Dark Sector Science in 2019
Philip Schuster (SLAC)
Jefferson Lab Seminar January 30, 2019 Outline
This talk is intended as a primer on the motivation for dark sectors (and dark photons) and to explain the important contributions of Jefferson Lab experiments to this science in 2019
• Dark matter, dark sectors, and the broadening of the US dark matter search program
• Dark photons in the MeV-GeV mass range
• Dedicated dark photon experiments at Jefferson Lab in 2019 (APEX & HPS)
• The future
2 Dark Matter
Halo (Dark Matter) Disk Bulge CMB Power Spectrum Lensing Rotation curves
We know there is new physics in the form of dark matter!
But what is it?
3 Dark Matter Hints
• Old – dark matter imprint in Cosmic Microwave Background ➝ made during or before big bang • Cold – dark matter must have been non-relativistic to form small cosmological structures • Can’t have strong- or electromagnetic- strength interactions with familiar matter (even weak interactions are significantly constrained by data)
This leaves a lot of room for speculation…
4 A Strong Candidate: WIMP DM
Simple, familiar particle content gW gSM
weak force new matter
DM with thermal freeze-out origin Simple, predictive cosmology
Motivated mass range
MeV GeV TeV
WIMP Moving Beyond WIMPs Developing simple ideas beyond the WIMP hypothesis — in response to powerful limits from LHC and direct detection experiments — has arguably been one of the most important developments in particle phenomenology over the last 10 years!
Dark Sector Candidates, Anomalies, and Search Techniques
zeV aeV feV peV neV µeV meV eV keV MeV GeV TeV PeV 30M ≈
QCD Axion WIMPs
Ultralight Dark Ma5er Hidden Sector Dark Ma5er Black Holes
Pre-InflaIonary Axion Hidden Thermal Relics / WIMPless DM
Post-InflaIonary Axion Asymmetric DM
Freeze-In DM
SIMPs / ELDERS
Beryllium-8 US Cosmic Visions: New Ideas in Dark Matter 2017 Muon g-2 arXiv:1707.04591 [hep-ph] Small-Scale Structure
Small Experiments: Coherent Field Searches, Direct DetecIon, Nuclear and Atomic Physics, Accelerators Microlensing ≈
zeV aeV feV peV neV µeV meV eV keV MeV GeV TeV PeV 30M 6
FIG. 1: Mass ranges for dark matter and mediator particle candidates, experimental anomalies, and search techniques described in this document. All mass ranges are merely representative; for details, see the text. The QCD axion mass upper bound is set by supernova constraints, and may be significantly raised by astrophysical uncertainties. Axion-like dark matter may also have lower masses than depicted. Ultralight Dark Matter and Hidden Sector Dark Matter are broad frameworks. Mass ranges corresponding to various production mechanisms within each framework are shown and are discussed in Sec. II. The Beryllium-8, muon (g 2), and small-scale structure anomalies are described in VII. The search techniques of Coherent Field Searches, Direct Detection, and Accelerators are described in Secs. V, IV, and VI, respectively, and Nuclear and Atomic Physics and Microlensing searches are described in Sec. VII.
II. SCIENCE CASE FOR A PROGRAM OF SMALL EXPERIMENTS
Given the wide range of possible dark matter candidates, it is useful to focus the search for dark matter by putting it in the context of what is known about our cosmological history and the interactions of the Standard Model, by posing questions like: What is the (particle physics) origin of the dark matter particles’ mass? What is the (cosmological) origin of the abundance of dark matter seen today? How do dark matter particles interact, both with one another and with the constituents of familiar matter? And what other observable consequences might we expect from this physics, in addition to the existence of dark matter? Might existing observations or theoretical puzzles be closely tied to the physics of dark matter? These questions have many possible answers — indeed, this is one reason why
13 Moving Beyond WIMPs Developing simple ideas beyond the WIMP hypothesis — in response to powerful limits from LHC and direct detection experiments — has arguably been one of the most important developments in particle phenomenology over the last 10 years! Dark Sector Candidates, Anomalies, and Search Techniques
zeV aeV feV peV neV µeV meV eV keV MeV GeV TeV PeV 30M ≈
QCD Axion WIMPs
Ultralight Dark Ma5er Hidden Sector Dark Ma5er Black Holes
Pre-InflaIonary Axion Hidden Thermal Relics / WIMPless DM
Post-InflaIonary Axion Asymmetric DM
Freeze-In DM
SIMPs / ELDERS
Beryllium-8 Thermal Relics US Cosmic Visions: New Ideas in Dark Matter 2017 Muon g-2 arXiv:1707.04591 [hep-ph] Small-Scale Structure
Small Experiments: Coherent Field Searches, Direct DetecIon, Nuclear and Atomic Physics, Accelerators Microlensing ≈
zeV aeV feV peV neV µeV meV eV keV MeV GeV TeV PeV 30M 7
FIG. 1: Mass ranges for dark matter and mediator particle candidates, experimental anomalies, and search techniques described in this document. All mass ranges are merely representative; for details, see the text. The QCD axion mass upper bound is set by supernova constraints, and may be significantly raised by astrophysical uncertainties. Axion-like dark matter may also have lower masses than depicted. Ultralight Dark Matter and Hidden Sector Dark Matter are broad frameworks. Mass ranges corresponding to various production mechanisms within each framework are shown and are discussed in Sec. II. The Beryllium-8, muon (g 2), and small-scale structure anomalies are described in VII. The search techniques of Coherent Field Searches, Direct Detection, and Accelerators are described in Secs. V, IV, and VI, respectively, and Nuclear and Atomic Physics and Microlensing searches are described in Sec. VII.
II. SCIENCE CASE FOR A PROGRAM OF SMALL EXPERIMENTS
Given the wide range of possible dark matter candidates, it is useful to focus the search for dark matter by putting it in the context of what is known about our cosmological history and the interactions of the Standard Model, by posing questions like: What is the (particle physics) origin of the dark matter particles’ mass? What is the (cosmological) origin of the abundance of dark matter seen today? How do dark matter particles interact, both with one another and with the constituents of familiar matter? And what other observable consequences might we expect from this physics, in addition to the existence of dark matter? Might existing observations or theoretical puzzles be closely tied to the physics of dark matter? These questions have many possible answers — indeed, this is one reason why
13 Lessons From Data
Direct detection and LHC experiments have very good sensitivity to DM interacting through W/Z/h bosons!
