Dark matter research

1. Dark matter research 毕效军

2. 依托国内大科学装置的粒子物理和宇宙学的前沿理论研究依托国内大科学装置的粒子物理和宇宙学的前沿理论研究 1、主要考核指标 提出在西藏羊八井实验、AMS02等实验上进行暗物质探测的具体方案，完成可行性报告，并提出可能的改进方案。进行针对国内外各种最新的实验进行暗物质的理论研究。 三、主要研究内容 I) 现有实验装置上暗物质探测的方案及可行性研究 I.1) 暗物质信号在羊八井实验上观测可能性的研究 II) 未来实验装置探测暗物质的可行性研究 II.1) 暗物质信号在AMS02上观测可能性的研究 II.2) HAWC（High Altitude Water Cherenkov计划） II.3)暗物质粒子探测小卫星项目 III) 暗物质相关理论研究 我们将开展暗物质相关的理论问题研究，紧密结合国际上的大型装置：LHC，PAMELA，AMS02，GLAST，MAGIC，VERITAS，LOFAR，HESS，ICECUBE等 特别是对撞机实验，如正在运行的美国费米实验室的Tevatron和正在建造的欧洲核子中心的大型质子对撞机LHC ，以及正在积极筹划的下一代正负电子直线对撞机ILＣ等…… IV)基于前两年的工作，考虑建造新的大型装置，如地下实验室，新一代大型天文望远镜以及空间卫星项目等，为暗物质研究的科学目标做前期研究。

3. 项目成员 • 成员：毕效军、秦 波、陈大明、刘 纯、杨金民、常 进、胡红波、陈国明、张新民、陈学雷 • 院外合作人员：朱守华、李明哲、赵红胜、王汉国、陶嘉琳

4. Outline • An introduction • Dark matter from astrophysics and cosmology • Dark matter from particle physics • Detection of dark matter (direct, indirect, collider) • Dark matter research in our group

5. Energy budget of the universe

6. Problems with dark matter • Effects on cosmology and astrophysics: large scale structure formation – N-body simulation, reflects the properties of dark matter, cold dark matter, constrain neutrino mass • The nature of dark matter • Related at the small scale

7. Candidates of the cold dark matter • There are dozens of theoretical models in the literature • Weakly Interacting Massive Particles (WIMPs) as thermal relics of Big Bang is a natural candidate of CDM－independently proposed by particle physics. • such as neutralinos, KK states, Mirror particles … The WIMP miracle: for typical gauge couplings and masses of order the electroweak scale, Wwimph2 0.1 (within factor of 10 or so)

8. Thermal history of the WIMP (thermal production) Thermal equilibrium abundance At T >> m, At T < m, At T ~ m/22, ，decoupled, relic density is inversely proportional to the interaction strength For the weak scale interaction and mass scale (non-relativistic dark matter particles) , if and WIMP is a natural dark matter candidate giving correct relic density (proposed trying to solve hierarchy problem).

9. Cosmology/astrophysics/particle physics

10. H. Baer, A. Belyaev, T. Krupovnickas, J. O’Farrill, JCAP 0408:005,2004 • mSUGRA or CMSSM: simplest (and most constrained) model for supersymmetric dark matter • R-parity conservation, radiative electroweak symmetry breaking • Free parameters (set at GUT scale): m0, m1/2, tan b, A0, sign(m) • 4 main regions where neutralino fulfills WMAP relic density: • bulk region (low m0 and m1/2) • stau coannihilation region m  mstau • hyperbolic branch/focus point (m0 >> m1/2) • funnel region (mA,H 2m) • (5th region? h pole region, large mt ?) However, general MSSM model versions give more freedom. At least 3 additional parameters: m, At, Ab (and perhaps several more…)

11. c c _ g p c c e+ n Detection of WIMP • Indirect detection DM increases in Galaxies, annihilation restarts(∝ρ2); ID looks for the annihilation products of WIMPs, such as the neutrinos, gamma rays, positrons at the ground/space-based experiments • Direct detection of WIMP at terrestrial detectors via scattering of WIMP of the detector material. indirect detection collider Direct detection

12. Status of dark matter search • Direct detection (null results)

14. Indirect detection

16. Dark matter from astrophysics • Properties at small scale • Subhalos and central cusp • 511 kev indicates light and scalar particle (next part)

17. Satellite galaxies are seen in Milky Way, e.g. Saggittarius, MCs Predicted number Observed number of luminous satellite galaxies 10km/s 20km/s 100km/s • The predicted number of substructures exceeds the luminous satellite galaxies: dark substructures?

18. CDM Predictions (Mao, Jing, Ostriker, Weller 2004) • <1% of dark matter is in substructures at typical lens positions • Fraction appears too low because most substructures are in the outer parts!

