Mohamad-Ziad Charif - Antares

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600km/s. If we assume the worst case scenario where dark matter is uniformlyrotating in the opposite direction of the Sun, it would still put dark matter relativespeed below the Sun’s escape velocity ensuring that any dark matter particle thatfalls under the Sun’s gravitation well will get trapped. Additionally as we saw earlier,dark matter by interacting with nuclei can lose kinetic energy and get trappedinside heavy celestial objects. The scenario where WIMPs get trapped inside theSun and get by repeated (over a long time) elastic collisions with the nuclei sinkto the core and annihilate, seems to be an extremely plausible scenario.Additionally the Sun is an attractive search place for dark matter for several reasons,the first one is minimal astrophysical uncertainty as searches for dark matterin the galactic center and galactic halo are very sensitive to the form of the halo(cusped or cored). Searching for dark matter in the Sun does not depend on thehalo shape but on the local density which is independent from the halo shape. Thesecond reason is that the astrophysical background for dark matter search in theSun is cosmic-rays hitting the Sun and via p-p interaction creating neutrinos thatwill come from the direction of the Sun. This effect has been studied[74] and theexpected number of events in a detector such as ANTARES is about 10 −3 eventsper year. The final reason is Solar physics that concern us are quite known andhave minimal uncertainties.After WIMPs annihilate, and through different various channels, we will end upwith neutrinos (unless the channel was via photons or electrons). In order to haveinformation on this neutrino flux and its eventual detection in ANTARES, severalprocesses need to be known and calculated, presented as follows:• Number of WIMPs in the Sun as a function of capture rate and annihilation.• Interaction of the resulting particles from annihilation: τ regeneration, hadronizationof quarks, etc.• Neutrino oscillation and interaction from creation point to the detector.Annihilation rate in the SunThe number of WIMPs in the Sun can be described through the following equation[75]:dNdt= C C −C A .N 2 (2.18)The term C C is the WIMPs capture rate by the Sun this factor is mainly determinedby the spin-dependent cross-section of WIMPs on protons. The term C Ais the annihilation term, which is dependent on the annihilation cross-section ofWIMPS. Now if we want to calculate the WIMPs annihilation rate Γ A (eq 2.19 &26
Figure 2.16: Conversion factor from neutrino flux to muon flux as a function ofthe annihilation channel and WIMP mass.2.20)Γ A = 1 2 C AN 2 (2.19)Γ A = 1 2 C C tanh 2 ( t τ ) (2.20)τ =1√CC C A(2.21)We find that if we calculate this rate at our present time (age of the Sun) wheret = t ⊙ ≡ 4.5 · 10 9 years we would get t⊙ τ ≫ 1 ⇒ tanh2 ( t⊙ τ) → 1. This means thatdNdt= 0, and that annihilation and capture are in equilibrium. The consequences ofthis is that once equilibrium is achieved the annihilation rate is dependent on thecapture rate C C . This translates to having the annihilation rare depending solelyon the scattering cross-section.Additionally the two conversion factors that allow us to convert neutrino fluxto muon flux (figure 2.16), and the muon flux to spin-dependent and spin-independent(figure2.17) cross-section were obtained from [75], the calculation was done via the webbasedapplication[76] presented in the same paper.Neutrino productionIf we assume that our WIMPs are neutralino then the annihilation of a pair ofWIMPs can not directly produce neutrinos (but it can if the WIMP is a Kaluza-27
Page 2 and 3: "The most exciting phrase to hear i
Page 4 and 5: 3.2.1.4 Performance and characteris
Page 6 and 7: Chapter 1IntroductionThe early hist
Page 8 and 9: Chapter 2Dark MatterIn this chapter
Page 10 and 11: Figure 2.2: Comparison of the measu
Page 12 and 13: Figure 2.4: CMB anisotropy observed
Page 14 and 15: Figure 2.5: Combination of the WMAP
Page 17: Figure 2.6: Temporal evolution of t
Page 20 and 21: Figure 2.9: Parameter space of m 1/
Page 22 and 23: Figure 2.10: Limits on spin-indepen
Page 26 and 27: Figure 2.14: Detected gamma ray flu
Page 30 and 31: Figure 2.17: Conversion factor from
Page 32 and 33: The eigenstate mixing can be writte
Page 34 and 35: Figure 2.19: Flux of ν µ / ¯ν
Page 36 and 37: Figure 3.1: The neutral current (NC
Page 38 and 39: Muon Energy (GeV )1p| dEdx | (GeV.c
Page 40 and 41: Figure 3.4: Energy loss of per dist
Page 42 and 43: Figure 3.6: Effective muon range as
Page 44 and 45: Figure 3.8: Differential flux of at
Page 46 and 47: 3.2.1.1 Detector layoutOptical Modu
Page 48 and 49: • The LED (light emitting diode)