The ingredients most at odds with data underlying WIMPs is that they are heavy (~GeV and up) and their interactions are mediated by the W/Z bosons Lessons From History
Known ~5% of Universe is rather interesting. If history is any guide, expect the next ~25% to have surprises in store for us! Lessons From History
Known ~5% of Universe is rather interesting. If history is any guide, expect the next ~25% to have surprises in store for us!
Elementary Dark Matter? Dark Matter matter content? Force Carriers?
?… ?… DM A’
?… ?… ?… ?…
?… ?… ?… ?…
?… ?… ?… ?… Lessons From History
Simple, familiar particle content gW gSM
weak force new matter Lessons From History
Simple, familiar particle content gD gSM
new force? new matter
So, what if dark matter (like all other known matter) is charged under its own forces? New Forces Interacting with The Standard Model
Simple, familiar particle content gD gSM
new force new matter Standard Model symmetries allow two types of (dim. 4) interactions with new force carriers at low-energy 1 Y µ Vector Mixing 2 Y Fµ F 0
Higgs Mixing h 2 ⇥ 2 h | | | |
+ a few other closely related possibilities…(see 1707.04591) New Forces Interacting with The Standard Model
Simple, familiar particle content gD gSM
new force new matter Standard Model symmetries allow two interactions with new force carriers at low-energy Most compatible with cosmology & simple dark 1 Y µ matter models, and Vector Mixing 2 Y Fµ F 0 illustrates much of the essential physics Higgs Mixing h 2 ⇥ 2 h | | | | focus of this talk
Increasingly constrained by LHC (though other scalar couplings less constrained) Hidden Sector Dark Matter & Dark Photons
Simple, familiar particle content gD gSM
new force new matter
Dark Matter charged under a new force
“Dark Photons” are the simplest realization of this broad idea (captures much of the essential phenomenology!) A Strong Candidate: Hidden Sector DM (interacting through dark photon)
Simple, familiar particle content gD gSM
new force new matter
Provides a familiar and simple explanation for dark matter stability (i.e. lightest charged particle is stable!) A Strong Candidate: Hidden Sector DM (interacting through dark photon)
Simple, familiar particle content gD gSM
new force new matter
DM with thermal freeze-out origin Simple, predictive cosmology A Strong Candidate: Hidden Sector DM (interacting through dark photon)
Simple, familiar particle content gD gSM
new force new matter
DM with thermal freeze-out origin Simple, predictive cosmology
Motivated (broader) mass range
MeV GeV TeV
Thermal DM WIMP
Dark/Hidden sector Planning Next Steps
Significant planning efforts under way in 2016-2018 to define and launch a new (small-scale) program of dark matter studies to capture the broader landscape of well-motivated possibilities
Dark Sectors 2016 Workshop: Community Report US Cosmic Visions: New Ideas in Dark Matter 2017 : Community Report Jim Alexander (VDP Convener),1 Marco Battaglieri (DMA Convener),2 Bertrand 3 4, Echenard (RDS Convener), Rouven Essig (Organizer), ⇤ Matthew Graham Marco Battaglieri (SAC co-chair),1 Alberto Belloni (Coordinator),2 Aaron Chou (WG2 5, 6 5, (Organizer), † Eder Izaguirre (DMA Convener), John Jaros (Organizer), ‡ Gordan 3 4 5 7 8 Convener), Priscilla Cushman (Coordinator), Bertrand Echenard (WG3 Convener), Krnjaic (DMA Convener), Jeremy Mardon (DD Convener), David Morrissey (RDS 6 3 9 5, 1 Rouven Essig (WG1 Convener), Juan Estrada (WG1 Convener), Jonathan L. Feng Convener), Tim Nelson (Organizer), § Maxim Perelstein (VDP Convener), Matt Pyle 7 3 3 10 11 5, 6, (WG4 Convener), Brenna Flaugher (Coordinator), Patrick J. Fox (WG4 Convener), (DD Convener), Adam Ritz (DMA Convener), Philip Schuster (Organizer), ¶ Brian 8 2 5 5, 6, Peter Graham (WG2 Convener), Carter Hall (Coordinator), Roni Harnik (SAC Shuve (RDS Convener), Natalia Toro (Organizer), ⇤⇤ Richard G Van De Water (DMA 3 9, 8 10 12 5, 13 3 14 15 member), JoAnne Hewett (Coordinator), Joseph Incandela (Coordinator), Eder Convener), Daniel Akerib, Haipeng An, Konrad Aniol, Isaac J. Arnquist, David 11 12 15 15 16 17 18 Izaguirre (WG3 Convener), Daniel McKinsey (WG1 Convener), Matthew Pyle (SAC M. Asner, Henning O. Back, Keith Baker, Nathan Baltzell, Dipanwita Banerjee, 12 13 14 Brian Batell,19 Daniel Bauer,7 James Beacham,20 Jay Benesch,17 James Bjorken,5 Nikita member), Natalie Roe (Coordinator), Gray Rybka (SAC member), Pierre Sikivie 15 7 9, 16 Blinov,5 Celine Boehm,21 Mariangela Bond´ı,22 Walter Bonivento,23 Fabio Bossi,24 (SAC member), Tim M.P. Tait (SAC member), Natalia Toro (SAC co-chair), 17 18 Stanley J. Brodsky,5 Ran Budnik,25 Stephen Bueltmann,26 Masroor H. Bukhari,27 Richard Van