Gustavo Marques-Tavares, Stanford Institute for Theoretical Physics

Detecting dark particles from Supernovae

In collaboration with W. deRocco, P. Graham, D. Kasen and S. Rajendran Dark matter WIMP searches 5

-37 ACKNOWLEDGMENTS 10

-38 10 PandaX-II 2016 10-39 LUX 2016 ) 2 10-40 CDMSLite 2015 CRESST-II 2015 10-41

10-42

-43 10 SuperCDMS Post LHC1 mSUSY constraint 1700 kg-days 10-44

10-45

-46 10 6 t-y PandaX-4T 10-47 XENON1T 2 t-y LZ 15.6 t-y

SI WIMP-nucleon cross section (cm XENONnT 20 t-y 10-48 200 t-y xenon (DARWIN or PandaX-30T) 10-49 Neutrino coherent scattering

10-50 1 10 102 103 WIMP mass (GeV/c2)

*Figure taken from arxiv:1709.00688 This work is supported by grants from the Na- FIG. 4. The projected sensitivity (dashed curves) on the spin- tional Science Foundation of China (Nos. 11435008, independent WIMP-nucleon cross-sections of a selected number of upcoming and planned direct detection experiments, 11455001, 11505112 and 11525522), a grant from the including XENON1T [34], PandaX-4T, XENONnT [34], Ministry of Science and Technology of China (Grant No. LZ [35], DARWIN [36] or PandaX-30T, and SuperCDMS [56]. 2016YFA0400301), and in part by the Chinese Academy Currently leading limits in Fig. 1 (see legend), the neutrino of Sciences Center for Excellence in Particle Physics ‘floor’ [20], and the post-LHC-Run1 minimal-SUSY allowed (CCEPP), the Key Laboratory for Particle Physics, As- contours [21] are overlaid in solid curves for comparison. The trophysics and Cosmology, Ministry of Education, and di↵erent crossings of the experimental sensitivities and the Shanghai Key Laboratory for Particle Physics and Cos- 2 neutrino floor at around a few GeV/c are primarily due to mology (SKLPPC). Finally, we thank the Hong Kong di↵erent threshold assumptions. Hongwen Foundation for financial support.

[1] G. Bertone, D. Hooper, and J. Silk, Phys. Rept. 405, [14] A. Dedes, I. Giomataris, K. Suxho, and J. D. Vergados, 279 (2005), arXiv:hep-ph/0404175 [hep-ph]. Nucl. Phys. B826,148(2010), arXiv:0907.0758 [hep-ph]. [2] C. Savage, K. Freese, and P. Gondolo, Phys. Rev. D74, [15] R. J. Gaitskell, Ann. Rev. Nucl. Part. Sci. 54,315(2004). 043531 (2006), arXiv:astro-ph/0607121 [astro-ph]. [16] R. Bernabei et al., Eur. Phys. J. C73,2648(2013), [3] G. Jungman, M. Kamionkowski, and K. Griest, Phys. arXiv:1308.5109 [astro-ph.GA]. Rept. 267,195(1996), arXiv:hep-ph/9506380 [hep-ph]. [17] C. E. Aalseth et al. (CoGeNT), Phys. Rev. D88,012002 [4] M. C. Smith et al., Mon. Not. Roy. Astron. Soc. 379,755 (2013), arXiv:1208.5737 [astro-ph.CO]. (2007), arXiv:astro-ph/0611671 [astro-ph]. [18] G. Angloher et al., Eur. Phys. J. C72,1971(2012), [5] R. D. Peccei and H. R. Quinn, Phys. Rev. Lett. 38,1440 arXiv:1109.0702 [astro-ph.CO]. (1977). [19] R. Agnese et al. (CDMS), Phys. Rev. Lett. 111,251301 [6] F. Wilczek, Phys. Rev. Lett. 40,279(1978). (2013), arXiv:1304.4279 [hep-ex]. [7] J. E. Kim, Phys. Rept. 150,1(1987). [20] J. Billard, L. Strigari, and E. Figueroa-Feliciano, Phys. [8] D. J. E. Marsh, Phys. Rept. 643,1(2016), Rev. D89,023524(2014), arXiv:1307.5458 [hep-ph]. arXiv:1510.07633 [astro-ph.CO]. [21] E. A. Bagnaschi et al., Eur. Phys. J. C75,500(2015), [9] J. M. Gaskins, Contemp. Phys. 57,496(2016), arXiv:1508.01173 [hep-ph]. arXiv:1604.00014 [astro-ph.HE]. [22] J. Angle et al. (XENON), Phys. Rev. Lett. 100,021303 [10] J. D. Lewin and P. F. Smith, Astropart. Phys. 6,87 (2008), arXiv:0706.0039 [astro-ph]. (1996). [23] E. Aprile et al. (XENON100), Phys. Rev. Lett. 111, [11] L. E. Strigari, New J. Phys. 11,105011(2009), 021301 (2013), arXiv:1301.6620 [astro-ph.CO]. arXiv:0903.3630 [astro-ph.CO]. [24] D. S. Akerib et al. (LUX), Phys. Rev. Lett. 112,091303 [12] A. Gutlein et al., Astropart. Phys. 34,90(2010), (2014), arXiv:1310.8214 [astro-ph.CO]. arXiv:1003.5530 [hep-ph]. [25] D. S. Akerib et al. (LUX), (2015), arXiv:1512.03506 [13] F. Ruppin, J. Billard, E. Figueroa-Feliciano, and L. Stri- [astro-ph.CO]. gari, Phys. Rev. D90,083510(2014), arXiv:1408.3581 [26] A. Tan et al. (PandaX-II), Phys. Rev. Lett. 117,121303 [hep-ph]. (2016), arXiv:1607.07400 [hep-ex]. WIMP searches 5

