Pos(ICRC2017)891 Puebla, for Dark ﬁeld-Of-View † Signiﬁcant Excess Lifetime Limits

Home , Triangulum II

PoS(ICRC2017)891 Puebla, for dark http://pos.sissa.it/ field-of-view † significant excess lifetime limits. performed an indirect search for the HAWC Collaboration ICRC2017 b ∗ from dark matter annihilation and decay considering vari- for dark matter annihilation and decay at dark matter masses spheroidal galaxies (dSphs), the M31 galaxy and the Virgo cluster, 4100m. The HAWC observatory and Andrew J. Smith a [email protected] [email protected] above1TeV. We will present the annihilation cross-section and decay as well asacombined limit using the dSphs. HAWC has not seen statistically from these sources. We searched matter via GeV-TeV photons resulting ous sources, includingf dwar Mexico at an altitude of observatory sensitive to 0.5 TeV - 100 TeV gamma-rays and cosmic-rays in the State of The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide Speaker. Complete list of authors at http://www.hawc-observatory.org/collaboration/icrc2017.php † ∗ Copyright owned by the author(s) under the terms of the Creative Commons University of Rochester University of Maryland, College Park c Bexco, Busan, Korea 10–20 July, 2017 35th International Cosmic Ray — Conference E-mail: E-mail: Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). Dark Matter Searches with HAWC Tolga Yapici, a b PoS(ICRC2017)891 59.7’ N and ◦ ]. WIMP-like Andrew J. Smith 3 , 2 ] and the trigger rate 9 ), in this analysis, we treated them as point ◦ 3-6 ∼ 1 ]. 7 , 6 , ]. A total of 15 dSphs are considered in this analysis: Bootes I, Canes 5 8 , ] energies. HAWC consists of 300 water Cherenkov detectors (WCDs) 4 9 ]. WIMPs can annihilate into standard model particles and produce photons. area. Each detector contains four photo-multiplier tubes [ 1 2 18.6’ W. HAWC is a survey instrument that is sensitive to gamma rays of 500 GeV ◦ 2 sr. ∼ It has been operating with a partial detector since August 2013 and has been operating with The High Altitude Water Cherenkov (HAWC) observatory detects high-energy gamma-ray and The best DM decay lifetime limits are expected to come from the most massive objects in the Among the places in the Universe to look for signatures of dark matter, dwarf spheroidal galax- Despite the fact that dark matter should exist in the universe, it composition is still in question. covering 22000 m of HAWC is approximately 25kHz.view HAWC of has a duty cycle >95% and a wide, unbiased fieldthe of full detector since Marchthe 2015. full detector. Here we present results from 507 days of its operations with is located at Sierra Negra, Mexico. The site is 4100 m above sea level, at latitude 18 universe such as galaxies andEven galaxy though clusters, these thus sources we are studied extended sources M31 ( galaxy and the Virgo Cluster. 2. HAWC Observatory to a few hundred TeV [ particles which decay may beby responsible the for IceCube the detector [ observation of an astrophysical neutrino excess Venatici I, Canes Venatici II,Sextans, Coma Berenices, Ursa Draco, Major Hercules, I, Leofor Ursa their I, Major favored Leo declination II, angle II, Ursa for Leo thewith Minor IV, HAWC respect and observatory Segue to and TriangulumII. 1, other well These dSphs. studied dark dSphs matter were content chosen sources. More detailedshould analyses provide better incorporating limits their than presented DM here. morphology are in progress and they longitude 97 ies (dSphs) are some ofcontent the and best low candidates luminous for material. acompanion dark The galaxies matter dwarf of search spheroidal the due galaxies Milky to consideredluminosity Way, their in galaxies, in high this with what dark analysis low is diffuse matter are known Galacticcal as gamma-ray gamma-ray our production foregrounds Local [ and Group. little to They no are astrophysi- very low WIMPs can also have large darkquantity matter and decay lifetimes energy and to would the produce observed gamma rays neutrinos, in from similar 100 TeV to several PeV [ Among the possible darkone matter of candidates, the leading Weakly hypothetical Interacting particlematter Massive physics candidates particle Particles for that (WIMPs) cold interacts are dark matter. withto A known the WIMP standard weak is force a model dark [ particles via a force similar in strength Dark Matter Searches with HAWC 1. Introduction PoS(ICRC2017)891 ) r ) is and J (3.6) (3.5) (3.4) (3.1) (3.2) (3.3) is the x β , s r -factor ( ] for different J is the gamma- << Andrew J. Smith 11 r dE / γ dN α / is the slope for , ) . γ γ 2 − x )) )) β . J ( x x γ ) , , E N α ) + D θ θ d ) d ( γ ( θ s r E ( r 2 i N χ ( instead of the square: d gal s v / d 2 r r M ρ A ρ ( cos ρ χ π σ x ρ is the dark matter particle mass. h 8 M + ( d ) of a spherical system