De Water (SAC member), Neal Weiner (SAC member), Kathryn 13, 12 14 19 20 Raymond Bunker,15 Massimo Carpinelli,28, 29 Concetta Cartaro,5 David Cassel,1, 5 Gianluca Zurek (SAC member), Eric Adelberger, Andrei Afanasev, Derbin Alexander, 21 22 23 24 Cavoto,30 Andrea Celentano,2 Animesh Chaterjee,31 Saptarshi Chaudhuri,8 Gabriele James Alexander, Vasile Cristian Antochi, David Mark Asner, Howard Baer, 25 26 27 28 Chiodini,24 Hsiao-Mei Sherry Cho,5 Eric D. Church,15 D. A. Cooke,18 Jodi Cooley,32 Dipanwita Banerjee, Elisabetta Baracchini, Phillip Barbeau, Joshua Barrow, 33 34 18 35 29 arXiv:1707.0459130 31 9 32 Robert Cooper, Ross Corliss, Paolo Crivelli, Francesca Curciarello, Annalisa Noemie Bastidon, James Battat, Stephen Benson, Asher Berlin, Mark Bird, Nikita D’Angelo,36, 37 Hooman Davoudiasl,38 Marzio De Napoli,22 Ra↵aella De Vita,2 Achim Blinov,9 Kimberly K. Boddy,33 Mariangela Bond`ı,34 Walter M. Bonivento,35 Mark Denig,39 Patrick deNiverville,11 Abhay Deshpande,40 Ranjan Dharmapalan,41 Bogdan Boulay,36 James Boyce,37, 31 Maxime Brodeur,38 Leah Broussard,39 Ranny Budnik,40 Philip Dobrescu,7 Sergey Donskov,42 Raphael Dupre,43 Juan Estrada,7 Stuart Fegan,39 Torben Bunting,12 Marc Ca↵ee,41 Sabato Stefano Caiazza,42 Sheldon Campbell,7 Tongtong Cao,43 Ferber,44 Clive Field,5 Enectali Figueroa-Feliciano,45 Alessandra Filippi,46 Bartosz Gianpaolo Carosi,44 Massimo Carpinelli,45, 46 Gianluca Cavoto,22 Andrea Celentano,1 Jae Fornal,47 Arne Freyberger,17 Alexander Friedland,5 Iftach Galon,47 Susan Gardner,48, 47 Hyeok Chang,6 Swapan Chattopadhyay,3, 47 Alvaro Chavarria,48 Chien-Yi Chen,49, 16 Francois-Xavier Girod,17 Sergei Gninenko,49 Andrey Golutvin,50 Stefania Gori,51 Christoph • DarkKenneth Sectors Clark,50 John Clarke, 122016Owen Colegrove, 10reportJonathon Coleman, 51—David Cooke,25 Grab,18 Enrico Graziani,52 Keith Gri oen,53 Andrew Haas,54 Keisuke Harigaya,10, 55 Robert Cooper,52 Michael Crisler,23, 3 Paolo Crivelli,25 Francesco D’Eramo,53, 54 Domenico Christopher Hearty,44 Scott Hertel,10, 55 JoAnne Hewett,5 Andrew Hime,15 David Hitlin,3 D’Urso,45, 46 Eric Dahl,29 William Dawson,44 Marzio De Napoli,34 Ra↵aella De Vita,1 10, 55, 1 41 56 15 Yonit Hochberg, Roy J. Holt, Maurik Holtrop, Eric W. Hoppe, Todd W. EstablishPatrick DeNiverville, the55 Stephen community Derenzo,13 Antonia Di Crescenzo, 56,and 57 Emanuele Di 15 7 34 57 58 5 Hossbach, Lauren Hsu, Phil Ilten, Joe Incandela, Gianluca Inguglia, Kent Irwin, Marco,58 Keith R. Dienes,59, 2 Milind Diwan,11 Dongwi Handiipondola Dongwi,43 Alex 59 60 61 62 12 Igal Jaegle, Robert P. Johnson, Yonatan Kahn, Grzegorz Kalicy, Zhong-Bo Kang, Drlica-Wagner,3 Sebastian Ellis,60 Anthony Chigbo Ezeribe,61, 62 Glennys Farrar,18 4 63 49 17 Vardan Khachatryan, Venelin Kozhuharov, N. V. Krasnikov, Valery Kubarovsky, scopeFrancesc of Ferrer, science63 Enectali Figueroa-Feliciano,64 Alessandra Filippi,65 Giuliana Fiorillo,66 1 5, 8 13, 8 35 5 Eric Kuflik, Noah Kurinsky, Ranjan Laha, Gaia Lanfranchi, Dale Li, Tongyan 67 31 40 68 10, 55 61 12 12 15 64 Bartosz Fornal, Arne Freyberger, Claudia Frugiuele, Cristian Galbiati, Iftah Lin, Mariangela Lisanti, Kun Liu, Ming Liu, Ben Loer, Dinesh Loomba, 7 69 70 71 9 65, 66, 67 68 69 Galon, Susan Gardner, Andrew Geraci, Gilles Gerbier, Mathew Graham, Edda Valery E. Lyubovitskij, Aaron Manalaysay, Giuseppe Mandaglio, Jeremiah 72 73, 74 75 76 arXiv:1608.08632v1 [hep-ph] 30 Aug 2016 • 2017Gschwendtner, US CosmicChristopher Hearty, VisionsJaret Heise, Reyco Henning, reportRichard J. — 70 38 5 2 5 Mans, W. J. Marciano, Thomas Markiewicz, Luca Marsicano, Takashi Maruyama, 16, 3 5 21, 77 8 78 49 71 72 10 arXiv:1707.04591v1 [hep-ph] 14 Jul 2017 Hill, David Hitlin, Yonit Hochberg, Jason Hogan, Maurik Holtrop, Ziqing Victor A. Matveev, David McKeen, Bryan McKinnon, Dan McKinsey, Harald 29 23 79 80 8, 9 9 39 68 5 5 73 Hong, Todd Hossbach, T. B. Humensky, Philip Ilten, Kent Irwin, John Jaros, Merkel, Jeremy Mock, Maria Elena Monzani, Omar Moreno, Corina Nantais, 53 41 68 81 Sebouh Paul,53 Michael Peskin,5 Vladimir Poliakov,74 Antonio D Polosa,75, 76 Maxim SharpenRobert Johnson, theMatthew science Jones, Yonatan Kahn, caseNarbe Kalantarians, andManoj 7 14 13, 12 43, 31 Pospelov,6, 11 Igor Rachek,77 Balint Radics,18 Mauro Raggi,30 Nunzio Randazzo,22 Blair Kaplinghat, Rakshya Khatiwada, Simon Knapen, Michael Kohl, Chris 82 83 3 31 21, 77 Ratcli↵,5 Alessandro Rizzo,36, 37 Thomas Rizzo,5 Alan Robinson,7 Andre Rubbia,18 David Kouvaris, Jonathan Kozaczuk, Gordan Krnjaic, Valery Kubarovsky, Eric Kuflik, arXiv:1608.08632 84, 85 41 86 12, 13 Rubin,1 Dylan Rueter,8 Tarek Saab,78 Elena Santopinto,2 Richard Schnee,79 Jessie ideasAlexander