-37 ACKNOWLEDGMENTS 10

-38 10 PandaX-II 2016 10-39 LUX 2016 ) 2 10-40 CDMSLite 2015 CRESST-II 2015 10-41

10-42

-43 10 SuperCDMS Post LHC1 mSUSY constraint 1700 kg-days 10-44

10-45

-46 10 6 t-y PandaX-4T 10-47 XENON1T 2 t-y LZ 15.6 t-y

SI WIMP-nucleon cross section (cm XENONnT 20 t-y 10-48 200 t-y xenon (DARWIN or PandaX-30T) ? 10-49 Neutrino coherent scattering 10-50 1 10 102 103 WIMP mass (GeV/c2)

3 Low kinetic energy: v 10 ⇠ 6 K 10 m

Large background: Ideas do exist Phys. Rev. D 90, 083510 (2014) how to go beyond this “floor” (directional, annual modulation, etc), but the pragmatic issue is still how to get there Jianglai Liu Pheno 2017 7 Many strategies

‣ Search for electron scattering ‣ Accelerator searches ‣ New targets … Many strategies

‣ Search for electron scattering ‣ Accelerator searches ‣ New targets …

Searching for boosted dark matter from Supernovae Outline

‣ Model ‣ Source: Supernovae ‣ Computing fluxes and projected sensitivity ‣ Conclusion and future directions Dark photon portal

