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

Interpretation of Neutral Charm Mesons near Threshold as Unparticles

The existence of the X(3872) resonance extremely close to the D^{*0}D[over ¯]^{0} threshold implies that neutral charm mesons have an approximate nonrelativistic conformal symmetry. Systems consisting of these mesons with small kinetic energies produced in a short-distance reaction are unparticles in the sense that they can be created by operators with definite scaling dimensions in a nonrelativistic conformal field theory. There is a scaling region in which their energy distribution has power-law behavior with an exponent determined by the scaling dimension of the operator. The unparticle associated with two neutral charm mesons produces a peak in the recoil momentum spectrum of K^{±} in inclusive decays of B^{±} that has been observed. The scaling dimensions of the unparticles associated with three neutral charm mesons are calculated. They can be determined experimentally by measuring the invariant mass distributions for XD^{0} or XD^{*0} in inclusive prompt production at the Large Hadron Collider.

Unnuclear physics: Conformal symmetry in nuclear reactions

We investigate a nonrelativistic version of Georgi's "unparticle physics." We define the unnucleus as a field in a nonrelativistic conformal field theory. Such a field is characterized by a mass and a conformal dimension. We then consider the formal problem of scatterings to a final state consisting of a particle and an unnucleus and show that the differential cross-section, as a function of the recoil energy received by the particle, has a power-law singularity near the maximal recoil energy, where the power is determined by the conformal dimension of the unnucleus. We argue that unlike the relativistic unparticle, which remains a hypothetical object, the unnucleus is realized, to a good approximation, in nuclear reactions involving emission of a few neutrons, when the energy of the final-state neutrons in their center-of-mass frame lies in the range between about 0.1 MeV and 5 MeV. Combining this observation with the known universal properties of fermions at unitarity in a harmonic trap, we predict a power-law behavior of an inclusive cross-section in this kinematic regime. We verify our predictions with previous effective field theory and model calculations of the 6He[Formula: see text], 3H[Formula: see text], and 3H[Formula: see text] reactions and discuss opportunities to measure unnuclei at radioactive beam facilities.

Explaining the XENON1T Excess with Luminous Dark Matter

We show that the excess in electron recoil events seen by the XENON1T experiment can be explained by a relatively low-mass luminous dark matter candidate. The dark matter scatters inelastically in the detector (or the surrounding rock) to produce a heavier dark state with a ∼2-3  keV mass splitting. This heavier state then decays within the detector, producing a peak in the electron recoil spectrum that is a good fit to the observed excess. We comment on the ability of future direct detection experiments to differentiate this model from other "beyond the standard model" scenarios and from possible tritium backgrounds, including the use of diurnal modulation, multichannel signals, etc., as possible distinguishing features of this scenario.

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}.

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}.

Search for Boosted Dark Matter Interacting with Electrons in Super-Kamiokande

A search for boosted dark matter using 161.9 kt yr of Super-Kamiokande IV data is presented. We search for an excess of elastically scattered electrons above the atmospheric neutrino background, with a visible energy between 100 MeV and 1 TeV, pointing back to the Galactic center or the Sun. No such excess is observed. Limits on boosted dark matter event rates in multiple angular cones around the Galactic center and Sun are calculated. Limits are also calculated for a baseline model of boosted dark matter produced from cold dark matter annihilation or decay. This is the first experimental search for boosted dark matter from the Galactic center or the Sun interacting in a terrestrial detector.

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.