19. 银河系和河外星系相对流强

20. astro-ph/0703308 • The Observed properties of Dark Matter on small spatial scales • Authors: Gerard Gilmore, Mark I. Wilkinson, Rosemary F.G. Wyse, Jan T. Kleyna, Andreas Koch, N. Wyn EvansWe extend the previously known observational relationships and interpret them in terms of a more fundamental pair of intrinsic properties of dark matter itself: dark matter forms cored mass distributions, with a core scale length of greater than about 100pc, and always has a maximum central massdensity with a narrow range. The dark matter in dSph galaxies appears to be clustered such that there is a mean volume mass density within the stellar distribution which has the very low value of about 0.1$\Msun$ pc$^{-3}$ (about 5GeV/c$^2$ cm$^{-3}$). All dSphs have velocity dispersions equivalent to circular velocities at the edge of their light distributions of $\sim 15$km s$^{-1}$. In two dSphs there is evidence that the density profile is shallow (cored) in the inner regions, and so far none of the dSphs display kinematics which require the presence of an inner cusp. The maximum central dark matter density derived is model dependent, but is likely to have a mean value (averaged over a volume of radius 10pc) of $\sim0.1\Msun$ pc$^{-3}$ (about 5GeV/c$^2$ cm$^{-3}$) for our proposed cored dark mass distributions (where it is similar to the mean value), or $\sim60\Msun$ pc$^{-3}$ (about 2TeV/c$^2$ cm$^{-3}$) if the dark matter density distribution is cusped. Galaxies are embedded in dark matter halos with these properties; smaller systems containing dark matter are not observed. How are these observations related with properties of dark matter?

21. Dark matter from particle physics • Quintessino, heavy charged particle, small scale problem • Large flux of positron • Large flux of gamma line • How astro can affect collider phenomena? • LHC on dark matter?

22. Quintessino暗物质唯象 • 由Quintessence的耦合导致的现象：光子偏振面的旋转，自发破缺重子产生 • Quintessino非热产生在星系小尺度结构上的效果 • 对于BBN的影响，7Li的压低 • 存在亚稳定neutralino或stau，特别是带电stau会有许多有趣的现象 • 1) 对撞机实验中会产生稳定的带电重粒子径迹 • 2) 在L3＋C或者IceCube实验中探测到带电重粒子

23. 106 Non-thermal production of quintessino WIMP  quintessino + SM particles (WIMP=weakly interacting massive paricle) SM quintessino WIMP Since the interaction of quintessino is usually suppressed by Planck scale, it is generally called superWIMP. e.g. Gravitino LSP quintessino LKK graviton

24. Quintessino暗物质的性质 Lin, Huang, Zhang, Brandberg 01 What is the central shape of DM profile?

25. 对撞机上产生 • 如果 是NLSP，则所有超对称粒子最终衰变成为 ，将在探测器上见到一条带电径迹 • 将这些 搜集起来，可以用于研究它们的衰变过程，甚至可以在实验室里直接研究引力 • 在LHC/ILC最多可以 产生 Buchmuller et al 2004 Kuno et al., 2004 Feng et al., 2004

26. 探测NLSP • 它们寿命很长，在 秒，几百GeV重，而且带电。 • 高能宇宙线中的中微子打到地球上可以产生超对称粒子，并很快衰变到“亚稳”NLSP粒子。 • L3+C或者IceCube有可能探测到他们。

27. Can you propose a model produce so large positron flux has a characteristic bump? • How to explain?

28. Large flux of gamma ray line • astro-ph/0703512 • Significant Gamma Lines from Inert Higgs Dark Matter • Authors: Michael Gustafsson, Erik Lundstrom, Lars Bergstrom, Joakim EdsjoOne of the most minimal models for dark matter is obtained by adding another Higgs doublet with no direct coupling to fermions. In this so-called Inert Doublet Model it has been shown that the particle playing the role of the usual Higgs may naturally be very heavy, of the order of 500 GeV, without violating electroweak precision bounds. The unbroken discrete symmetry that makes the new scalars inert also means that the lightest is a natural dark matter candidate. For a mass between 40 and 80 GeV, such a particle can give the correct cosmic abundance as measured by WMAP. We show that the loop-induced monochromatic \gamma\gamma and the Z\gamma final states would be exceptionally strong for this dark matter candidate. The energy range and rates for these line processes make them ideal to search for in the upcoming GLAST satellite experiment. Before LHC, GLAST, AMS02, open your mind! Any new models, any new phenomena.