for Kusenko, newRafael experiments Lang, Kyle Leach, Tongyan Lin, Mariangela 68 87 17 17 88 3 17 Shelton,80 Gabriele Simi,81, 82 Ani Simonyan,43 Valeria Sipala,28, 29 Oren Slone,83 Elton Lisanti, Jing Liu, Kun Liu, Ming Liu, Dinesh Loomba, Joseph Lykken, Katherine 89 4 90 9 1 Smith,17 Daniel Snowden-I↵t,84 Matthew Solt,5 Peter Sorensen,10, 55 Yotam Soreq,34 Mack, Jeremiah Mans, Humphrey Maris, Thomas Markiewicz, Luca Marsicano, C. Stefania Spagnolo,24, 85 James Spencer,5 Stepan Stepanyan,17 Jan Strube,15 Michael J. Marto↵,91 Giovanni Mazzitelli,26 Christopher McCabe,92 Samuel D. McDermott,6 Art Sullivan,5 Arun S. Tadepalli,86 Tim Tait,47 Mauro Taiuti,2, 87 Philip Tanedo,88 Rex McDonald,71 Bryan McKinnon,93 Dongming Mei,87 Tom Melia,13, 85 Gerald A. Miller,14 Kentaro Miuchi,94 Sahara Mohammed Prem Nazeer,43 Omar Moreno,9 Vasiliy Morozov,31 Frederic Mouton,61 Holger Mueller,12 Alexander Murphy,95 Russell Neilson,96 Tim Basic Research Needs study for Dark-Matter Small Projects
Shaped by formal DOE oHEP charge:
• Identify priority science opportunities and high impact parameter space targets
• Identify high impact opportunities which can be pursued by small projects
• Suggest opportunities that could be pursued by future small projects
HEPAP Brochure — https://science.energy.gov/~/media/hep/hepap/pdf/201811/BRN_Dark-Matter-Brochure_HEPAP_201811.pdf Rocky Kolb’s November 2018 HEPAP talk — https://science.energy.gov/~/media/hep/hepap/pdf/201811/RKolb-HEPAP_201811.pdf 18 An Emerging Program
Rocky Kolb’s November 2018 HEPAP talk — https://science.energy.gov/~/media/hep/hepap/pdf/201811/RKolb-HEPAP_201811.pdf 19 An Emerging Program
HEPAP Brochure 20 — https://science.energy.gov/~/media/hep/hepap/pdf/201811/BRN_Dark-Matter-Brochure_HEPAP_201811.pdf An Emerging Program
HEPAP Brochure 21 — https://science.energy.gov/~/media/hep/hepap/pdf/201811/BRN_Dark-Matter-Brochure_HEPAP_201811.pdf An Emerging Program
All three PRD’s are extremely interesting, but in the interest of time I will focus on PRD#1, as this relates directly to ongoing Jefferson Lab efforts.
HEPAP Brochure 22 — https://science.energy.gov/~/media/hep/hepap/pdf/201811/BRN_Dark-Matter-Brochure_HEPAP_201811.pdf An Emerging Program
Rocky Kolb’s November 2018 HEPAP talk 23 — https://science.energy.gov/~/media/hep/hepap/pdf/201811/RKolb-HEPAP_201811.pdf Future Goals (in my own words!)
Key goals for accelerator experiments:
• Produce and detect sub-GeV dark matter directly
• Produce and detect sub-GeV mediator particles directly
• Test coupling-mass combinations directly relevant to thermal origin dark matter, in additional to broad exploration
For sub-GeV dark matter and dark forces, achieving these goals requires experiments with low to moderate energy beams over a range of beam intensities 24 Future Goals (in my own words!)
Key goals for accelerator experiments: Significant • Produce and detect sub-GeV dark matter directly Jefferson Lab contributions! • Produce and detect sub-GeV mediator particles directly
• Test coupling-mass combinations directly relevant to thermal origin dark matter, in additional to broad exploration
For sub-GeV dark matter and dark forces, achieving these goals requires experiments with low to moderate energy beams over a range of beam intensities 25 Physics of Dark Photons Nicest (common) example is vector-photon kinetic mixing 1 Y µ 2 Y Fµ F 0 Vector mixing effectively gives matter of electric charge qe a vector A′ coupling ∝ qεe ⇒ Wherever there are photons (and sufficient phase space), there are “dark” photons
+ Annihilation:e A′
e γ Decay: Radiation:e 0 A′ A′ 26 Organizing the Physics (Vector kinetic mixing as an example — most models work similarly)
DM and Mediator Production
Contact operator
heavy DM production A′ (off-shell A’)
¯ Resonant DM DM = 2 m production Aʹ (on-shell A’) m 2 me Visibly decaying mediator;
Dark photon mass photon Dark Near-threshold DM production (off-shell mediator) 0 Dark matter mass e+ Search for both the mediator A′ and DM itself! e 27 Organizing the Physics (Vector kinetic mixing as an example — most models work similarly)
DM and Mediator Production
Contact operator
heavy DM production A′ (off-shell A’)
¯ Resonant DM DM = 2 m production Aʹ (on-shell A’) m 2 me Visibly decaying mediator;
Dark photon mass photon Dark Near-threshold DM production (off-shell mediator) 0 Dark matter mass e+
Search for both the mediator A′ JLab experiments! and DM itself! e 28 Visible “Dark Photons”
e+ 10-4 A′ KLOE -5 HADES KLOE BaBar e 10 a ,5 APEX PHENIX Test A1 a ,±2 favored -6 NA48/2 10 a Natural parameter space E774 e is illustrated by coupling 10-7
2 on y-axis, mediator mass -8 10 E141 on x-axis.
