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

Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T

Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above ∼5  GeV/c^{2}, but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85  MeV/c^{2} by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Besides the approach of detecting both scintillation and ionization signals, we exploit an approach that uses ionization signals only, which allows for a lower detection threshold. This analysis significantly enhances the sensitivity of XENON1T to light dark matter previously beyond its reach.

Hadronic and Hadron-Like Physics of Dark Matter

The problems of simple elementary weakly interacting massive particles (WIMPs) appeal to extend the physical basis for nonbaryonic dark matter. Such extension involves more sophisticated dark matter candidates from physics beyond the Standard Model (BSM) of elementary particles. We discuss several models of dark matter, predicting new colored, hyper-colored or techni-colored particles and their accelerator and non-accelerator probes. The nontrivial properties of the proposed dark matter candidates can shed new light on the dark matter physics. They provide interesting solutions for the puzzles of direct and indirect dark matter search.

Results of a Search for Sub-GeV Dark Matter Using 2013 LUX Data

The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering for DM particles with masses of 0.4-5  GeV/c^{2} using 1.4×10^{4}  kg day of search exposure from the 2013 data from the Large Underground Xenon (LUX) experiment for four different classes of mediators. This analysis extends the reach of liquid xenon-based DM search instruments to lower DM masses than has been achieved previously.

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.

Dark Matter Search Results from the PICO-60 C_{3}F_{8} Bubble Chamber

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C_{3}F_{8} located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C_{3}F_{8} exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than one event per month. A blind analysis of an efficiency-corrected 1167-kg day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the weakly interacting massive particle (WIMP)-proton spin-dependent cross section at 3.4×10^{-41}  cm^{2} for a 30-GeV c^{-2} WIMP, more than 1 order of magnitude improvement from previous PICO results.

Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure

We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5  kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σ_{n}=1.6×10^{-41}  cm^{2} (σ_{p}=5×10^{-40}  cm^{2}) at 35  GeV c^{-2}, almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.