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Trevisani N, Vila I, Cortabitarte RV, Abbaneo D, Akgun B, Auffray E, Baillon P, Ball AH, Barney D, Bendavid J, Bianco M, Bloch P, Bocci A, Botta C, Camporesi T, Castello R, Cepeda M, Cerminara G, Chapon E, Chen Y, d’Enterria D, Dabrowski A, Daponte V, David A, De Gruttola M, De Roeck A, Deelen N, Dobson M, du Pree T, Dünser M, Dupont N, Elliott-Peisert A, Everaerts P, Fallavollita F, Franzoni G, Fulcher J, Funk W, Gigi D, Gilbert A, Gill K, Glege F, Gulhan D, Harris P, Hegeman J, Innocente V, Jafari A, Janot P, Karacheban O, Kieseler J, Knünz V, Kornmayer A, Kortelainen MJ, Krammer M, Lange C, Lecoq P, Lourenço C, Lucchini MT, Malgeri L, Mannelli M, Martelli A, Meijers F, Merlin JA, Mersi S, Meschi E, Milenovic P, Moortgat F, Mulders M, Neugebauer H, Ngadiuba J, Orfanelli S, Orsini L, Pape L, Perez E, Peruzzi M, Petrilli A, Petrucciani G, Pfeiffer A, Pierini M, Rabady D, Racz A, Reis T, Rolandi G, Rovere M, Sakulin H, Schäfer C, Schwick C, Seidel M, Selvaggi M, Sharma A, Silva P, Sphicas P, Stakia A, Steggemann J, Stoye M, Tosi M, Treille D, Triossi A, Tsirou A, Veckalns V, Verweij M, Zeuner WD, Bertl W, Caminada L, Deiters K, Erdmann W, Horisberger R, Ingram Q, Kaestli HC, Kotlinski D, Langenegger U, Rohe T, Wiederkehr SA, Backhaus M, Bäni L, Berger P, Bianchini L, Casal B, Dissertori G, Dittmar M, Donegà M, Dorfer C, Grab C, Heidegger C, Hits D, Hoss J, Kasieczka G, Klijnsma T, Lustermann W, Mangano B, Marionneau M, Meinhard MT, Meister D, Micheli F, Musella P, Nessi-Tedaldi F, Pandolfi F, Pata J, Pauss F, Perrin G, Perrozzi L, Quittnat M, Reichmann M, Sanz Becerra DA, Schönenberger M, Shchutska L, Tavolaro VR, Theofilatos K, Olsson MLV, Wallny R, Zhu DH, Aarrestad TK, Amsler C, Canelli MF, De Cosa A, Del Burgo R, Donato S, Galloni C, Hreus T, Kilminster B, Pinna D, Rauco G, Robmann P, Salerno D, Schweiger K, Seitz C, Takahashi Y, Zucchetta A, Candelise V, Chang YH, Cheng KY, Doan TH, Jain S, Khurana R, Kuo CM, Lin W, Pozdnyakov A, Yu SS, Kumar A, Chang P, Chao Y, Chen KF, Chen PH, Fiori F, Hou WS, Hsiung Y, Liu YF, Lu RS, Paganis E, Psallidas A, Steen A, Tsai JF, Asavapibhop B, Kovitanggoon K, Singh G, Srimanobhas N, Bat A, Boran F, Cerci S, Damarseckin S, Demiroglu ZS, Dozen C, Dumanoglu I, Girgis S, Gokbulut G, Guler Y, Hos I, Kangal EE, Kara O, Topaksu AK, Kiminsu U, Oglakci M, Onengut G, Ozdemir K, Cerci DS, Tali B, Tok UG, Turkcapar S, Zorbakir IS, Zorbilmez C, Karapinar G, Ocalan K, Yalvac M, Zeyrek M, Gülmez E, Kaya M, Kaya O, Tekten S, Yetkin EA, Agaras MN, Atay S, Cakir A, Cankocak K, Köseoglu I, Grynyov B, Levchuk L, Ball F, Beck L, Brooke JJ, Burns D, Clement E, Cussans D, Davignon O, Flacher H, Goldstein J, Heath GP, Heath HF, Kreczko L, Newbold DM, Paramesvaran S, Sakuma T, Seif El Nasr-storey S, Smith D, Smith VJ, Bell KW, Belyaev A, Brew C, Brown RM, Calligaris L, Cieri D, Cockerill DJA, Coughlan JA, Harder K, Harper S, Linacre J, Olaiya E, Petyt D, Shepherd-Themistocleous CH, Thea A, Tomalin IR, Williams T, Auzinger G, Bainbridge R, Borg J, Breeze S, Buchmuller O, Bundock A, Casasso S, Citron M, Colling D, Corpe L, Dauncey P, Davies G, De Wit A, Della Negra M, Di Maria R, Elwood A, Haddad Y, Hall G, Iles G, James T, Lane R, Laner C, Lyons L, Magnan AM, Malik S, Mastrolorenzo L, Matsushita T, Nash J, Nikitenko A, Palladino V, Pesaresi M, Raymond DM, Richards A, Rose A, Scott E, Seez C, Shtipliyski A, Summers S, Tapper A, Uchida K, Acosta MV, Virdee T, Wardle N, Winterbottom D, Wright J, Zenz SC, Cole JE, Hobson PR, Khan A, Kyberd P, Reid ID, Teodorescu L, Zahid S, Borzou A, Call K, Dittmann J, Hatakeyama K, Liu H, Pastika N, Smith C, Bartek R, Dominguez A, Buccilli A, Cooper SI, Henderson C, Rumerio P, West C, Arcaro D, Avetisyan A, Bose T, Gastler D, Rankin D, Richardson C, Rohlf