10-9
10-10 Orsay U70 10-11 10-3 10-2 10-1 1
mA' [GeV] 29 Visible “Dark Photons”
e+ 10-4 A′ KLOE -5 HADES KLOE BaBar e 10 a ,5 APEX PHENIX Test Red/green: e, A1 a ,±2 favored -6 NA48/2 anomalous dipole 10 ae E774 10µm moments prompt 10-7 2 -8 10 E141 displaced 1mm All other colors: Pair
10-9 resonance searches
10-10 10cm Orsay U70 Gray: Beam Dump 10-11 10-3 10-2 10-1 1
mA' [GeV] 30 Visible “Dark Photons”
e+ 10-4 A′ KLOE -5 HADES KLOE BaBar e 10 a ,5 APEX PHENIX Test A1 a ,±2 favored -6 NA48/2 10 a E774 e
10-7 Recent accelerator 2 -8 experiments have 10 E141 tested interpretation 10-9 of muon g-2 anomaly from dark 10-10 Orsay U70 photon –– if it 10-11 decays visibly! 10-3 10-2 10-1 1
mA' [GeV] 31 Visible “Dark Photons”
10-4 KLOE -5 HADES KLOE BaBar 10 a ,5 APEX PHENIX Test A1 a ,±2 favored -6 NA48/2 10 a E774 e
10-7 2 -8 10 E141 Jesse Thaler: APS 2017
-9 10 Hints from 10-10 Orsay U70 measured 10-11 10-3 10-2 10-1 1 structure for DM mA' [GeV] self-interactions 32 Visible “Dark Photons”
e+ 10-4 A′ KLOE -5 HADES KLOE BaBar e 10 a ,5 APEX PHENIX Test A1 a ,±2 favored -6 NA48/2 10 a E774 e Mixing in Grand 10-7 Unified Theories 2 -8 10 E141 A0 X γ 10-9
10-10 Orsay Tree-level and one-loop U70 -11 forbidden. 10 -3 -2 -1 10 10 10 1 2-loop mixing is expected! mA' [GeV] 33 Visible “Dark Photons”
e+ 10-4 A′ KLOE -5 HADES KLOE BaBar e 10 a ,5 APEX PHENIX Test A1 a ,±2 favored -6 NA48/2 10 a E774 e Mixing in Grand 10-7 Unified Theories 2 -8 10 E141 sub-GeV mass scale 10-9 compatible with 10-10 Orsay epsilon magnitude U70 10-11 coupling to SM Higgs 10-3 10-2 10-1 1
mA' [GeV] 34 Visible “Dark Photons”
10-4 10-4 mA' =1.3 mDM , aD =0.5 Early universe thermal freeze- 10-5 KLOE out cross-section bounded by -5 HADES KLOE BaBar DM abundance 10 a ,5 APEX PHENIX Test -6 A1 10 a ,±2 favored -6 NA48/2 ¯ e+ 10 a E774 e Aʹ 10-7 10-7 2 e 2
-8 Bound 10 -8 e 10 E141 Relic 2 Scalar m Bound 2 -9 10 -9 Inelastic Relic ⇤v D⇥ 10 Bound 4 and ⇠ ⇥ m Relic A0 Fermion Elastic 10-10-10 Fermion 10 Majorana OrsayDirac - U70 For part of DM-A’ mass range,
-11 Pseudo provides a lower limit on 1010-11 3 2 2 1 3 110- 1010 - 1010- 110 mediator coupling vs mass! A' Mass MeV mA' [GeV]
H L 35 Near Future Opportunities!
US Cosmic Visions: New Ideas in Dark Matter 2017 arXiv:1707.04591-4 [hep-ph] 10 Incredible progress expected KLOE KLOE with next round of small-scale -5 KLOEHADES BaBar 10 aμ,5σ APEX PHENIX Test experiments A1 aμ,±2 σ favored -6 NA48/2 10 E774 a e HPS * GUT-level coupling PADME DarkLight APEX * well-motivated mass range 10-7 * thermal dark matter region VEPP-3 Belle-II
2 Mu3e LHCb -1 ϵ MMAPS 5ab of interest -8 10 E141 * (not discussed) Be8,
HPS EDGES… 10-9
LHCb 10-10 Program is multi-purpose — Orsay/E137/CHARM/U70 Pre-2021 will uniquely test many -11 models beyond kinetic mixing 10 -3 -2 -1 10 10 10 1 and beyond vector mediators! mA' [GeV] 36 Dark Sectors at JLab: 2019
Two Jefferson Lab experiments that address dark matter/dark sector physics goals have upcoming runs in 2019!
APEX — “A Prime EXperiment" in Hall A (February-March run!)
HPS — “Heavy Photon Search” in Hall B (June-August run!)
I’ll describe the approach common to these experiments first
37 Dark Sectors at JLab: 2019
Signal process occurs via A’-emission off beam electron scattering on high-Z target
Kinematically irreducible backgrounds originate from “trident” reactions
38 Dark Sectors at JLab: 2019
Signal and background peaked at opposite ends of phase space! 39 APEX @ JLab: 2019
. Experimental Setup
Electron, P = E0/2 Spectrometers
Septum Septum e– HRS−left HRS detectors
Beam
TargetW target e+ HRS−right
Positron, P = E0/2
. Approach: Detect narrow (signal) resonance in electron-positron pairs above smooth trident background near the energy endpoint
Symmetric kinematics well matched to maximizing signal to background 40 APEX @ JLab: 2019
. Experimental Setup Good mass resolution requires Electron, P = E0/2 minimal scattering in target!
Septum Septum e– HRS−left HRS detectors
Beam
TargetW target e+ HRS−right
Positron, P = E0/2
.