Panagiotopoulou E, Panagoulias I, Pandini CE, Panduro Vazquez JG, Pani P, Panitkin S, Pantea D, Paolozzi L, Papadopoulou TD, Papageorgiou K, Paramonov A, Paredes Hernandez D, Parker AJ, Parker MA, Parker KA, Parodi F, Parsons JA, Parzefall U, Pascuzzi VR, Pasner JM, Pasqualucci E, Passaggio S, Pastore F, Pataraia S, Pater JR, Pauly T, Pearson B, Pedraza Lopez S, Pedro R, Peleganchuk SV, Penc O, Peng C, Peng H, Penwell J, Peralva BS, Perego MM, Perepelitsa DV, Perini L, Pernegger H, Perrella S, Peschke R, Peshekhonov VD, Peters K, Peters RFY, Petersen BA, Petersen TC, Petit E, Petridis A, Petridou C, Petroff P, Petrolo E, Petrov M, Petrucci F, Pettersson NE, Peyaud A, Pezoa R, Phillips FH, Phillips PW, Piacquadio G, Pianori E, Picazio A, Piccaro E, Pickering MA, Piegaia R, Pilcher JE, Pilkington AD, Pin AWJ, Pinamonti M, Pinfold JL, Pirumov H, Pitt M, Plazak L, Pleier MA, Pleskot V, Plotnikova E, Pluth D, Podberezko P, Poettgen R, Poggi R, Poggioli L, Pohl D, Polesello G, Poley A, Policicchio A, Polifka R, Polini A, Pollard CS, Polychronakos V, Pommès K, Ponomarenko D, Pontecorvo L, Pope BG, Popeneciu GA, Poppleton A, Pospisil S, Potamianos K, Potrap IN, Potter CJ, Poulard G, Poulsen T, Poveda J, Pozo Astigarraga ME, Pralavorio P, Pranko A, Prell S, Price D, Price LE, Primavera M, Prince S, Proklova N, Prokofiev K, Prokoshin F, Protopopescu S, Proudfoot J, Przybycien M, Puri A, Puzo P, Qian J, Qin G, Qin Y, Quadt A, Queitsch-Maitland M, Quilty D, Raddum S, Radeka V, Radescu V, Radhakrishnan SK, Radloff P, Rados P, Ragusa F, Rahal G, Raine JA, Rajagopalan S, Rangel-Smith C, Rashid T, Raspopov S, Ratti MG, Rauch DM, Rauscher F, Rave S, Ravinovich I, Rawling JH, Raymond M, Read AL, Readioff NP, Reale M, Rebuzzi DM, Redelbach A, Redlinger G, Reece R, Reed RG, Reeves K, Rehnisch L, Reichert J, Reiss A, Rembser C, Ren H, Rescigno M, Resconi S, Resseguie ED, Rettie S, Reynolds E, Rezanova OL, Reznicek P, Rezvani R, Richter R, Richter S, Richter-Was E, Ricken O, Ridel M, Rieck P, Riegel CJ, Rieger J, Rifki O, Rijssenbeek M, Rimoldi A, Rimoldi M, Rinaldi L, Ripellino G, Ristić B, Ritsch E, Riu I, Rizatdinova F, Rizvi E, Rizzi C, Roberts RT, Robertson SH, Robichaud-Veronneau A, Robinson D, Robinson JEM, Robson A, Rocco E, Roda C, Rodina Y, Rodriguez Bosca S, Rodriguez Perez A, Rodriguez Rodriguez D, Roe S, Rogan CS, Røhne O, Roloff J, Romaniouk A, Romano M, Romano Saez SM, Romero Adam E, Rompotis N, Ronzani M, Roos L, Rosati S, Rosbach K, Rose P, Rosien NA, Rossi E, Rossi LP, Rosten JHN, Rosten R, Rotaru M, Roth I, Rothberg J, Rousseau D, Rozanov A, Rozen Y, Ruan X, Rubbo F, Rühr F, Ruiz-Martinez A, Rurikova Z, Rusakovich NA, Russell HL, Rutherfoord JP, Ruthmann N, Ryabov YF, Rybar M, Rybkin G, Ryu S, Ryzhov A, Rzehorz GF, Saavedra AF, Sabato G, Sacerdoti S, Sadrozinski HFW, Sadykov R, Safai Tehrani F, Saha P, Sahinsoy M, Saimpert M, Saito M, Saito T, Sakamoto H, Sakurai Y, Salamanna G, Salazar Loyola JE, Salek D, Sales De Bruin PH, Salihagic D, Salnikov A, Salt J, Salvatore D, Salvatore F, Salvucci A, Salzburger A, Sammel D, Sampsonidis D, Sampsonidou D, Sánchez J, Sanchez Martinez V, Sanchez Pineda A, Sandaker H, Sandbach RL, Sander CO, Sandhoff M, Sandoval C, Sankey DPC, Sannino M, Sansoni A, Santoni C, Santonico R, Santos H, Santoyo Castillo I, Sapronov A, Saraiva JG, Sarrazin B, Sasaki O, Sato K, Sauvan E, Savage G, Savard P, Savic N, Sawyer C, Sawyer L, Saxon J, Sbarra C, Sbrizzi A, Scanlon T, Scannicchio DA, Scarcella M, Scarfone V, Schaarschmidt J, Schacht P, Schachtner BM, Schaefer D, Schaefer L, Schaefer R, Schaeffer J, Schaepe S, Schaetzel S, Schäfer U, Schaffer AC, Schaile D, Schamberger RD, Scharf V, Schegelsky VA, Scheirich D, Schernau M, Schiavi C, Schier S, Schildgen LK, Schillo C, Schioppa M, Schlenker S, Schmidt-Sommerfeld KR, Schmieden K, Schmitt C, Schmitt S, Schmitz S, Schnoor U, Schoeffel L, Schoening A, Schoenrock BD, Schopf E, Schott M, Schouwenberg JFP, Schovancova J, Schramm S, Schuh N, Schulte A, Schultens MJ, Schultz-Coulon HC, Schulz H, Schumacher M, Schumm BA, Schune P, Schwartzman A, Schwarz TA, Schweiger H, Schwemling P, Schwienhorst R, Schwindling J, Sciandra A, Sciolla G, Scuri F, Scutti F, Searcy J, Seema P, Seidel SC, Seiden A, Seixas JM, Sekhniaidze G, Sekhon K, Sekula SJ, Semprini-Cesari N, Senkin S, Serfon C, Serin L, Serkin L, Sessa M, Seuster R, Severini H, Sfiligoj T, Sforza F, Sfyrla A, Shabalina E, Shaikh NW, Shan LY, Shang R, Shank JT, Shapiro M, Shatalov PB, Shaw K, Shaw SM, Shcherbakova A, Shehu CY, Shen Y, Sherafati N, Sherwood P, Shi L, Shimizu S, Shimmin CO, Shimojima M, Shipsey IPJ, Shirabe S, Shiyakova M, Shlomi J, Shmeleva A, Shoaleh Saadi D, Shochet MJ, Shojaii S, Shope DR, Shrestha S, Shulga E, Shupe MA, Sicho P, Sickles AM, Sidebo PE, Sideras Haddad E, Sidiropoulou O, Sidoti A, Siegert F, Sijacki D, Silva J, Silverstein SB, Simak V, Simic L, Simion S, Simioni E, Simmons B, Simon M, Sinervo P, Sinev NB, Sioli M, Siragusa G, Siral I, Sivoklokov SY, Sjölin J, Skinner MB, Skubic P, Slater M, Slavicek T, Slawinska M, Sliwa K, Slovak R, Smakhtin V, Smart BH, Smiesko J, Smirnov N, Smirnov SY, Smirnov Y, Smirnova LN, Smirnova O, Smith JW, Smith MNK, Smith RW, Smizanska M, Smolek K, Snesarev AA, Snyder IM, Snyder S, Sobie R, Socher F, Soffer A, Soh DA, Sokhrannyi G, Solans Sanchez CA, Solar M, Soldatov EY, Soldevila U, Solodkov AA, Soloshenko A, Solovyanov OV, Solovyev V, Sommer P, Son H, Sopczak A, Sosa D, Sotiropoulou CL, Soualah R, Soukharev AM, South D, Sowden BC, Spagnolo S, Spalla M, Spangenberg M, Spanò F, Sperlich D, Spettel F, Spieker TM, Spighi R, Spigo G, Spiller LA, Spousta M, St. 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, 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, 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, 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. Search for dark matter at [Formula: see text] in final states containing an energetic photon and large missing transverse momentum with the ATLAS detector