29. The key scientific objectives of the GLAST mission are: To understand the mechanisms of particle acceleration in AGNs, pulsars, and SNRs. Resolve the gamma-ray sky: unidentified sources and diffuse emission. Interstellar emission from the Milky Way and a large number of unidentified sources are prominent features of the gamma-ray sky. Determine the high-energy behavior of gamma-ray bursts and transients. Probe dark matter and early Universe. There are also the possibilities of observing monoenergetic gamma-ray "lines" above 30 GeV from supersymmetric dark matter interaction; detecting decays of relics from the very early Universe, such as cosmic strings or evaporating primordial black holes; or even using gamma-ray bursts to detect quantum gravity effects. The GLAST LAT has a field of view about twice as wide (more than 2.5 steradians), and sensitivity about50 times that of EGRET at 100 MeV and even more at higher energies. It will be able to locate sources to positional accuracies of 30 arc seconds to 5 arc minutes.

30. PAMELA Scientific goals: the understanding of the acceleration and propagation of cosmic rays; the role of solar, terrestrial and heliospheric relationships to energetic particle propagation in the heliosphere. Cosmology in relation to antimatter and dark matter; The PAMELA observations will extend the results of balloon-borne experiments over an unexplored range of energies with unprecedented statistics and complement information gathered from Space Observatories and ground-based cosmic-ray experiments. These observational objectives can be schematically listed in the following points: measurement of the antiproton spectrum up to 190 GeV (present limit 50 GeV); measurement of the positron spectrum up to more than 270 GeV (present limit 30 GeV); search for antinuclei with a sensitivity of some unity in 10-7  in the  antiHe/He ratio (present sensitivity limit about 10-5); measurement of the antiproton spectrum down in energy to less than 80 MeV; measurement of the positron spectrum down in energy to less than 50 MeV;

32. If no SUSY • If susy is correct, how to understand the parmater spcae? • If relic density is too small, other candidate or nonthermal. • If too much dark matter, how to understand? Nonstandard cosmology??

33. Light scalar dark matter • 511 keV line by integral indicates the light (<3 MeV??) and scalar dark matter • What candidate? (Zhu Shou hua) • Detection at BES (Li Hai bo)

34. Attempts at YBJ • Indirect detection from ARGO and HAWC • Indirect detection from AMS • Background study

35. ASg and ARGO： (High Duty cycle,Large F.O.V) ~TeV ~100GeV 中意合作 ARGO实验RPC大厅 中日合作 AS γ实验区闪烁体探测器阵列 Here comes the two experiments hosted by YBJ observatory. One is call ASg, a sampling detector covering 1% of the area and have been operated for 15 years. The other full coverage one is called ARGO, still under installation. ASg use scintillation counter and ARGO use RPC to detector the arrival time and the number of secondary particles, with which the original direction and energy of CR particle can be restored. ASg has a threshold energy at a few TeV while ARGO down to about 100GeV. Both experiment have the advantages in high duty cycle and large field of view. Because for both of the experiments there is only one layer of detector, it is very difficult to separate the g ray shower from CR nucleishowers. Working in the similar energy range on mountain Jemez near Los Alamos, by using water cherenkov technique, MILAGRO has two layer of PMT, which enable it a rather good capability to separate g ray from background. Though it locates in a low altitude, has a smaller effective area, it has similar sensitivity to ASg experiment. To combine this technique with high altitude would greatly improve the sensitivity of our current EAS experiments. ARGO hall, floored by RPC. Half installed.

36. Gamma ray detection from DM annihilation Complementary capabilities ground-based space-based ACTEASPair angular resolution good fair good duty cycle low high high area large large small field of view small large large+ can reorient energy resolution good fair good, with smaller systematic uncertainties

37. 羊八井探测暗物质的几种可能性 • 来自银心的湮灭信号（几乎不能） • 探测来自本征星系群的湮灭信号 • 探测来自银河系暗物质子结构的湮灭信号

39. ASgamma 对于暗物质的限制

40. ARGO constraints from Draco

41. 对本征星系群的观测 • 优势，同时观测许多的源 • 劣势，灵敏度无法和契伦可夫抗衡 • 契伦可夫无法探测未知源和时变源

42. Substructure (subhalo) of the MW Since We can search the annihilation signal from the GC or the subhalos. However, the GC is very complex due to SMBH and other baryonic processes. We investigate the case of subhalos.

43. g-rays from the subhalos Bullock01 g-rays from subhalos source y g-rays from smooth bkg sun GC

44. Constrain SUSY by EAS detectors

45. Sensitivity at ARGO for DM detection（10yr）

46. Sensitivity at HAWC for DM detection（5yr）

47. Detection depends on dark matter model and strongly on the central cusp • What can we do in dark matter detection? • How to cooperate between theoretical and experimental, astrophysics and particle physics studies, members in the project and others?