pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector

Several extensions of the standard model predict associated production of dark-matter particles with a Higgs boson. Such processes are searched for in final states with missing transverse momentum and a Higgs boson decaying to a bb[over ¯] pair with the ATLAS detector using 36.1  fb^{-1} of pp collisions at a center-of-mass energy of 13 TeV at the LHC. The observed data are in agreement with the standard model predictions and limits are placed on the associated production of dark-matter particles and a Higgs boson.

Search for Dark Matter and Supersymmetry with a Compressed Mass Spectrum in the Vector Boson Fusion Topology in Proton-Proton Collisions at sqrt[s]=8 TeV

A first search for pair production of dark matter candidates through vector boson fusion in proton-proton collisions at sqrt[s]=8  TeV is performed with the CMS detector. The vector boson fusion topology enhances missing transverse momentum, providing a way to probe supersymmetry, even in the case of a compressed mass spectrum. The data sample corresponds to an integrated luminosity of 18.5  fb^{-1}, recorded by the CMS experiment. The observed dijet mass spectrum is consistent with the standard model expectation. In an effective field theory, dark matter masses are explored as a function of contact interaction strength. The most stringent limit on bottom squark production with mass below 315 GeV is also reported, assuming a 5 GeV mass difference with respect to the lightest neutralino.

Search for Dark Matter in Events with Missing Transverse Momentum and a Higgs Boson Decaying to Two Photons in pp Collisions at sqrt[s]=8 TeV with the ATLAS Detector

Results of a search for new phenomena in events with large missing transverse momentum and a Higgs boson decaying to two photons are reported. Data from proton-proton collisions at a center-of-mass energy of 8 TeV and corresponding to an integrated luminosity of 20.3 fb^{-1} have been collected with the ATLAS detector at the LHC. The observed data are well described by the expected standard model backgrounds. Upper limits on the cross section of events with large missing transverse momentum and a Higgs boson candidate are also placed. Exclusion limits are presented for models of physics beyond the standard model featuring dark-matter candidates.

Search for invisible decays of the Higgs boson produced in association with a hadronically decaying vector boson in pp collisions at [Formula: see text] TeV with the ATLAS detector

A search for Higgs boson decays to invisible particles is performed using 20.3 [Formula: see text] of pp collision data at a centre-of-mass energy of 8 TeV recorded by the ATLAS detector at the Large Hadron Collider. The process considered is Higgs boson production in association with a vector boson ([Formula: see text] or Z) that decays hadronically, resulting in events with two or more jets and large missing transverse momentum. No excess of candidates is observed in the data over the background expectation. The results are used to constrain VH production followed by H decaying to invisible particles for the Higgs boson mass range [Formula: see text] GeV. The 95 % confidence-level observed upper limit on [Formula: see text] varies from 1.6 pb at 115 GeV to 0.13 pb at 300 GeV. Assuming Standard Model production and including the [Formula: see text] contribution as signal, the results also lead to an observed upper limit of 78 % at 95 % confidence level on the branching ratio of Higgs bosons decays to invisible particles at a mass of 125 GeV.

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.

Dark-matter decay as a complementary probe of multicomponent dark sectors

In single-component theories of dark matter, the 2→2 amplitudes for dark-matter production, annihilation, and scattering can be related to each other through various crossing symmetries. The detection techniques based on these processes are thus complementary. However, multicomponent theories exhibit an additional direction for dark-matter complementarity: the possibility of dark-matter decay from heavier to lighter components. We discuss how this new detection channel may be correlated with the others, and demonstrate that the enhanced complementarity which emerges can be an important ingredient in probing and constraining the parameter spaces of such models.

Bounds on invisible Higgs boson decays extracted from LHC ttH production data

We present an upper bound on the branching fraction of the Higgs boson to invisible particles by recasting a CMS Collaboration search for stop quarks decaying to tt + E(T)(miss). The observed (expected) bound, BF(H → inv.) < 0.40(0.65) at 95% C.L., is the strongest direct limit to date, benefiting from a downward fluctuation in the CMS data in that channel. In addition, we combine this new constraint with existing published constraints to give an observed (expected) bound of BF(H → inv.) < 0.40(0.40) at 95% C.L., and we show some of the implications for theories of dark matter which communicate through the Higgs portal.