varies with distance ( xR is the angle between the center of the source and 1 χ dx 1 2 ρ 2 = Z ( πτ θ M γ 4 Z − ) Ω s 2 d Ω r = R d : / r q ( 3.1 source decay annihilation Z source ) = E F ) = Z E F x ) squared and integrated along the line of sight distance = d r d d d , ( ρ = J θ ( D is the scale radius of the galaxy, r NFW s r ρ is the transition parameter from inner slope to outer slope. NFW profiles α ] are used for all sources listed, except for Triangulum II, for dSphs. The J- 10 and s r is the velocity-weighted dark matter annihilation cross-section, i >> v r is the scale density, A s σ ρ h Density profiles describe how the density ( Decay process involves only one particle, thus, the gamma-ray flux from dark matter decay Expected gamma-ray fluxes from dark matter annihilation were calculated using both the as- The gamma-ray flux from dark matter decay is similar to the dark matter annihilation gamma- is the distance to the center of the source, and from its center. We usedfiles. the Navarro-Frenk-White The (NFW) NFW density model profile for is the given dark by matter density pro- where 3.2 Dark Matter Density Distributions slope for parameters from [ and D-factor for 14 dSph sources are calculated using the CLUMPY software [ depends on a single power of the dark matter density trophysical properties of the potentialand dark final-state matter particles source for andThe the different differential particle dark gamma-ray properties matter flux of integrated masses over the and solid initial angle for of different the source annihilation is channels. given by: ray flux as described above in Equation Dark Matter Searches with HAWC 3. Dark Matter Gamma-ray Flux 3.1 Gamma-ray Flux from Dark Matter Annihilation and Decay where over the solid angle of the observation region: where the distance from the earth to a point within the source is given by R the line of sight. ray spectrum per dark matterdefined annihilation, and as the dark mass density ( PoS(ICRC2017)891 . D max max θ ), the θ and for near J Dec ◦ sr) 5 − ]. The mean 13 Andrew J. Smith and 0.2 ]. For M31 and the ◦ 14 ] are used for all dSphs ), declination ( 10 (D/GeVcm RA 10 factors from [ D sr) log 5 − and cm J ] and the Virgo Cluster [ 2 . For Triangulum II, we use the 12 1 ] are used, respectively. J-factors and D-factors are (J/GeV 13 3 10 ] and [ 12 for respective sources. max ]. The overall systematic uncertainty on the HAWC data set is on θ 9 -factor are listed above. NFW profiles parameters from [ D ]. 50% on the observed flux. The uncertainties on the expected dark matter annihilation 14 LeoI 152.11 12.29 17.57 18.04 M31 10.68 41.27 20.86 19.10 LeoII 168.34 22.13 18.11 17.33 Draco 260.05 57.07 19.37 19.15 LeoIV 173.21 -0.53 16.37 16.50 ± -factor and Source RA Dec log Segue1 151.75 16.06 19.66 18.64 ComaB 186.74 23.90 19.32 18.71 Sextans 153.28 -1.59 17.96 18.59 Bootes1 210.05 14.49 18.47 18.45 J Hercules 247.72 12.75 16.93 16.87 UrsaMinor 227.24 67.24 19.24 17.92 UrsaMajorI 158.72 51.94 18.66 18.11 UrsaMajorII 132.77 63.11 19.67 19.05 ]. A similar procedure was applied for M31 [ Astrophysical parameters, J-factors and D-factors, for the fifteen dwarf spheroidal galaxies within TriangulumII 33.32 36.18 20.44 18.42 Virgo Cluster 186.75 12.38 19.50 19.44 CanesVenaticiI 202.04 33.57 17.62 17.55 CanesVenaticiII 194.29 34.32 17.95 17.68 10 Systematic uncertainties arise from a number of sources within the detector. These effects There are additional systematic uncertainties on the expected dark matter flux due to the in- zenith angles. In themakes case J- of and D-factors better smaller. angulargle Similarly, resolutions, for gets the worse greater integration angular that resolutions angle makes cases, thedark gets the matter J- smaller distribution integration and which which an- D- limits factors the largerWe dark values. impose matter content However, this there of physically is a motivated constraint source at on constraint angles the on larger than the J- and D- factor uncertainties. For com- realizations of the tabulated values and their respective uncertainties for an angular window of listed, except for Triangulum II. For Triangulum II, we use the calculated for integration angle of from [ factors from [ 3.3 Systematics were carefully investigated in [ tegration angle of J- and D-factor. HAWC has an angular resolution between 1 the order of and decay limits were calculated to account for these systematics uncertainties. Table 1: the HAWC field-of-view, M31 and Virgodark Cluster. matter The source, right ascension ( Virgo Cluster, the profile parameters from [ values of the J- and D-factors are tabulated in Table Dark Matter Searches with HAWC PoS(ICRC2017)891 100.0 . 2 ], HESS HESSHESS Magic Segue1Magic Segue1 Fermi CombinedFermi Combined 18 and 1 Andrew J. Smith ] V e T [