Project led by Silviu Covrig and team! 41 APEX @ JLab: 2019
. Experimental Setup
Electron, P = E0/2
Septum Septum e– HRS−left HRS detectors Beam Measuring 100’s of MeV mass range requires forward kinematics TargetW target e+ HRS−right At same time, want relatively high
Positron, P = E0/2 energy electron-positron energy
. (compared to beam) to avoid potential hadronic backgrounds
Project led by collaborators at Carnegie Mellon, NCCU, Cal State LA, Perimeter, Stony Brook, UVA, Rutgers, Hebrew University 42 APEX @ JLab: 2019
. Experimental Setup
Electron, P = E0/2
Septum Septum e– HRS−left HRS detectors
Beam
TargetW target e+ HRS−right
Positron, P = E0/2
“SciFi” .
Recent efforts led by U. of Glasgow, Andrew Moyer, Toshiyuki Gogami, and many others over past several years! 43 APEX @ JLab: 2019
. Experimental Setup
Electron, P = E0/2
Septum Septum e– HRS−left HRS detectors
Beam
TargetW target e+ HRS−right
Positron, P = E0/2
.
Many thanks to recent efforts from Florian Hauenstein, Alexandre Camsonne, Bob Michaels, Evan McClellan and other tritium collaborators 44 APEX @ JLab: 2019
Test run (2010): concept & technical 2019 Physics Run (2/7 - 3/13): start with a demonstration; weekend run achieved single 2.2 GeV run configuration to deliver first world-record sensitivity, highly cited PRL physics results at high statistics. Focus on mass range below muon threshold to complement CERN LHCb efforts 10-4 Data QED (no KLOE efficiency KLOE -5 HADES KLOE BaBar correction) 10 aμ,5σ APEX PHENIX Test LHCb A1 aμ,±2 σ favored -6 NA48/2 Accidental 10 E774 ae APEX 5 -7 2019 . 10 =1 2
• Begin exploring GUT range of ϵ /M -8 A0 coupling below muon threshold 10 E141 ,M .5 lower bound=0 on -9 thermal targets ↵ D • Explore part of the coupling-mass 10
Fantastic response to anticipated shift needs! Still some shifts left in March! 46 Displaced Vertices
e+ 10-4 KLOE pe− p + + -5 HADES KLOE BaBar e − 10 a ,5 APEX e PHENIX Test A1 a ,±2 favored -6 NA48/2 10 a E774 e 10µm prompt 10-7 Key capability — 2
precision tracking of -8 10 E141 displaced 1mm electron/positrons to detect displaced decays 10-9
10-10 10cm Orsay U70 Allows sensitivity to 10-11 very weak couplings 10-3 10-2 10-1 1 with ~cm decay vertex mA' [GeV]
47 HPS @ JLab: 2019
+ - ECal Compact e e spectrometer, immediately downstream of thin target in multi-GeV beam in Hall B.
+ • Low-mass, high-rate (up to 4 e
e
Silicon Vertex • PbWO4 ECal trigger eliminates Tracker 10’s MHz scattered single e-. ~1 meter + ~1 meter e
e
e
48 HPS @ JLab: 2019
ECal
+
e
e
Silicon Vertex Tracker ~1 meter + ~1 meter e
e
e
49 HPS @ JLab: 2019 arXiv:1807.11530 [hep-ex] 5 2015 Resonance Search Phys.Rev.VI. D98 CONCLUSION (2018) no.9, 091101
A resonance search for a heavy photon with a mass + between 19 and 81 MeV which decays to an e e pair 2015 Displaced+ Vertex Search was performed. A search for a resonance in the e e in- variant mass spectrum yielded no significant excess and established upper limits on the square of the coupling at 6 the level of 6 10 , confirming results of earlier searches. While not covering⇥ new territory in this short engineer- ing run, this search did establish that HPS operates as Preliminary designed and will, with future running, extend coverage 2 6 for ✏ below the level of 10 . Coverage of unexplored parameter space at smaller values of the coupling will be possible from a search for events with displaced vertices. unconstrained z vertex [mm] VII. ACKNOWLEDGMENTS Preliminary The authors are grateful for the outstanding e↵orts of the Je↵erson Laboratoryunconstrained mass [GeV] Accelerator Division and the unconstrained z vertex [mm] Hall B engineering group in support of HPS. The research reported here is supported by the U.S. Department of FIG.No 3. new The 95% sensitivity C.L. power-constrained for minimal [32] upper limits dark on photons,Energy O cebut of Science, analyses O ce ofprove Nuclear concept Physics, Of- in advance of physics runs. 2 ✏ versus A0 mass obtained in this analysis. A limit at the level fice of High Energy Physics, the French Centre National 6 of 6 10 is set. Existing limits from beam dump [21, 33– ⇥ de la Recherche Scientifique, United Kingdom’s Science 40], collider [22, 41–44] and fixed target experiments [45–48] and Technology Facilities Council (STFC), the Sesame are also shown. The region labeled “ae”isanexclusionbased project HPS@JLab funded by the French region Ile-de- on the electron g 2 [49–52] . The green band labeled “aµ ± France and the Italian Istituto Nazionale di Fisica Nu- 2 ” represents the region that an A0 can be used to explain the discrepancy between the measured and calculated muon cleare. Je↵erson Science Associates, LLC, operates the anomalous magnetic moment [16, 17]. Thomas Je↵erson National Accelerator Facility for the United States Department of Energy under Contract No. DE-AC05-060R23177.