µ µ⌫ A0 ¯ + ✏F 0 F L µ µ⌫

A0 SM ϵ

χ¯ Dark photon portal

µ µ⌫ A0 ¯ + ✏F 0 F L µ µ⌫

A0 SM ϵ

χ¯

mA0 & 200 MeV >m

g e✏ d ¯ J µ L m2 µ EM A0 Dark photon portal g e✏ 4 d µ 2 m ¯ µJ y = ↵ ✏ L m2 EM d m A0 ✓ A0 ◆ ↵y 2 ⇠ m parameter space in these models corresponds to DM-mediator coupling strengths that are SM-like. It is worth noting that the dimensionless variable y is no longer a suitable parameter for presenting results when m >mA0 , as the DM annihilation proceeds trough ¯ A0A0, independent ofDark the kinetic mixing photon strength. However, accelerators portal can still probe interesting! parameter space through o↵-shell DM production and through direct mediator searches, where the mediator decays back to Standard Model Final States. The present status4 and gde✏ µ prospects for visibly-decaying A searches are shown in Fig. 22. These2 searchesm are set to 2 ¯ µJEM 0 y = ↵d✏ continueL testingm the top-down motivated values of ✏ in the near future. m A0 ✓ A0 ◆ Invisibly Decaying Dark Photon A' Missing Mass/Momentum Experiments (Kinetic Mixing, mA'= 3m) -6 10 10-4 2) e + 2 DarkLight DarkLight g- 2) ( g- ( 10-7 10-5 BaBar -8 BaBar 10 10-6 4 PADME

) -9 PADME 10

MMAPS A' 10-7 m MMAPS / 10-10 VEPP-3 NA64 VEPP-3 -8 10 m Fermion 2 NA64 ( 10-11

D Belle II Asymmetric -9 NA64

10 Belle II 2 -12 Target 10 Relic

NA64 = 10-10 -13 Scalar Target y 10 Relic Target LDMX Target Relic -11 -14 Majorana ELDER 10 10 -Dirac LDMX Pseudo 10-12 10-15

-16 10-13 10 1 10 102 103 1 10 102 103

mA' [MeV] m [MeV]

FIG. 18: Current constraints (shaded regions) and sensitivity estimates (dashed lines) on the SM- mediator coupling ✏ = gSM/e, for various experiments based on the missing mass, missing energy and missing momentum approaches.* Figure from The US green Cosmic band Visions show the Report values required to explain the muon (g-2)µ anomaly [53]. Right: Corresponding curves on the parameter y, plotted alongside various thermal relic target. These curves assumes mA0 =3m and ↵D =0.5. For larger mass ratios or smaller values of ↵D, the experimental curves shift downward, but the thermal relic target remains invariant. The asymmetric DM and ELDER targets (see text) are also shown as solid orange and magenta lines, respectively. Courtesy G. Krnjaic.

H. Summary and key points

This chapter has reviewed the science case for an accelerator-based program and outlined a path forward to reach decisive milestones in the paradigm of thermal light DM. The key points of the discussion could be summarized as follows: The scenario in which DM directly annihilates to the SM defines a series of predictive, • well-motivated and bounded targets. Exploring this possibility is an important scientific priority. A new generation of small-scale collider and fixed-target experiments is needed to • robustly test this scenario. The accelerator-based approach has the attractive feature of o↵ering considerable model-independence in its sensitivity to the details of the dark sector, and can uniquely probe all predictive models.

79 parameter space in these models corresponds to DM-mediator coupling strengths that are SM-like. It is worth noting that the dimensionless variable y is no longer a suitable parameter for presenting results when m >mA0 , as the DM annihilation proceeds trough ¯ A0A0, independent ofDark the kinetic mixing photon strength. However, accelerators portal can still probe interesting! parameter space through o↵-shell DM production and through direct mediator searches, where the mediatorg e✏ decays back to Standard Model Final States. The present status4 and d µ 2 m prospects for visibly-decaying2 ¯ µJEMA0 searches are shown in Fig.y = 22.↵d These✏ searches are set to continueL testingm the top-down motivated values of ✏ in the near future. m A0 ✓ A0 ◆ Invisibly Decaying Dark Photon A' Missing Mass/Momentum Experiments (Kinetic Mixing, mA'= 3m) -6 10 10-4 2) e + 2 DarkLight DarkLight g- 2) ( g- ( 10-7 10-5 BaBar -8 BaBar 10 10-6 4 PADME

) -9 PADME 10

MMAPS A' 10-7 m MMAPS / 10-10 VEPP-3 NA64 VEPP-3 -8 10 m Fermion 2 NA64 ( 10-11

D Belle II Asymmetric -9 NA64

10 Belle II 2 -12 Target 10 Relic

NA64 = 10-10 -13 Scalar Target y 10 Relic Target LDMX Target Relic -11 -14 Majorana ELDER 10 10 -Dirac 1 µ LDMX Pseudo ¯ µJ 10-12 10-15 (50 GeV)2 EM -16 10-13 10 1 10 102 103 1 10 102 103

mA' [MeV] m [MeV]