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 J, Apollinari G, Bauerdick LAT, Beretvas A, Berryhill J, Bhat PC, Burkett K, Butler JN, Chetluru V, Cheung HWK, Chlebana F, Cihangir S, Elvira VD, Fisk I, Freeman J, Gao Y, Gottschalk E, Gray L, Green D, Grünendahl S, Gutsche O, Hanlon J, Hare D, Harris RM, Hirschauer J, Hooberman B, Jindariani S, Johnson M, Joshi U, Kaadze K, Klima B, Kwan S, Linacre J, Lincoln D, Lipton R, Liu T, Lykken J, Maeshima K, Marraffino JM, Martinez Outschoorn VI, Maruyama S, Mason D, McBride P, Mishra K, Mrenna S, Musienko Y, Nahn S, Newman-Holmes C, O’Dell V, Prokofyev O, Ratnikova N, Sexton-Kennedy E, Sharma S, Soha A, Spalding WJ, Spiegel L, Taylor L, Tkaczyk S, Tran NV, Uplegger L, Vaandering EW, Vidal R, Whitbeck A, Whitmore J, Wu W, Yang F, Yun JC, Acosta D, Avery P, Bourilkov D, Cheng T, Das S, De Gruttola M, Di Giovanni GP, Dobur D, Field RD, Fisher M, Fu Y, Furic IK, Hugon J, Kim B, Konigsberg J, Korytov A, Kropivnitskaya A, Kypreos T, Low JF, Matchev K, Milenovic P, Mitselmakher G, Muniz L, 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, Jain S, Kharchilava A, Kumar A, Rappoccio S, Alverson G, Barberis E, Baumgartel D, Chasco M, Haley J, Massironi A, Nash D, Orimoto T, Trocino D, Wang RJ, Wood D, Zhang J, Anastassov A, Hahn KA, Kubik A, Lusito L, Mucia N, Odell N, Pollack B, Pozdnyakov A, Schmitt M, Stoynev S, Sung K, Velasco M, Won S, Berry D, Brinkerhoff A, Chan KM, Drozdetskiy A, Hildreth M, Jessop C, Karmgard DJ, Kellams N, Kolb J, Lannon K, Luo W, Lynch S, Marinelli N, Morse DM, Pearson T, Planer M, Ruchti R, Slaunwhite J, Valls N, Wayne M, Wolf M, Woodard A, Antonelli L, Bylsma B, Durkin LS, Flowers S, Hill C, Hughes R, Kotov K, Ling TY, Puigh D, Rodenburg M, Smith G, Vuosalo C, Winer BL, Wolfe H, Wulsin HW, Berry E, Elmer P, Halyo V, Hebda P, Hunt A, Jindal P, Koay SA, Lujan P, Marlow D, Medvedeva T, Mooney M, Olsen J, Piroué P, Quan X, Raval A, Saka H, Stickland D, Tully C, Werner JS, Zenz SC, Zuranski A, Brownson E, Lopez A, Mendez H, Ramirez Vargas JE, Alagoz E, Benedetti D, Bolla G, Bortoletto D, De Mattia M, Everett A, Hu Z, Jha MK, Jones M, Jung K, Kress M, Leonardo N, Lopes Pegna D, Maroussov V, Merkel P, Miller DH, Neumeister N, Radburn-Smith BC, Shipsey I, Silvers D, Svyatkovskiy A, Wang F, Xie W, Xu L, Yoo HD, Zablocki J, Zheng Y, Parashar N, Stupak J, Adair A, Akgun B, Ecklund KM, Geurts FJM, Li W, Michlin B, Padley BP, Redjimi R, Roberts J, Zabel J, Betchart B, Bodek A, Covarelli R, de Barbaro P, Demina R, Eshaq Y, Ferbel T, Garcia-Bellido A, Goldenzweig P, Han J, Harel A, Miner DC, Petrillo G, Vishnevskiy D, Zielinski M, Bhatti A, Ciesielski R, Demortier L, Goulianos K, Lungu G, Malik S, Mesropian C, Arora S, Barker A, Chou JP, Contreras-Campana C, Contreras-Campana E, Duggan D, Ferencek D, Gershtein Y, Gray R, Halkiadakis E, Hidas D, Lath A, Panwalkar S, Park M, Patel R, Rekovic V, Robles J, Salur S, Schnetzer S, Seitz C, Somalwar S, Stone R, Thomas S, Thomassen P, Walker M, Rose K, Spanier S, Yang ZC, York A, Bouhali O, Eusebi R, Flanagan W, Gilmore J, Kamon T, Khotilovich V, 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.

Genetic variants associated with severe retinopathy of prematurity in extremely low birth weight infants

PURPOSE

To determine genetic variants associated with severe retinopathy of prematurity (ROP) in a candidate gene cohort study of US preterm infants.

METHODS

Preterm infants in the discovery cohort were enrolled through the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network, and those in the replication cohort were from the University of Iowa. All infants were phenotyped for ROP severity. Because of differences in the durations of enrollment between cohorts, severe ROP was defined as threshold disease in the discovery cohort and as threshold disease or type 1 ROP in the replication cohort. Whole genome amplified DNA from stored blood spot samples from the Neonatal Research Network biorepository was genotyped using an Illumina GoldenGate platform for candidate gene single nucleotide polymorphisms (SNPs) involving angiogenic, developmental, inflammatory, and oxidative pathways. Three analyses were performed to determine significant epidemiologic variables and SNPs associated with levels of ROP severity. Analyses controlled for multiple comparisons, ancestral eigenvalues, family relatedness, and significant epidemiologic variables. Single nucleotide polymorphisms significantly associated with ROP severity from the discovery cohort were analyzed in the replication cohort and in meta-analysis.

RESULTS

Eight hundred seventeen infants in the discovery cohort and 543 in the replication cohort were analyzed. Severe ROP occurred in 126 infants in the discovery and in 14 in the replication cohort. In both cohorts, ventilation days and seizure occurrence were associated with severe ROP. After controlling for significant factors and multiple comparisons, two intronic SNPs in the gene BDNF (rs7934165 and rs2049046, P < 3.1 × 10(-5)) were associated with severe ROP in the discovery cohort and were not associated with severe ROP in the replication cohort. However, when the cohorts were analyzed together in an exploratory meta-analysis, rs7934165 increased in associated significance with severe ROP (P = 2.9 × 10(-7)).

CONCLUSIONS

Variants in BDNF encoding brain-derived neurotrophic factor were associated with severe ROP in a large candidate gene study of infants with threshold ROP.