10.0 VirgoVirgo Thermal DMThermal DM Veritas Segue1Veritas Segue1 M (b) + Preliminary ], Veritas Segue 1 limits [ ], the limits were calculated assum- 9 HAWC (w/ TriII)HAWC (w/ TriII) HAWC (w/o TriII)HAWC (w/o TriII) M31M31 17 channel. The rest of the results can be ¯ annihilation channels and (b) its comparison τ τ − 1.0 2 4 6 8 ] are shown along with the HAWC M31 and 2 2 2 2 τ

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1 3 τ 4 0.5 degrees) [ ∼ 100.0 + -factor and transits near the zenith for HAWC. How- J , for the individual sources. A joint likelihood analysis τ CanesVenaticiIICanesVenaticiII SextansSextans UrsaMajorIUrsaMajorI UrsaMajorIIUrsaMajorII UrsaMinorUrsaMinor ] and it still has large uncertainties in its DM proﬁle. Because 16 ] V e T [

10.0 LeoILeoI LeoIILeoII LeoIVLeoIV HerculesHercules Bootes1Bootes1 CanesVenaticiICanesVenaticiI M ] and MAGIC Segue 1 limits [ (a) 19 and decay lifetime i v A σ Preliminary h ] with the explanation of the limit calculations. For other possible studies, ﬂux upper HAWC (w/ TriII)HAWC (w/ TriII) HAWC (w/o TriII)HAWC (w/o TriII) TriangulumIITriangulumII Segue1Segue1 DracoDraco ComaBComaB 15 95% conﬁdence level upper limits on the dark matter annihilation cross-section (a) for 15 dwarf 1.0 8 4 6 8 0 2 2 2 2 1 2 2 Triangulum II has a particularly large We analyzed the individual and combined limits from 15 dwarf spheroidal galaxies within the

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1 3 limits were also presented in the respective paper. ing that the dSphs arefor point a sources. range of No darkSo, statistically matter we significant calculated masses, gamma-ray 95% 1 confidence flux level TeV hasthe limits – on been source 100 the found significance TeV, annihilation and cross-section is five and usedcross-section decay dark to lifetime, matter determine annihilation the channels. exclusionwas curves also on completed the by combining dark the matterof statistics the annihilation for analysis. all In 15 this dSphs paper, in we order only to present increase results the for sensitivity ever, it was discovered recently [ of this, we show the joint dwarf limit both with and without Triangulum II in Figures Figure 1: spheroidal galaxies within the HAWC field of view for the combined dSph limits [ HAWC field of view, M31 galaxy andthe the angular Virgo Cluster resolution for of the HAWC observatory HAWC 507 ( days data. Considering found in [ 4. Limits on the Dark Matter Annihilation Cross Section and Decay Lifetime with to other experimental results, Fermi-LAT combined dSph limitsVirgo [ Cluster limits. The gray bandsystematics shows and the dark systematic orange uncertainty band on shows the the combined systematic limits uncertainty due due to to HAWC J-factor uncertainty. bined limit uncertainties, we used thecross-section uncertainties limits corresponding and to 38% Segue1 for (42% decay for lifetime annihilation limits) since it is one of the dominant sources. Dark Matter Searches with HAWC PoS(ICRC2017)891 2 0 1 ) I I ) ) ) i I I I I r I ) I ) i i I i I T r I I r r

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C C C C C C C C C C W W W W W W W W W W at the source channel. The A A A A A A A A A A H H H H H H H H H H 2 − Andrew J. Smith ρ τ R + ] V τ e 1 T 0 [

1 M 4 TeV, the followed by (b) 4 TeV, and HAWC limit ∼ + ) ∼ + + o ) W ) g o o r i g g b r r V ) i b W ) i (

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s s s s C C C C C a a a a t t t t i i i i W W W W W r r r r A A A A A e e e e H H H H H V V V V 0 annihilation channel is considered for the 0 1 8 7 6 5 4 3 2 1 0 2 2 2 2 2 2 2 2 2 −