FIG. 18: Current constraints (shaded regions) and sensitivity estimates (dashed lines) on the SM- mediator coupling ✏ = gSM*/e Figure, for various from US experiments Cosmic Visions based onReport the missing mass, missing energy and missing momentum approaches. The green band show the values required to explain the muon (g-2)µ anomaly [53]. Right: Corresponding curves on the parameter y, plotted alongside various thermal relic target. These curves assumes mA0 =3m and ↵D =0.5. For larger mass ratios or smaller values of ↵D, the experimental curves shift downward, but the thermal relic target remains invariant. The asymmetric DM and ELDER targets (see text) are also shown as solid orange and magenta lines, respectively. Courtesy G. Krnjaic.

H. Summary and key points

79 Supernovae Core-Collapse Supernova

‣ Very massive stars, M > 8 Msun, become unstable at the end of their life

‣ Once the iron core reaches the Chandrasekhar limit, M ~ 1.5 Msun, electron degeneracy cannot support the core and it collapses

‣ Densities are so large neutrinos become trapped and the gravitational binding energy is transferred to a large lepton chemical potential Core-Collapse Supernova

Supernova Neutrinos 397

Fig. 11.1. Schematic picture of the core collapse of a massive star ( > M 8 ), of the formation of a neutron-star remnant, and the beginning of∼ a M⊙ SN explosion. There are four main phases numbered 1 4 above the plot: * Figures from: G. Raffelt, “Stars as Laboratories− for Fundamental Physics” , 1996 1. Collapse. 2. Prompt-shock propagation and break-out, release of prompt νe burst. 3. Matter accretion and mantle cooling. 4. Kelvin-Helmholtz cooling of “protoneutron star.” The curves mark the time evolution of several characteristic radii: The stellar iron core (RFe ). The “neutrino sphere” (Rν) with diffusive transport inside, free streaming outside. The “inner core” < (Ric) which for t 0.1 s is the region of subsonic collapse, later it is the settled, compact inner∼ region of the nascent neutron star. The SN shock wave (Rshock) is formed at core bounce, stagnates for several 100 ms, and is revived by neutrino heating—it then propagates outward and ejects the stellar mantle. The shaded area is where most of the neutrino emission comes from; between this area and Rν neutrinos still diffuse, but are no longer efficiently produced. (Adapted from Janka 1993.)

Neutrino trapping has the eﬀect that the lepton number fraction YL is nearly conserved at the value Ye which obtains at the time of trapping. However, electrons and electron neutrinos still interconvert (β equilibrium), causing a degenerate νe sea to build up. The core of a collapsing star is the only known astrophysical site apart from the early universe where neutrinos are in thermal equilibrium. It is the only site where neutrinos occur in a degenerate Fermi sea as the early universe is thought to be essentially CP symmetric with equal numbers of neutrinos and antineutrinos to within one part in 109. When neutrino trapping becomes eﬀective, the lepton fraction per baryon is Y 0.35, L ≈ Core-Collapse Supernova

Supernova Neutrinos 397

‣ Inner region is hot and quasi-static from 1 to 10 seconds

‣ Dark matter flux will be mostly sensitive to what happens at radii < 103 km

the ﬁnal-state electron energy distribution is broad so that one can infer only a lower limit to the ν energy. The measured events at the Kamiokande (Hirata et al. 1987, 1988), IMB (Bionta et al. 1987; Bratton et al. 1988), and BST (Alexeyev et al. 1987, 1988) detectors are summarized in Tabs. 11.1, 11.2, and 11.3. The absolute timing at IMB is accurate to within 50 ms while at SN1987a ± Kamiokande only to within 1 min. At BST, the clock exhibited an erratic behavior which led to± an uncertainty of +2/ 54 s. Within the 400 DetectedChapter neutrinotiming 11 uncertainties signal! the three bursts are contemporaneous− and may