Page 50 and 51: Anchor & BuoyEach line is anchored
Page 52 and 53: Figure 3.17: Distribution of azimut
Page 54 and 55: Figure 3.20: Height and radial disp
Page 56 and 57: Figure 3.22: Distribution of sea cu
Page 58 and 59: Figure 3.24: Time offset among OMs
Page 60 and 61: Figure 3.26: Distribution of time d
Page 62 and 63: Line number Connection Date Mainten
Page 64 and 65: Figure 3.29: Comparison between sky
Page 66 and 67: Figure 3.31: The effective area for
Page 68 and 69: Figure 4.1: Median counting rate of
Page 70 and 71: Figure 4.4: Average neutrino events
Page 72 and 73: 2. All hits on the same floor are m
Page 74 and 75: 4.2.1 Neutrino simulationFigure 4.6
Page 76 and 77: • Multiplicity range of the muon
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Chapter 5Dark Matter search in the
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Figure 5.2: Annihilation spectrum f
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Livetime(days) 5 Lines 9 Lines 10 L
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Figure 5.4: Monte Carlo Truth distr
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Figure 5.7: Tchi2 distribution for
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Figure 5.9: Tchi2 distribution for
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Figure 5.11: Sun’s position taken
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Figure 5.13: Comparison between the
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Figure 5.15: Estimation of the back
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Figure 5.16: Mean angle between the
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Figure 5.18: A comparison of the di
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a look at figure 5.22 we find a cle
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The resulting optimized sensitiviti
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Figure 5.26: A comparison plot of t
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dΦ µdE ν= dΦ νdE νP earth ρN
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Figure 5.31: Limits on the muon flu
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Chapter 6Dark Matter search in the
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Figure 6.1: . True Position of the
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Figure 6.3: Comparison of the three
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For BBFit all variables mentioned i
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Figure 6.6: The distribution of χ
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annihilation channel W + W − the
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lowering the total contribution of
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6.4.2 BBFit Single-line analysisThe
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Figure 6.15: Comparison between the
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Figure 6.17: Comparison of Nhit dis
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Figure 6.19: The estimation of the
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Figure 6.21: Comparison of the opti
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Figure 6.23: Comparison of sensitiv
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Figure 6.25: Estimation of our back
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Figure 6.28: Comparison of the mult
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Figure 6.29: Comparison of the Λ d
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Figure 6.31: Comparison of the cos(
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Figure 6.34: Comparison of the esti
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The optimal Λ cut for all dark mat
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Figure 6.40: Sensitivity to neutrin
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6.7 Comparison with 2007-2008 analy
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mass of 200 GeV and a cross-section
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Chapter 7ConclusionsThe limits pres
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Bibliography[1] Volders, L. M. J. S
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[22] S. Burles et al., “Big bang
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[46] G. Debrassi, S. Heinemeyer, W.
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[74] C. Hettlage, K. Mannheim, and
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[102] D. Heck and J. Knapp, “Fors
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Mohamad-Ziad Charif - Antares

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