J, Sulak L, Zou D, Benelli G, Cutts D, Garabedian A, Hadley M, Hakala J, Heintz U, Hogan JM, Kwok KHM, Laird E, Landsberg G, Lee J, Mao Z, Narain M, Pazzini J, Piperov S, Sagir S, Syarif R, Yu D, Band R, Brainerd C, Breedon R, Burns D, De La Barca Sanchez MC, Chertok M, Conway J, Conway R, Cox PT, Erbacher R, Flores C, Funk G, Ko W, Lander R, Mclean C, Mulhearn M, Pellett D, Pilot J, Shalhout S, Shi M, Smith J, Stolp D, Tos K, Tripathi M, Wang Z, Bachtis M, Bravo C, Cousins R, Dasgupta A, Florent A, Hauser J, Ignatenko M, Mccoll N, Regnard S, Saltzberg D, Schnaible C, Valuev V, Bouvier E, Burt K, Clare R, Ellison J, Gary JW, Shirazi SMAG, Hanson G, Heilman J, Karapostoli G, Kennedy E, Lacroix F, Long OR, Negrete MO, Paneva MI, Si W, Wang L, Wei H, Wimpenny S, Yates BR, Branson JG, Cittolin S, Derdzinski M, Gerosa R, Gilbert D, Hashemi B, Holzner A, Klein D, Kole G, Krutelyov V, Letts J, Masciovecchio M, Olivito D, Padhi S, Pieri M, Sani M, Sharma V, Tadel M, Vartak A, Wasserbaech S, Wood J, Würthwein F, Yagil A, Della Porta GZ, Amin N, Bhandari R, Bradmiller-Feld J, Campagnari C, Dishaw A, Dutta V, Franco Sevilla M, Gouskos L, Heller R, Incandela J, Ovcharova A, Qu H, Richman J, Stuart D, Suarez I, Yoo J, Anderson D, Bornheim A, Lawhorn JM, Newman HB, Nguyen TQ, Pena C, Spiropulu M, Vlimant JR, Xie S, Zhang Z, Zhu RY, Andrews MB, Ferguson T, Mudholkar T, Paulini M, Russ J, Sun M, Vogel H, Vorobiev I, Weinberg M, Cumalat JP, Ford WT, Jensen F, Johnson A, Krohn M, Leontsinis S, Mulholland T, Stenson K, Wagner SR, Alexander J, Chaves J, Chu J, Dittmer S, Mcdermott K, Mirman N, Patterson JR, Quach D, Rinkevicius A, Ryd A, Skinnari L, Soffi L, Tan SM, Tao Z, Thom J, Tucker J, Wittich P, Zientek M, Abdullin S, Albrow M, Alyari M, Apollinari G, Apresyan A, Apyan A, Banerjee S, Bauerdick LAT, Beretvas A, Berryhill J, Bhat PC, Bolla G, Burkett K, Butler JN, Canepa A, Cerati GB, Cheung HWK, Chlebana F, Cremonesi M, Duarte J, Elvira VD, Freeman J, Gecse Z, Gottschalk E, Gray L, Green D, Grünendahl S, Gutsche O, Harris RM, Hasegawa S, Hirschauer J, Hu Z, Jayatilaka B, Jindariani S, Johnson M, Joshi U, Klima B, Kreis B, Lammel S, Lincoln D, Lipton R, Liu M, Liu T, De Sá RL, Lykken J, Maeshima K, Magini N, Marraffino JM, Mason D, McBride P, Merkel P, Mrenna S, Nahn S, O’Dell V, Pedro K, Prokofyev O, Rakness G, Ristori L, Schneider B, Sexton-Kennedy E, Soha A, Spalding WJ, Spiegel L, Stoynev S, Strait J, Strobbe N, Taylor L, Tkaczyk S, Tran NV, Uplegger L, Vaandering EW, Vernieri C, Verzocchi M, Vidal R, Wang M, Weber HA, Whitbeck A, Acosta D, Avery P, Bortignon P, Bourilkov D, Brinkerhoff A, Carnes A, Carver M, Curry D, Field RD, Furic IK, Gleyzer SV, Joshi BM, Konigsberg J, Korytov A, Kotov K, Ma P, Matchev K, Mei H, Mitselmakher G, Shi K, Sperka D, Terentyev N, Thomas L, Wang J, Wang S, Yelton J, Joshi YR, Linn S, Markowitz P, Rodriguez JL, Ackert A, Adams T, Askew A, Hagopian S, Hagopian V, Johnson KF, Kolberg T, Martinez G, Perry T, Prosper H, Saha A, Santra A, Sharma V, Yohay R, Baarmand MM, Bhopatkar V, Colafranceschi S, Hohlmann M, Noonan D, Roy T, Yumiceva F, Adams MR, Apanasevich L, Berry D, Betts RR, Cavanaugh R, Chen X, Evdokimov O, Gerber CE, Hangal DA, Hofman DJ, Jung K, Kamin J, Gonzalez IDS, Tonjes MB, Trauger H, Varelas N, Wang H, Wu Z, Zhang J, Bilki B, Clarida W, Dilsiz K, Durgut S, Gandrajula RP, Haytmyradov M, Khristenko V, Merlo JP, Mermerkaya H, Mestvirishvili A, Moeller A, Nachtman J, Ogul H, Onel Y, Ozok F, Penzo A, Snyder C, Tiras E, Wetzel J, Yi K, Blumenfeld B, Cocoros A, Eminizer N, Fehling D, Feng L, Gritsan AV, Maksimovic P, Roskes J, Sarica U, Swartz M, Xiao M, You C, Al-bataineh A, Baringer P, Bean A, Boren S, Bowen J, Castle J, Khalil S, Kropivnitskaya A, Majumder D, Mcbrayer W, Murray M, Rogan C, Royon C, Sanders S, Schmitz E, Tapia Takaki