Fig. 11.3. Schematic neutrino “lightcurves” during the phases of (1) core collapse, (2) shock propagationd and shock55 breakout, kpc (3) mantle cooling and accretion, and (4) Kelvin-Helmholtz⇡ cooling. (Adapted from Janka 1993.) its lepton number during the νe burst at shock break-out. This outer part settles within the first* Figures 0.5 1 from: s after G. Raffelt, core bounce, “Stars as emitting LaboratoriesFig. most 11.13. for Fundamental SN 1987A neutrinos Physics” at Kamiokande, , 1996 IMB, and Baksan. The of its energy in the form of neutrinos.− Also, more material is accretedenergies refer to the secondary positrons, not the pimary neutrinos. In the shaded area the trigger efficiency is less than 30%. The detector clocks have while the shock wave stalls. As much as a quarter of the expectedunknown total relative offsets; in each case the first event was shifted to t = 0. In amount of energy in neutrinos is liberated during this phase (No.Kamiokande 3 in and Baksan, the events marked with open circles are usually Figs. 11.1 and 11.3). attributed to background. Meanwhile, the stalled shock wave has managed to resume its outward motion and has begun to eject the overburden of matter. There- fore, the protoneutron star after about 0.5 1 s can be viewed as a star unto itself with a radius of around 30 km− which slowly contracts and cools by the emission of (anti)neutrinos of all flavors, and at the same time deleptonizes by the loss of νe’s. After 5 10 s it has lost most of its lepton number, and slightly later most− of its energy. This is the “Kelvin-Helmholtz cooling phase,” marked as No. 4 in Figs. 11.1 and 11.3. Afterward, the star has become a proper neutron star whose small lepton fraction is determined by the condition of a vanishing neutrino chemical potential (Appendix D.2), and whose further cooling history has been discussed in Sect. 2.3. Immediately after collapse the protoneutron star is relatively cold (see the t = 0 curve in Fig. 11.2). Half or more of the energy to be ra- diated later is actually stored in the degenerate electron Fermi sea with typical Fermi momenta of order 300 MeV. The corresponding degener- Dark matter flux Important effects

Must take into account

‣ Interactions are large, so dark matter is trapped inside Supernova out to larger radii: ‣ Emits as a black-body (surface vs volume) ‣ Lower temperature

‣ Significant velocity spread → signal is significantly spread in time Velocity spread

0.015 m = 10 MeV Tcore = 30 MeV E 60 MeV 0.010 h i⇠

v 0.98 0.005 h i⇠

0.000 0 50 100 150 200 250 300 p (MeV) Velocity spread

0.015 m = 10 MeV Tcore = 30 MeV E 60 MeV 0.010 h i⇠

v 0.98 0.005 h i⇠

0.000 0 50 100 150 200 250 300 55 kpc ~ 180000 light years p (MeV)

‣ Dark matter from SN1987a: still some years to get here

‣ Signal spread: v t 1 dilution v ⇠ ! 180000yr Semi-relativistic DM

‣ Dark matter from SN1987a: still some years to get here

‣ Signal spread: 10-13 dilution

‣ SN1987a not useful ‣ Sensitive to older SN (potentially much closer) ‣ Sensitive to diffuse background of older SN Effects of large interactions?