[1] J. L. Hewett et al.,inFundamental Physics at [10] R. Essig, P. Schuster, and N. Toro, Phys. Rev. D80, the Intensity Frontier: Rockville, MD, 2011 (2012) 015003 (2009), arXiv:0903.3941 [hep-ph]. arXiv:1205.2671 [hep-ex]. [11] N. Arkani-Hamed, D. P. Finkbeiner, T. R. Slatyer, [2] R. Essig et al.,inProceedings of the 2013 Community and N. Weiner, Phys.Rev. D79,015014(2009), Summer Study on the Future of U.S. Particle Physics: arXiv:0810.0713 [hep-ph]. Snowmass on the Mississippi (CSS2013): Minneapolis, [12] M. Pospelov and A. Ritz, Phys.Lett. B671,391(2009), MN, 2013, arXiv:arXiv:1311.0029 [hep-ph]. arXiv:0810.1502 [hep-ph]. 50 [3] J. Alexander et al.,inDark Sectors 2016 Workshop: [13] D. P. Finkbeiner and N. Weiner, Phys.Rev. D76,083519 Community Report, SLAC National Accelerator Labora- (2007), arXiv:astro-ph/0702587 [astro-ph]. tory, 2016 (2016) arXiv:1608.08632 [hep-ph]. [14] P. Fayet, Phys.Rev. D70, 023514 (2004), arXiv:hep- [4] M. Battaglieri et al.,inUS Cosmic Visions: New Ideas ph/0403226 [hep-ph]. in Dark Matter 2017: Community Report, University of [15] M. Kaplinghat, S. Tulin, and H.-B. Yu, Phys. Rev. Lett. Maryland, 2017 (2017) arXiv:1707.04591 [hep-ph]. 116, 041302 (2016), arXiv:1508.03339 [astro-ph.CO]. [5] J. Jaeckel and A. Ringwald, Ann.Rev.Nucl.Part.Sci. 60, [16] M. Pospelov, Phys.Rev. D80,095002(2009), 405 (2010), arXiv:1002.0329 [hep-ph]. arXiv:0811.1030 [hep-ph]. [6] B. Holdom, Phys.Lett. B166,196(1986). [17] G. Bennett et al. (Muon G-2 Collaboration), Phys.Rev. [7] P. Galison and A. Manohar, Phys.Lett. B136,279 D73, 072003 (2006), arXiv:hep-ex/0602035 [hep-ex]. (1984). [18] M. Davier, A. Hoecker, B. Malaescu, and Z. Zhang, [8] N. Arkani-Hamed and N. Weiner, JHEP 0812,104 Eur.Phys.J. C71, 1515 (2011), arXiv:1010.4180 [hep-ph]. (2008), arXiv:0810.0714 [hep-ph]. [19] C. Cheung, J. T. Ruderman, L.-T. Wang, and I. Yavin, [9] M. Baumgart, C. Cheung, J. T. Ruderman, L.-T. Wang, (2009), 0902.3246. and I. Yavin, JHEP 0904, 014 (2009), arXiv:0901.0283 [20] D. E. Morrissey, D. Poland, and K. M. Zurek, JHEP [hep-ph]. 0907, 050 (2009), arXiv:0904.2567 [hep-ph]. HPS @ JLab: 2019 arXiv:1807.11530 [hep-ex] 5 2015 Resonance Search Phys.Rev.VI. D98 CONCLUSION (2018) no.9, 091101
A resonance search for a heavy photon with a mass + between 19 and 81 MeV which decays to an e e pair 2015 Displaced+ Vertex Search was performed. A search for a resonance in the e e in- variant mass spectrum yielded no significant excess and First physics run scheduledestablished for upper limits6/10 on the — square 8/4/2019 of the coupling at 6 the level of 6 10 , confirming results of earlier searches. ≈ While not covering⇥ new territory in this short engineer- 8 weeks at 4.55 GeV, ing4 run,weeks this search of did establishdata that = HPS0.7 operates C as(50%Preliminary typical duty cycle) designed and will, with future running, extend coverage 2 6 for ✏ below the level of 10 . Coverage of unexplored parameter space at smaller values of the coupling will be possible from a search for events with displacedHPS vertices. can also discover unconstrained z vertex [mm] VII. ACKNOWLEDGMENTSTrue muonium (ortho)! Preliminary The authors are grateful for the outstanding e↵orts of the Je↵erson Laboratoryunconstrained mass [GeV] Accelerator Division and the unconstrained z vertex [mm] Hall B engineering group in support of HPS. The research reported here is supported by the U.S. Department of FIG.No 3. new The 95% sensitivity C.L. power-constrained for minimal [32]2019 upper limits dark on photons,Energy O cebut of Science, analyses O ce ofprove Nuclear concept Physics, Of- in advance of physics runs. 2 ✏ versus A0 mass obtained in this analysis. A limit at the level fice of High Energy Physics, the French Centre National 6 of 6 10 is set. Existing limits from beam dump [21, 33– ⇥ de la Recherche Scientifique, United Kingdom’s Science 40], collider [22, 41–44] and fixed target experiments [45–48] and Technology Facilities Council (STFC), the Sesame are also shown. The region labeled “ae”isanexclusionbased project HPS@JLab funded by the French region Ile-de- on the electron g 2 [49–52] . The green band labeled “aµ ± France andthermal the Italian targets Istituto Nazionale di Fisica Nu- 2 ” represents the region that an A0 can be used to explain the discrepancy between the measured and calculated muon cleare. Je↵erson Science Associates, LLC, operates the anomalous magnetic moment [16, 17]. Thomas Je↵erson National Accelerator Facility for the United States Department of Energy under Contract No. DE-AC05-060R23177.