JD, Wang Q, Ivanov A, Kaadze K, Maravin Y, Mohammadi A, Saini LK, Skhirtladze N, Rebassoo F, Wright D, Anelli C, Baden A, Baron O, Belloni A, Eno SC, Feng Y, Ferraioli C, Hadley NJ, Jabeen S, Jeng GY, Kellogg RG, Kunkle J, Mignerey AC, Ricci-Tam F, Shin YH, Skuja A, Tonwar SC, Abercrombie D, Allen B, Azzolini V, Barbieri R, Baty A, Bi R, Brandt S, Busza W, Cali IA, D’Alfonso M, Demiragli Z, Ceballos GG, Goncharov M, Hsu D, Hu M, Iiyama Y, Innocenti GM, Klute M, Kovalskyi D, Lee YJ, Levin A, Luckey PD, Maier B, Marini AC, Mcginn C, Mironov C, Narayanan S, Niu X, Paus C, Roland C, Roland G, Salfeld-Nebgen J, Stephans GSF, Tatar K, Velicanu D, Wang J, Wang TW, Wyslouch B, Benvenuti AC, Chatterjee RM, Evans A, Hansen P, Hiltbrand J, Kalafut S, Kubota Y, Lesko Z, Mans J, Nourbakhsh S, Ruckstuhl N, Rusack R, Turkewitz J, Wadud MA, Acosta JG, Oliveros S, Avdeeva E, Bloom K, Claes DR, Fangmeier C, Golf F, Suarez RG, Kamalieddin R, Kravchenko I, Monroy J, Siado JE, Snow GR, Stieger B, Dolen J, Godshalk A, Harrington C, Iashvili I, Nguyen D, Parker A, Rappoccio S, Roozbahani B, Alverson G, Barberis E, Freer C, Hortiangtham A, Massironi A, Morse DM, Orimoto T, De Lima RT, Trocino D, Wamorkar T, Wang B, Wisecarver A, Wood D, Bhattacharya S, Charaf O, Hahn KA, Mucia N, Odell N, Schmitt MH, Sung K, Trovato M, Velasco M, Bucci R, Dev N, Hildreth M, Anampa KH, Jessop C, Karmgard DJ, Kellams N, Lannon K, Li W, Loukas N, Marinelli N, Meng F, Mueller C, Musienko Y, Planer M, Reinsvold A, Ruchti R, Siddireddy P, Smith G, Taroni S, Wayne M, Wightman A, Wolf M, Woodard A, Alimena J, Antonelli L, Bylsma B, Durkin LS, Flowers S, Francis B, Hart A, Hill C, Ji W, Liu B, Luo W, Winer BL, Wulsin HW, Cooperstein S, Driga O, Elmer P, Hardenbrook J, Hebda P, Higginbotham S, Kalogeropoulos A, Lange D, Luo J, Marlow D, Mei K, Ojalvo I, Olsen J, Palmer C, Piroué P, Stickland D, Tully C, Malik S, Norberg S, Barker A, Barnes VE, Das S, Folgueras S, Gutay L, Jha MK, Jones M, Jung AW, Khatiwada A, Miller DH, Neumeister N, Peng CC, Qiu H, Schulte JF, Sun J, Wang F, Xiao R, Xie W, Cheng T, Parashar N, Stupak J, Chen Z, Ecklund KM, Freed S, Geurts FJM, Guilbaud M, Kilpatrick M, Li W, Michlin B, Padley BP, Roberts J, Rorie J, Shi W, Tu Z, Zabel J, Zhang A, Bodek A, de Barbaro P, Demina R, Duh YT, Ferbel T, Galanti M, Garcia-Bellido A, Han J, Hindrichs O, Khukhunaishvili A, Lo KH, Tan P, Verzetti M, Ciesielski R, Goulianos K, Mesropian C, Agapitos A, Chou JP, Gershtein Y, Espinosa TAG, Halkiadakis E, Heindl M, Hughes E, Kaplan S, Elayavalli RK, Kyriacou S, Lath A, Montalvo R, Nash K, Osherson M, Saka H, Salur S, Schnetzer S, Sheffield D, Somalwar S, Stone R, Thomas S, Thomassen P, Walker M, Delannoy AG, Heideman J, Riley G, Rose K, Spanier S, Thapa K, Bouhali O, Hernandez AC, Celik A, Dalchenko M, De Mattia M, Delgado A, Dildick S, Eusebi R, Gilmore J, Huang T, Kamon T, Mueller R, Pakhotin Y, Patel R, Perloff A, Perniè L, Rathjens D, Safonov A, Tatarinov A, Ulmer KA, Akchurin N, Damgov J, De Guio F, Dudero PR, Faulkner J, Gurpinar E, Kunori S, Lamichhane K, Lee SW, Libeiro T, Mengke T, Muthumuni S, Peltola T, Undleeb S, Volobouev I, Wang Z, Greene S, Gurrola A, Janjam R, Johns W, Maguire C, Melo A, Ni H, Padeken K, Sheldon P, Tuo S, Velkovska J, Xu Q, Arenton MW, Barria P, Cox B, Hirosky R, Joyce M, Ledovskoy A, Li H, Neu C, Sinthuprasith T, Wang Y, Wolfe E, Xia F, Harr R, Karchin PE, Poudyal N, Sturdy J, Thapa P, Zaleski S, Brodski M, Buchanan J, Caillol C, Dasu S, Dodd L, Duric S, Gomber B, Grothe M, Herndon M, Hervé A, Hussain U, Klabbers P, Lanaro A, Levine A, Long K, Loveless R, Ruggles T, Savin A, Smith N, Smith WH, Taylor D, Woods N. Search for new physics in events with a leptonically decaying Z boson and a large transverse momentum imbalance in proton-proton collisions at s = 13 TeV