‣ If interactions are large, dark matter can annihilate fast before getting out of Supernova ‣ It takes time for dark matter to move out since it bounces around scattering with other particles especially if νe has a large mixing angle with the other flavors. A vast number of papers has been devoted to various consequences of flavor oscilla- Understanding Trapped Regime tions on SN neutrinos and their detection (e.g. Raffelt 1996; Lunardini & Smirnov 2001), a topic Useful analogy with neutrino case of serious concern at a time when the phenomenon of flavor oscillations appears to be experimentally established. Moreover, there has been much progress in the numerical treatment of neutrino transport. New algorithms have been developed to effectively solve the Boltzmann collision equation in those critical SN regions where the neutrino mean free path is Fig. 1.— Schematic picture ofInteractions neutrino spectra that change neither long nor short relative to the important ge- Interactions that change formation in the atmosphere ofdirection a SN core. without significant ometric scales (Burrows et al. 2000; Mezzacappaneutrino number and/or energy et al. 2001; Rampp & Janka 2000). With vastly change in energy increased CPU power one is beginning to perform νN Nν,areactionwhichissub-dominant simulations where a reliable transport scheme is for the↔ electron flavor. The nucleon mass m = self-consistently coupled with the hydrodynamic 938 MeVFigure is much taken from: larger G. Raffelt than astro-ph/0105250 the relevant temper- evolution so that the calculated multi-flavor neu- atures which are around T =10MeVsothaten- trino fluxes and spectra will depend only on the ergy exchange between neutrinos and nucleons is adopted input physics. inefficient. However, nucleon-nucleon bremsstrah- Our present approach is complementary to lung NN NNνν¯ as well as the leptonic pro- ↔ these global numerical simulations. We study νµ cesses e+e− νν¯ and νe eν allow for the ex- ↔ ↔ and ντ transport and spectra formation in the change of energy and the creation or destruction framework of the simplest possible model that of neutrino pairs and thus keep neutrinos in local incorporates enough of the essential physics to thermal equilibrium up to a radius where these re- mimic the full problem. This approach allows us actions freeze out, the “energy sphere.” However, to ascertain the significance (or irrelevance) of mi- the neutrinos are still trapped by νN Nν up to croscopic input-physics variations that may mod- the “transport sphere” whence they stream↔ freely. ify the spectra. The nontrivial insights gathered Between the energy and transport spheres, neutri- from this study can serve as a basis for a more in- nos propagate by diffusion. This region plays the formed choice about the micro-physics that should role of a scattering atmosphere. be implemented in a full simulation. In addition, In all numerical simulations of SN neutrino our approach has the pedagogical benefit of pro- transport the neutrino collisions in the scatter- viding a simple and transparent framework for ing atmosphere were treated as iso-energetic so understanding the crucial physics. that the energy ϵ2 of the outgoing neutrino in The spectra formation problem is schematically νN Nν was set equal to the energy ϵ1 of the illustrated in Fig. 1. The electron (anti-)neutrinos initial→ state. The main motivation for this approx- are kept in thermal equilibrium by beta processes imation was its numerical simplicity and the lack up to a radius usually referred to as the “neutrino of a compelling interest in details of the emerg- sphere.” Beyond this radius the neutrinos stream ing νµ and ντ spectra. It is clear, however, that off freely, their spectrum representing the medium iso-energetic collisions are not a particularly good temperature at the neutrino sphere. Of course, approximation. In Fig. 2 we show the distribution this picture is crude because the interaction cross of final-state energies ϵ2 when ϵ1 =30MeVand 2 section varies as ϵ (neutrino energy ϵ)sothat the medium temperature is 10 MeV. A typical different energy groups decouple at different radii nucleon velocity is then about 20% of the speed and thus at different medium temperatures. of light so that it is not surprising that even after The other flavors interact with the medium pri- asinglecollisiontheneutrinoenergyisconsider- marily by neutral-current collisions on nucleons ably smeared out. Since neutrinos interact many

2 Understanding Trapped Regime

‣ Ultimately described by a Boltzmann equation ‣ Reasonable results can be obtained using a “freeze-out” calculation. Understanding Trapped Regime

‣ Ultimately described by a Boltzmann equation ‣ Reasonable results can be obtained using a “freeze-out” calculation.

Freeze-out Freeze-out in time in space

Rate ~ 1/timescale

e.g. H n v ⇠ h i Understanding Trapped Regime

‣ Ultimately described by a Boltzmann equation ‣ Reasonable results can be obtained using a “freeze-out” calculation.

Freeze-out Freeze-out in time in space

Rate ~ 1/timescale Mean free path ~ typical distance

e.g. e.g. 1 H n v r ⇠ h i n(r) ⇠ h i Freeze-out Picture

‣ RN : Number sphere

RE + ¯ e e !

‣ RE : Energy sphere R N e± e± !