Results of a search for physics beyond the Standard Model in events containing an energetic photon and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. As the number of events observed in data, corresponding to an integrated luminosity of 36.1 fb[Formula: see text]  of proton-proton collisions at a centre-of-mass energy of [Formula: see text], is in agreement with the Standard Model expectations, model-independent limits are set on the fiducial cross section for the production of events in this final state. Exclusion limits are also placed in models where dark-matter candidates are pair-produced. For dark-matter production via an axial-vector or a vector mediator in the s-channel, this search excludes mediator masses below 750-[Formula: see text] for dark-matter candidate masses below 230-[Formula: see text] at 95% confidence level, depending on the couplings. In an effective theory of dark-matter production, the limits restrict the value of the suppression scale [Formula: see text] to be above [Formula: see text] at 95% confidence level. A limit is also reported on the production of a high-mass scalar resonance by processes beyond the Standard Model, in which the resonance decays to [Formula: see text] and the Z boson subsequently decays into neutrinos.

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.

Results from a Search for Dark Matter in the Complete LUX Exposure

We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×10^{4}  kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50  GeV c^{-2}, WIMP-nucleon spin-independent cross sections above 2.2×10^{-46}  cm^{2} are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1×10^{-46}  cm^{2} at 50  GeV c^{-2}.

Improved Limits on Scattering of Weakly Interacting Massive Particles from Reanalysis of 2013 LUX Data

We present constraints on weakly interacting massive particles (WIMP)-nucleus scattering from the 2013 data of the Large Underground Xenon dark matter experiment, including 1.4×10^{4}  kg day of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength, improved event-reconstruction algorithms, a revised background model including events originating on the detector walls in an enlarged fiducial volume, and new calibrations from decays of an injected tritium β source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4  GeV c^{-2}, these new results give the most stringent direct limits on the spin-independent WIMP-nucleon cross section. The 90% C.L. upper limit has a minimum of 0.6 zb at 33  GeV c^{-2} WIMP mass.