A search for new physics in events with a Z boson produced in association with large missing transverse momentum at the LHC is presented. The search is based on the 2016 data sample of proton-proton collisions recorded with the CMS experiment ats = 13 TeV , corresponding to an integrated luminosity of 35.9fb - 1 . The results of this search are interpreted in terms of a simplified model of dark matter production via spin-0 or spin-1 mediators, a scenario with a standard-model-like Higgs boson produced in association with the Z boson and decaying invisibly, a model of unparticle production, and a model with large extra spatial dimensions. No significant deviations from the background expectations are found, and limits are set on relevant model parameters, significantly extending the results previously achieved in this channel.

Quantum Forces from Dark Matter and Where to Find Them

We observe that sub-GeV dark matter (DM) induces Casimir-Polder forces between nucleons that can be accessed by experiments from nuclear to molecular scales. We calculate the nucleon-nucleon potentials arising in the DM effective theory and note that their main features are fixed by dimensional analysis and the optical theorem. Molecular spectroscopy and neutron scattering turn out be DM search experiments and are found to be complementary to nucleon-based DM direct detection. Existing data set limits on DM with mass up to ∼3-50  MeV and with effective interaction up to the O(10-100)  MeV scale, constraining a region typically difficult to reach for other experiments.

Thermal Dark Matter Below a MeV

We consider a class of models in which thermal dark matter is lighter than a MeV. If dark matter thermalizes with the standard model below the temperature of neutrino-photon decoupling, equilibration and freeze-out cool and heat the standard model bath comparably, alleviating constraints from measurements of the effective number of neutrino species. We demonstrate this mechanism in a model consisting of fermionic dark matter coupled to a light scalar mediator. Thermal dark matter can be as light as a few keV, while remaining compatible with existing cosmological and astrophysical observations. This framework motivates new experiments in the direct search for sub-MeV thermal dark matter and light force carriers.