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1 1 1 1 1 1 1 1 1 ] s [ W + 10 TeV, the HAWC combined dSph limit is the 5 2 W ∼ 0 1 (total dark matter mass) compared to + ρ R CanesVenaticiIICanesVenaticiII SextansSextans UrsaMajorIUrsaMajorI UrsaMajorIIUrsaMajorII UrsaMinorUrsaMinor channels, the HAWC combined dSph limits are the strongest . The gray band shows the systematic uncertainty on the combined − − τ τ 30 TeV. This result is consistent within uncertainties with Veritas + + τ 10 TeV. Beyond & τ ∼ χ ] V e 1 M T 0 and [

1 LeoILeoI LeoIILeoII LeoIVLeoIV HerculesHercules Bootes1Bootes1 CanesVenaticiICanesVenaticiI M − ] for the (a) 20 TeV. Slower dark matter velocity enhances the amplitude of resonances, µ 21 + ∼ µ channel, Fermi-LAT limit is the most contraining up to channel for Preliminary shows 15 individual dSph, the combined, M31 and the Virgo cluster limits. Like ¯ b − b 2 HAWC (w/o TriII)HAWC (w/o TriII) HAWC (w/ TriII)HAWC (w/ TriII) TriangulumIITriangulumII Segue1Segue1 DracoDraco ComaBComaB W 95% conﬁdence level lower limits on the dark matter decay lifetime (a) for 15 dwarf spheroidal + W 0 0 1 0 4 3 2 1 8 7 6 5 Dark matter models for thermal relic and Sommerfeld enhanced cross-sections are compared. For the Figure 2 2 2 2 2 2 2 2 2

0 0 0 0 0 0 0 0 0 ]. At resonances, HAWC limit rules out a dark matter with mass of