‣ RT : Transport sphere R T p p ! Radial freeze-out

Freeze-out requirement:

No other interactions Diffusion

{ { ann ann

It takes ann longer to cover T ann ⇣ ⌘ Radial freeze-out

Freeze-out requirement:

1 dr 1 dr ⌧x = =2/3 ⌧ann = =2/3 p Zrx x ZrN ann T

T ⌧ ann Annihilations become effectively more efficient Freeze-out calculation

1 dr Annihilation Sphere: ⌧ann = =2/3 p ZrN ann T

rN Treat as a perfect black-body

2 2 1 1 (E m) rN = dE | 4⇡2 eE/T(rN ) +1 Zm Flux transmission

Flux decreases due to scattering with protons Flux transmission

2 (rN ) rN (r rN )= (1 + 3 s ) r 4 ⇤ ⇣ ⌘

2 1 rN s = T dr np(r) ⇤ r r Z N ⇣ ⌘ Flux transmission

2 (rN ) rN (r rN )= (1 + 3 s ) r 4 ⇤ ⇣ ⌘

2 1 rN s = T dr np(r) ⇤ r r Z N ⇣ ⌘

Currently we treat the effect of the energy sphere by assuming it doesn’t change the total flux but redistributes momenta according to the temperature in rE Computing the ﬂux

Snapshot at 1.5 seconds post bounce

1000 40 ] 3 ) cm

/ 10 30 g 11 MeV ( 10 T [ 20 0.100 ρ 10

0.001 0 0 20 40 60 80 100 0 20 40 60 80 100 r (km) r (km) What is the ﬂux on Earth?

‣ Single Supernova near Earth

‣ Diffuse signal from past Supernovae in the galaxy

‣ Diffuse signal from extra galactic Supernovae Diffuse background

‣ Estimated galactic rate is around 2 Supernovae per century (maybe higher in the past) ‣ Assuming constant rate across the galactic disk we can translate the diffuse flux in terms of an equivalent single event

2 RSN t di↵ =0.0381 sn(RSN) kpc 50years ✓ ◆ Detecting DM ﬂux

‣ Electron targets: k m v e ⇡ e DM me e / E Detecting DM ﬂux

‣ Electron targets: k m v e ⇡ e DM me e / E

‣ Nuclear targets

k 2p n ⇡ Z2 n / Detecting DM ﬂux

‣ Electron targets: k m v e ⇡ e DM me e / E

‣ Nuclear targets 2 2p kn 2p Er ⇡ ⇡ mn 2 n Z / pXe 17 MeV min ⇡ Cooling bounds

‣ We have observed the neutrinos from SN1987a with spectrum consistent with predictions ‣ A conservative criteria for when new particles lead to such large deviations that the expected neutrino signal would be significantly changed is:

L 3 1052ergs/s & ⇥ Preliminary reach plot Galactic diffuse Supernovae flux

-6 BaBar

-8 E137 -10 Relic Density LSND )

y -12 ( log -14 BBN DARWIN (200 ton-yrs) LZ (15 ton-yr) Cooling -16 thresh=5 keV Δt=log(10) s -18 diffuse galactic bg

101 102 mass (MeV) Preliminary reach plot Galactic diffuse Supernovae flux

-6 BaBar

-8 E137 -10 Relic Density LSND )

y -12 ( DARWIN (200 ton-yrs) log -14 BBN LZ (15 ton-yr) 1 ton-yr Cooling -16 thresh=2.5 keV Δt=log(10) s -18 diffuse galactic bg

101 102 mass (MeV) Conclusions ‣ Supernovae can be a source of boosted dark sector particles. Because of their large velocity, they are more easily detected than the local dark matter population. ‣ Some regions of parameter space might be probed by Xenon1T and a large region will be tested in future Xe experiments. ‣ Fluxes could be larger depending on time-scales associated with the Supernova. ‣ Need to explore profile dependence. ‣ We explored a minimal heavy dark photon portal scenario. This analysis can be extended to a number of other dark sector scenarios. ‣ These models might also lead to interesting new features in Supernovae that haven’t been explored…