Denis RD, Stabile A, Stamen R, Stamm S, Stanecka E, Stanek RW, Stanescu C, Stanitzki MM, Stapf BS, Stapnes S, Starchenko EA, Stark GH, Stark J, Stark SH, Staroba P, Starovoitov P, Stärz S, Staszewski R, Steinberg P, Stelzer B, Stelzer HJ, Stelzer-Chilton O, Stenzel H, Stewart GA, Stockton MC, Stoebe M, Stoicea G, Stolte P, Stonjek S, Stradling AR, Straessner A, Stramaglia ME, Strandberg J, Strandberg S, Strauss M, Strizenec P, Ströhmer R, Strom DM, Stroynowski R, Strubig A, Stucci SA, Stugu B, Styles NA, Su D, Su J, Suchek S, Sugaya Y, Suk M, Sulin VV, Sultan DMS, Sultansoy S, Sumida T, Sun S, Sun X, Suruliz K, Suster CJE, Sutton MR, Suzuki S, Svatos M, Swiatlowski M, Swift SP, Sykora I, Sykora T, Ta D, Tackmann K, Taenzer J, Taffard A, Tafirout R, Taiblum N, Takai H, Takashima R, Takasugi EH, Takeshita T, Takubo Y, Talby M, Talyshev AA, Tanaka J, Tanaka M, Tanaka R, Tanaka S, Tanioka R, Tannenwald BB, Tapia Araya S, Tapprogge S, Tarem S, Tartarelli GF, Tas P, Tasevsky M, Tashiro T, Tassi E, Tavares Delgado A, Tayalati Y, Taylor AC, Taylor GN, Taylor PTE, Taylor W, Teixeira-Dias P, Temple D, Ten Kate H, Teng PK, Teoh JJ, Tepel F, Terada S, Terashi K, Terron J, Terzo S, Testa M, Teuscher RJ, Theveneaux-Pelzer T, Thomas JP, Thomas-Wilsker J, Thompson PD, Thompson AS, Thomsen LA, Thomson E, Tibbetts MJ, Ticse Torres RE, Tikhomirov VO, Tikhonov YA, Timoshenko S, Tipton P, Tisserant S, Todome K, Todorova-Nova S, Tojo J, Tokár S, Tokushuku K, Tolley E, Tomlinson L, Tomoto M, Tompkins L, Toms K, Tong B, Tornambe P, Torrence E, Torres H, Torró Pastor E, Toth J, Touchard F, Tovey DR, Treado CJ, Trefzger T, Tresoldi F, Tricoli A, Trigger IM, Trincaz-Duvoid S, Tripiana MF, Trischuk W, Trocmé B, Trofymov A, Troncon C, Trottier-McDonald M, Trovatelli M, Truong L, Trzebinski M, Trzupek A, Tsang KW, Tseng JCL, Tsiareshka PV, Tsipolitis G, Tsirintanis N, Tsiskaridze S, Tsiskaridze V, Tskhadadze EG, Tsui KM, Tsukerman II, Tsulaia V, Tsuno S, Tsybychev D, Tu Y, Tudorache A, Tudorache V, Tulbure TT, Tuna AN, Tupputi SA, Turchikhin S, Turgeman D, Turk Cakir I, Turra R, Tuts PM, Ucchielli G, Ueda I, Ughetto M, Ukegawa F, Unal G, Undrus A, Unel G, Ungaro FC, Unno Y, Unverdorben C, Urban J, Urquijo P, Urrejola P, Usai G, Usui J, Vacavant L, Vacek V, Vachon B, Vaidya A, Valderanis C, Valdes Santurio E, Valentinetti S, Valero A, Valéry L, Valkar S, Vallier A, Valls Ferrer JA, Van Den Wollenberg W, van der Graaf H, van Gemmeren P, Van Nieuwkoop J, van Vulpen I, van Woerden MC, Vanadia M, Vandelli W, Vaniachine A, Vankov P, Vardanyan G, Vari R, Varnes EW, Varni C, Varol T, Varouchas D, Vartapetian A, Varvell KE, Vasquez JG, Vasquez GA, Vazeille F, Vazquez Schroeder T, Veatch J, Veeraraghavan V, Veloce LM, Veloso F, Veneziano S, Ventura A, Venturi M, Venturi N, Venturini A, Vercesi V, Verducci M, Verkerke W, Vermeulen AT, Vermeulen JC, Vetterli MC, Viaux Maira N, Viazlo O, Vichou I, Vickey T, Vickey Boeriu OE, Viehhauser GHA, Viel S, Vigani L, Villa M, Villaplana Perez M, Vilucchi E, Vincter MG, Vinogradov VB, Vishwakarma A, Vittori C, Vivarelli I, Vlachos S, Vlasak M, Vogel M, Vokac P, Volpi G, von der Schmitt H, von Toerne E, Vorobel V, Vorobev K, Vos M, Voss R, Vossebeld JH, Vranjes N, Vranjes Milosavljevic M, Vrba V, Vreeswijk M, Vuillermet R, Vukotic I, Wagner P, Wagner W, Wagner-Kuhr J, Wahlberg H, Wahrmund S, Wakabayashi J, Walder J, Walker R, Walkowiak W, Wallangen V, Wang C, Wang C, Wang F, Wang H, Wang H, Wang J, Wang J, Wang Q, Wang R, Wang SM, Wang T, Wang W, Wang W, Wang Z, Wanotayaroj C, Warburton A, Ward CP, Wardrope DR, Washbrook A, Watkins PM, Watson AT, Watson MF, Watts G, Watts S, Waugh BM, Webb AF, Webb S, Weber MS, Weber SW, Weber SA, Webster JS, Weidberg AR, Weinert B, Weingarten J, Weirich M, Weiser C, Weits H, Wells PS, Wenaus T, Wengler T, Wenig S, Wermes N, Werner MD, Werner P, Wessels M, Whalen K, Whallon NL, Wharton AM, White AS, White A, White MJ, White R, Whiteson D, Whitmore BW, Wickens FJ, Wiedenmann W, Wielers M, Wiglesworth C, Wiik-Fuchs LAM, Wildauer A, Wilk F, Wilkens HG, Williams HH, Williams S, Willis C, Willocq S, Wilson JA, Wingerter-Seez I, Winkels E, Winklmeier F, Winston OJ, Winter BT, Wittgen M, Wobisch M, Wolf TMH, Wolff R, Wolter MW, Wolters H, Wong VWS, Worm SD, Wosiek BK, Wotschack J, Wozniak KW, Wu M, Wu SL, Wu X, Wu Y, Wyatt TR, Wynne BM, Xella S, Xi Z, Xia L, Xu D, Xu L, Xu T, Yabsley B, Yacoob S, Yamaguchi D, Yamaguchi Y, Yamamoto A, Yamamoto S, Yamanaka T, Yamatani M, Yamauchi K, Yamazaki Y, Yan Z, Yang H, Yang H, Yang Y, Yang Z, Yao WM, Yap YC, Yasu Y, Yatsenko E, Yau Wong KH, Ye J, Ye S, Yeletskikh I, Yigitbasi E, Yildirim E, Yorita K, Yoshihara K, Young C, Young CJS, Yu J, Yu J, Yuen SPY, Yusuff I, Zabinski B, Zacharis G, Zaidan R, Zaitsev AM, Zakharchuk N, Zalieckas J, Zaman A, Zambito S, Zanzi D, Zeitnitz C, Zemaityte G, Zemla A, Zeng JC, Zeng Q, Zenin O, Ženiš T, Zerwas D, Zhang D, Zhang F, Zhang G, Zhang H, Zhang J, Zhang L, Zhang L, Zhang M, Zhang P, Zhang R, Zhang R, Zhang X, Zhang Y, Zhang Z, Zhao X, Zhao Y, Zhao Z, Zhemchugov A, Zhou B, Zhou C, Zhou L, Zhou M, Zhou M, Zhou N, Zhu CG, Zhu H, Zhu J, Zhu Y, Zhuang X, Zhukov K, Zibell A, Zieminska D, Zimine NI, Zimmermann C, Zimmermann S, Zinonos Z, Zinser M, Ziolkowski M, Živković L, Zobernig G, Zoccoli A, Zou R, zur Nedden M, Zwalinski L. Measurement of detector-corrected observables sensitive to the anomalous production of events with jets and large missing transverse momentum in p p collisions at s = 13 TeV using the ATLAS detector