1 1 1 1 1 1 1 1 1 ] s [ 22 of annihilation or decay. The strongestVirgo lifetime Cluster lower limit results is are obtained with withingood the 2–3 limits factors for annihilation, of the the goodDM combined decay mass dSph lifetime in limits the limits. for cluster. the Despite Virgo not Cluster providing is due to the total Figure 2: galaxies within the HAWC field ofVeritas view Segue and 1 (b) limits for combined, [ M31 and Virgo Cluster limits compared with limits due to HAWC systematicsuncertainty. and dark orange band shows the systematic uncertainty due to D-factor For the Sommerfeld enhancement,matter a velocity weak-scale of 300 coupling km/s was of assumed. 1/35 Only and a very conservative dark the dark matter annihilation results,though Segue for 1, decays, Bootes Coma I Berenices,fact and that and dark Draco Triangulum matter also II decay contribute are is to related dominant, to the combined limits. This is due to the Segue 1 limit. For most stringent limit for this channel.for The the HAWC combined limits with Triangulum II are strongest Dark Matter Searches with HAWC MAGIC Segue 1 limit up to above a few TeV. M31whereas limits the are Virgo Cluster also is comparable not as with sensitive the as M31 combined galaxy limits (Figure with Triangulum II approaches to corresponding Sommerfeld-enhancedmatter models with by mass 1 of orderthus of making magnitude HAWC results for closer to a Sommerfeld-enhanced dark thermal relic. Sommerfeld enhancement since this channel is assured to[ have dark matter coupled to gauge bosons PoS(ICRC2017)891 ]. ]. , 267 JHEP . , ]. 1701.01778 Andrew J. Smith 1510.00389 Observation of the Decaying ,[ CLUMPY: Jeans (Mar, 2015) 74 ]. Physics Reports , ]. 1506.07628 801 ,[ (Jan., 2017) , [ ]. 1507.01000 First observation of PeV-energy (May, 2016) 103009 1304.5356 ,[ ,[ 93 Dwarf galaxy annihilation and decay ArXiv e-prints , New limits on the dark matter lifetime from (Mar, 2016) 336–349 1311.5238 (2015) 055 ,[ 6 Supersymmetric dark matter The Astrophysical Journal 200 , ]. Phys. Rev. D . 1512 (2013) 021103 , Evidence for High-Energy Extraterrestrial Neutrinos at the 111 ]. JCAP , Boosted Dark Matter in IceCube and at the Galactic Center (2013) 1242856 ]. 1311.5864 collaboration, M. Aartsen et al., Are IceCube neutrinos unveiling PeV-scale decaying dark matter? Geometric Compatibility of IceCube TeV-PeV Neutrino Excess and its , 342 1308.1105 ]. Phys.Rev.Lett. hep-ph/9506380 , ,[ 15 ,[ Science , 1503.02669 ,[ OLLABORATION (2013) 054 C collaboration, M. Aartsen et al., Computer Physics Communications , 1311 UBE UBE C C (2015) 105 CE CE dwarf spheroidal galaxies using Fermi-LAT emission profiles for dark matter experiments analysis neutrinos with IceCube IceCube Detector JCAP (Mar., 1996) 195–373 04 Galactic Dark Matter Origin Crab Nebula with the HAWC Gamma-Ray Observatory Leptophilic Dark Matter at IceCube We acknowledge the support from: the US National Science Foundation (NSF); the US Department of En- The HAWC collaboration is improving its analysis tools for enhancing energy and angular We present 95% CL limits on the annihilation cross section and the decay lifetime for 15 [8] M. G. Baring, T. Ghosh, F. S. Queiroz and K. Sinha, [2] J. Kopp, J. Liu and X.-P. Wang, [4]I [5]I [6] A. Esmaili and P. D. Serpico, [7] Y. Bai, R. Lu and J. Salvado, [9] A. U. Abeysekara, A. Albert, R. Alfaro, C. Alvarez, J. D. Álvarez, R. Arceo et al., [3] S. M. Boucenna, M. Chianese, G. Mangano, G. Miele, S. Morisi, O. Pisanti et al., [1] G. Jungman, M. Kamionkowski and K. Griest, [10] A. Geringer-Sameth, S. M. Koushiappas and M. Walker, [11] V. Bonnivard, M. Hütten, E. Nezri, A. Charbonnier, C. Combet and D. Maurin, ergy Office of High-EnergyAlamos Physics; National Laboratory; the Consejo Nacional Laboratory de55155, Ciencia Directed y 105666, Research Tecnología 122331, (CONACyT), Mexico and 132197, (grants 167281, 260378, DevelopmentIG100414-3, 167733); 232656, (LDRD) IN108713, Red IN121309, program de IN115409, Física IN111315); of de VIEP-BUAPconsin (grant Los Altas 161-EXC-2011); Alumni Energías, the Mexico; University Research DGAPA-UNAM of (grants Foundation; Wis- National the Laboratory; the Institute Luc of Binette Foundation Geophysics, UNAM Postdoctoral Planetary Fellowship Physics, program. and Signatures atReferences Los Alamos resolution. In addition, with more datadark matter collected, masses. HAWC is expected to be more sensitive at lower Acknowledgments dwarf spheroidal galaxies within thecombined HAWC field-of-view, limit M31 is Galaxy also and shown thethe from limits Virgo a Cluster. also stacked shown A analysis in [ of all dwarf spheroidal galaxies. These are Dark Matter Searches with HAWC 5. Summary PoS(ICRC2017)891 , , , , Phys. Rev. D Dark Matter , (Apr., 2015) A New Faint Andrew J. Smith ArXiv e-prints Limits to dark , 802 Mon. Not. Roy. Dark Matter Dark matter , (Feb, 2016) 039–039 Dark matter VERITAS deep 2016 (Mar, 2012) 062001 85 . Monthly Notices of the Royal , Astrophys. J. Lett. Stellar mass map and dark matter , ]. Survey π Phys. Rev. D , ]. (oct, 2012) A4 ]. . 546 7 1603.08046 ,[ Sommerfeld enhancements for thermal relic dark matter ]. . 1005.4678 1410.2589 ,[ ,[ The flattening of the concentration-mass relation towards low ]. (Feb, 2014) (Aug, 2014) 2271–2277 1703.04937 Journal of Cosmology and Astroparticle Physics 89 ,[ , 442 ]. Astronomy & Astrophysics , (Sept., 2016) 2914–2928 (Dec, 2014) 112012 (Oct., 2010) 083525 ]. 1706.01277 ]. 90 82 461 Phys. Rev. D , 1503.05554 ,[ (Apr., 2017) 082001 1202.2144 1601.06590 [ observations of the dwarf spheroidal galaxy[ Segue 1 Search for dark matter annihilation signatures in H.E.S.S. observations of dwarf spheroidal galaxies Phys. Rev. D halo masses and its implications for the annihilation signal boost annihilation and decay from non-spherical dark halos in galactic dwarf satellites L18 Constraints from Observations of 25 MilkyTelescope Way Satellite Galaxies with the Fermi Large Area Phys. Rev. D matter annihilation cross-section from a combineddwarf analysis satellite of galaxies MAGIC and Fermi-LAT observations of distribution in M31 Astronomical Society Astron. Soc. 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