[1] J. L. Hewett et al.,inFundamental Physics at [10] R. Essig, P. Schuster, and N. Toro, Phys. Rev. D80, the Intensity Frontier: Rockville, MD, 2011 (2012) 015003 (2009), arXiv:0903.3941 [hep-ph]. arXiv:1205.2671 [hep-ex]. [11] N. Arkani-Hamed, D. P. Finkbeiner, T. R. Slatyer, [2] R. Essig et al.,inProceedings of the 2013 Community and N. Weiner, Phys.Rev. D79,015014(2009), Summer Study on the Future of U.S. Particle Physics: arXiv:0810.0713 [hep-ph]. Snowmass on the Mississippi (CSS2013): Minneapolis, [12] M. Pospelov and A. Ritz, Phys.Lett. B671,391(2009), MN, 2013, arXiv:arXiv:1311.0029 [hep-ph]. arXiv:0810.1502 [hep-ph]. 50 [3] J. Alexander et al.,inDark Sectors 2016 Workshop: [13] D. P. Finkbeiner and N. Weiner, Phys.Rev. D76,083519 Community Report, SLAC National Accelerator Labora- (2007), arXiv:astro-ph/0702587 [astro-ph]. tory, 2016 (2016) arXiv:1608.08632 [hep-ph]. [14] P. Fayet, Phys.Rev. D70, 023514 (2004), arXiv:hep- [4] M. Battaglieri et al.,inUS Cosmic Visions: New Ideas ph/0403226 [hep-ph]. in Dark Matter 2017: Community Report, University of [15] M. Kaplinghat, S. Tulin, and H.-B. Yu, Phys. Rev. Lett. Maryland, 2017 (2017) arXiv:1707.04591 [hep-ph]. 116, 041302 (2016), arXiv:1508.03339 [astro-ph.CO]. [5] J. Jaeckel and A. Ringwald, Ann.Rev.Nucl.Part.Sci. 60, [16] M. Pospelov, Phys.Rev. D80,095002(2009), 405 (2010), arXiv:1002.0329 [hep-ph]. arXiv:0811.1030 [hep-ph]. [6] B. Holdom, Phys.Lett. B166,196(1986). [17] G. Bennett et al. (Muon G-2 Collaboration), Phys.Rev. [7] P. Galison and A. Manohar, Phys.Lett. B136,279 D73, 072003 (2006), arXiv:hep-ex/0602035 [hep-ex]. (1984). [18] M. Davier, A. Hoecker, B. Malaescu, and Z. Zhang, [8] N. Arkani-Hamed and N. Weiner, JHEP 0812,104 Eur.Phys.J. C71, 1515 (2011), arXiv:1010.4180 [hep-ph]. (2008), arXiv:0810.0714 [hep-ph]. [19] C. Cheung, J. T. Ruderman, L.-T. Wang, and I. Yavin, [9] M. Baumgart, C. Cheung, J. T. Ruderman, L.-T. Wang, (2009), 0902.3246. and I. Yavin, JHEP 0904, 014 (2009), arXiv:0901.0283 [20] D. E. Morrissey, D. Poland, and K. M. Zurek, JHEP [hep-ph]. 0907, 050 (2009), arXiv:0904.2567 [hep-ph]. Dark Sectors at JLab: 2019
Two Jefferson Lab experiments that address dark matter/dark sector physics goals have upcoming runs in 2019!
APEX — “A Prime EXperiment" in Hall A (February-March run!)
HPS — “Heavy Photon Search” in Hall B (June-August run!)
Exciting data expected this year! Still plenty of room to get involved
51 Organizing the Physics (Vector kinetic mixing as an example — most models work similarly)
DM and Mediator Production JLab and other efforts in US as well! Contact operator
heavy DM production A′ (off-shell A’)
¯ Resonant DM DM = 2 m production Aʹ (on-shell A’) m 2 me Visibly decaying mediator;
Dark photon mass photon Dark Near-threshold DM production (off-shell mediator) 0 Dark matter mass e+ Search for both the mediator A′ and DM itself! e 52 Light Dark Matter Searches at beam dumps Dark Matter interacts weakly
⇒ passes through anything! 2
10 m 10 m e Dirt can use proton beams too! Beam Dump Detector Produce DM through …detect its scattering the portal… downstream Optional Detector Shielding Izaguirre, Krnjaic, 1m Schuster & NT PRD.88.114015 and 1m 1403.6826 e e 1m 53
FIG. 1: Schematic experimental setup. A high-intensity multi-GeV electron beam impinging on a beam dump pro- duces a secondary beam of dark sector states. In the basic setup, a small detector is placed downstream so that muons and energetic neutrons are entirely ranged out. In the con- crete example we consider, a scintillator detector is used to study quasi-elastic -nucleon scattering at momentum trans- fers > 140 MeV, well above radiological backgrounds, slow neutrons,⇠ and noise. To improve sensitivity, additional shield- ing or vetoes can be used to actively reduce cosmogenic and other environmental backgrounds. .
e e a) A0
Z
b)
A0 p, n Z
FIG. 2: a) ¯ pair production in electron-nucleus collisions via the Cabibbo-Parisi radiative process (with A0 on- or o↵- shell) and b) scattering o↵ a detector nucleus and liberating a constituent nucleon. For the momentum transfers of inter- est, the incoming resolves the nuclear substructure, so the typical reaction is quasi-elastic and nucleons will be ejected. Beam Dump eXperiment @ JLab
BDX (parasitic behind JLab Hall A dump)
See: arXiv:1712.01518
Leptophilic DM, Most Conservative: D = 0.5, mA' = 3 m Fermion DM, Above LSND Threshold, m = 68 MeV, D = 0.1 10-7 10-3
BaBar BaBar 10-4 10-8
5 (g- 2) > 2 -5 10 K+ 4 ) obs ± 2 -9 (g- 2) E137 A' 10
m -6 / 10 Scalar BDX@JLab m 22 ( -10 10 EOT 10 3, 10, 20 events 10-7 D Density 0.05 0.10 0.50 1 Relic 2 Borexino mA' (GeV)
Fermion E137 Fermion DM, Above LSND Threshold, m = 68 MeV, = -11
= 10 Density y Relic
10-12 BDX@JLab 1022 EOT 3, 10, 20 events New sensitivity to dark 10-13 1 10 102 matter production! m [MeV] Thermal Relic DM, Most Conservative = 0.5, m = 3 m 54
Figure 35: Same as Fig. 34 only here m =68MeVandweadopt↵D =0.1and ↵D = ↵EM for the two panels. This choice of m represents the kinematic limit beyond which LSND can no longer produce pairs of via ⇡0 . Note that for ! mA0 < 2m the dark photon will no longer decay to DM pairs and may be constrained by visible searches, but this is model dependent. 68
Figure 33: Red curves show 3, 10, and 20 event for BDX yield projections for electron scattering with a 300 MeV energy threshold for thermal relic DM in two representative scenarios. Top: thermal relic DM coupled to a leptophilic U(1)e µ gauge boson (A0). Bottom: here the A0 is a kinetically mixed dark photon coupled to the electromagnetic current. Here the thermal target — where the model predicts the correct observed DM abundance — is shown in solid black. 66 Conclusions Testing the dark sector idea is a critical step in our broadening effort to understand the particle nature of dark matter
• Sharp science case with vibrant community • Important and well-defined parameter space sensitivity milestones (i.e. thermal dark matter, GUT strength couplings, DM self-interactions…) • Dedicated “dark force” experiments (APEX & HPS) collecting their first signifiant data in 2019! • Lively activity towards future experimental efforts to produce dark matter in electron beams