Observables sensitive to the anomalous production of events containing hadronic jets and missing momentum in the plane transverse to the proton beams at the Large Hadron Collider are presented. The observables are defined as a ratio of cross sections, for events containing jets and large missing transverse momentum to events containing jets and a pair of charged leptons from the decay of a Z / γ ∗ boson. This definition minimises experimental and theoretical systematic uncertainties in the measurements. This ratio is measured differentially with respect to a number of kinematic properties of the hadronic system in two phase-space regions; one inclusive single-jet region and one region sensitive to vector-boson-fusion topologies. The data are found to be in agreement with the Standard Model predictions and used to constrain a variety of theoretical models for dark-matter production, including simplified models, effective field theory models, and invisible decays of the Higgs boson. The measurements use 3.2 fb- 1 of proton-proton collision data recorded by the ATLAS experiment at a centre-of-mass energy of 13  TeV and are fully corrected for detector effects, meaning that the data can be used to constrain new-physics models beyond those shown in this paper.

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.

Dark Matter Coannihilation with a Lighter Species

We propose a new thermal freeze-out mechanism for ultraheavy dark matter. Dark matter coannihilates with a lighter unstable species that is nearby in mass, leading to an annihilation rate that is exponentially enhanced relative to standard weakly interactive massive particles. This scenario destabilizes any potential dark matter candidate. In order to remain consistent with astrophysical observations, our proposal necessitates very long-lived states, motivating striking phenomenology associated with the late decays of ultraheavy dark matter, potentially as massive as the scale of grand unified theories, M_{GUT}∼10^{16}  GeV.

ALPs effective field theory and collider signatures

We study the leading effective interactions between the Standard Model fields and a generic singlet CP-odd (pseudo-) Goldstone boson. Two possible frameworks for electroweak symmetry breaking are considered: linear and non-linear. For the latter case, the basis of leading effective operators is determined and compared with that for the linear expansion. Associated phenomenological signals at colliders are explored for both scenarios, deriving new bounds and analyzing future prospects, including LHC and High Luminosity LHC sensitivities. Mono-Z, mono-W, W-photon plus missing energy and on-shell top final states are most promising signals expected in both frameworks. In addition, non-standard Higgs decays and mono-Higgs signatures are especially prominent and expected to be dominant in non-linear realisations.

Dark matter phenomenology of SM and enlarged Higgs sectors extended with vector-like leptons

We will investigate the scenario in which the Standard Model (SM) Higgs sector and its two-doublet extension (called the Two Higgs Doublet Model or 2HDM) are the "portal" for the interactions between the Standard Model and a fermionic Dark Matter (DM) candidate. The latter is the lightest stable neutral particle of a family of vector-like leptons (VLLs). We will provide an extensive overview of this scenario combining the constraints coming purely from DM phenomenology with more general constraints like Electroweak Precision Test (EWPT) as well as with collider searches. In the case that the new fermionic sector interacts with the SM Higgs sector, constraints from DM phenomenology force the new states to lie above the TeV scale. This requirement is relaxed in the case of 2HDM. Nevertheless, strong constraints coming from EWPTs and the Renormalization Group Equations (RGEs) limit the impact of VLFs on collider phenomenology.

Spin-Dependent Weakly-Interacting-Massive-Particle-Nucleon Cross Section Limits from First Data of PandaX-II Experiment

New constraints are presented on the spin-dependent weakly-interacting-massive-particle–- (WIMP-)nucleon interaction from the PandaX-II experiment, using a data set corresponding to a total exposure of 3.3×10^{4}  kg day. Assuming a standard axial-vector spin-dependent WIMP interaction with ^{129}Xe and ^{131}Xe nuclei, the most stringent upper limits on WIMP-neutron cross sections for WIMPs with masses above 10  GeV/c^{2} are set in all dark matter direct detection experiments. The minimum upper limit of 4.1×10^{-41}  cm^{2} at 90% confidence level is obtained for a WIMP mass of 40  GeV/c^{2}. This represents more than a factor of 2 improvement on the best available limits at this and higher masses. These improved cross-section limits provide more stringent constraints on the effective WIMP-proton and WIMP-neutron couplings.

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.

Confronting dark matter with the diphoton excess from a parent resonance decay

A diphoton excess with an invariant mass of about 750 GeV has been recently reported by both ATLAS and CMS experiments at LHC. While the simplest interpretation requires the resonant production of a 750 GeV (pseudo)scalar, here we consider an alternative setup, with an additional heavy parent particle which decays into a pair of 750 GeV resonances. This configuration improves the agreement between the 8 and 13 TeV data. Moreover, we include a dark matter candidate in the form of a Majorana fermion which interacts through the 750 GeV portal. The invisible decays of the light resonance help to suppress additional decay channels into Standard Model particles in association with the diphoton signal. We realise our hierarchical framework in the context of an effective theory, and we analyse the diphoton signal as well as the consistency with other LHC searches. We finally address the interplay of the LHC results with the dark matter phenomenology, namely the compatibility with the relic density abundance and the indirect detection bounds.

Results on the Spin-Dependent Scattering of Weakly Interacting Massive Particles on Nucleons from the Run 3 Data of the LUX Experiment

We present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4×10^{4}  kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=9.4×10^{-41}  cm^{2} (σ_{p}=2.9×10^{-39}  cm^{2}) at 33  GeV/c^{2}. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Analyzing the Discovery Potential for Light Dark Matter

In this Letter, we determine the present status of sub-GeV thermal dark matter annihilating through standard model mixing, with special emphasis on interactions through the vector portal. Within representative simple models, we carry out a complete and precise calculation of the dark matter abundance and of all available constraints. We also introduce a concise framework for comparing different experimental approaches, and use this comparison to identify important ranges of dark matter mass and couplings to better explore in future experiments. The requirement that dark matter be a thermal relic sets a sharp sensitivity target for terrestrial experiments, and so we highlight complementary experimental approaches that can decisively reach this milestone sensitivity over the entire sub-GeV mass range.

Constraining Dark Matter Interactions with Pseudoscalar and Scalar Mediators Using Collider Searches for Multijets plus Missing Transverse Energy

The monojet search, looking for events involving missing transverse energy (E_{T}) plus one or two jets, is the most prominent collider dark matter search. We show that multijet searches, which look for E_{T} plus two or more jets, are significantly more sensitive than the monojet search for pseudoscalar- and scalar-mediated interactions. We demonstrate this in the context of a simplified model with a pseudoscalar interaction that explains the excess in GeV energy gamma rays observed by the Fermi Large Area Telescope. We show that multijet searches already constrain a pseudoscalar interpretation of the excess in much of the parameter space where the mass of the mediator M_{A} is more than twice the dark matter mass m_{DM}. With the forthcoming run of the Large Hadron Collider at higher energies, the remaining regions of the parameter space where M_{A}>2m_{DM} will be fully explored. Furthermore, we highlight the importance of complementing the monojet final state with multijet final states to maximize the sensitivity of the search for the production of dark matter at colliders.

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.

Search for invisible particles produced in association with single-top-quarks in proton-proton collisions at [Formula: see text] with the ATLAS detector

A search for the production of single-top-quarks in association with missing energy is performed in proton-proton collisions at a centre-of-mass energy of [Formula: see text] with the ATLAS experiment at the large hadron collider using data collected in 2012, corresponding to an integrated luminosity of [Formula: see text] fb[Formula: see text]. In this search, the [Formula: see text] boson from the top quark is required to decay into an electron or a muon and a neutrino. No deviation from the standard model prediction is observed, and upper limits are set on the production cross-section for resonant and non-resonant production of an invisible exotic state in association with a right-handed top quark. In the case of resonant production, for a spin-[Formula: see text] resonance with a mass of [Formula: see text] GeV, an effective coupling strength above [Formula: see text] is excluded at 95[Formula: see text] confidence level for the top quark and an invisible spin-[Formula: see text] state with mass between [Formula: see text] and [Formula: see text] GeV. In the case of non-resonant production, an effective coupling strength above [Formula: see text] is excluded at 95[Formula: see text] confidence level for the top quark and an invisible spin-[Formula: see text] state with mass between [Formula: see text] and [Formula: see text] GeV.