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Any Light Particle Search II ALPS II @ DESY Axel Lindner DESY IAXO workshop, Frascati, 18 April 2016 ALPS II motivation: a bibliometric look > Key words “axion”, “relaxion”, “axion-like particle”, “WISP” try to restrict analysis to “physics” > WoS, Scopus > Significant increase in WISP-related publications! Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 2 ALPS II physics motivation: theory > Axion cosmology: arXiv:1508.06917 [hep-lat] lattice QCD calculations are used to determine the amount of axion Dark Matter today via the temperature dependence of the axion mass. > Baryon genesis from the axion: Phys.Rev.Lett. 113 (2014) 17, 171803 this cold genesis requires a coupling of the Higgs to a new scalar with O(100 GeV) mass (to be tested at LHC!). > A naturally small electroweak scale: arXiv:1506.09217 [hep-ph] could be explained by a cosmological Higgs-axion interplay. The symmetry breaking scale fa may be at the same time the see-saw scale explaining the active neutrino masses, mA ~ mν ~ 1/fa , JHEP 1406 (2014) 037 There are viable theoretical models addressing fundamental problems in cosmology and particle physics based on axion-like particles or other WISPS. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 3 ALPs in the sky (1) > Axion-like particles might explain the apparent transparency of the universe for TeV photons: TeV photons may “hide” as axions. M. Meyer, 7th Patras Workshop on Axions, WIMPs and WISPs, 2011 Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 4 ALPs in the sky (1) > New FERMI limits on ALPS from search for irregularities in the spectrum of NGC1275 (http://arxiv.org/abs/1603.06978): Do we start to zoom into the properties of the axion-like particle explaining the TeV transparency hint? Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 5 ALPs in the sky (2) > Hints for ALPS from developments of stars (M. Giannotti, I. Irastorza, J. Redondo, A. Ringwald, http://arxiv.org/abs/1512.08108): Indications for “BSM energy losses” of different kinds of stars could be consistently explained by one electron coupling axion-like particle coupling to photons and electrons. It could be the same ALP as the one explaining the “TeV transparency”. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 6 Purely laboratory experiments Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 7 ALPS I 2007-2010: our starting point (PLB Vol. 689 (2010), 149, or http://arxiv.org/abs/1004.1313) > Unfortunately, no light was shining through the wall! laser hut HERA dipole 3.5·1021 1/s detector < 10-3 1/s > The most sensitive WISP search experiment in the laboratory (up to 2014). Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 8 The ALPS II challenge > Improve on the ALPS-photon-photon coupling strength g by > 1,000. The experiment measures a rate ~ g4: > The experimental sensitivity is to increased by a factor 1012! Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 9 laser hut > Laser with optical cavity to recycle laser power, switch from 532 nm to 1064 nm, increase effective power from 1 to 150 kW. HERA dipole > Magnet: upgrade to 10+10 straightened HERA dipoles instead of ½+½ used for ALPS I. detector > Regeneration cavity to increase WISP-photon conversions, single photon counter (superconducting transition edge sensor). Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 10 All set up in a clean environment! Prospects for ALPS II @ DESY ALPS II is realized in stages (JINST 8 (2013) T09001) ALPS I: basis of success was the optical resonator in front of the wall. > ALPS IIa Optical resonator to increase effective light flux by recycling the laser power Optical resonator to increase the conversion probability WISP→ Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 11 ALPS II is realized in stages (JINST 8 (2013) T09001) ALPS I: basis of success was the optical resonator in front of the wall. > ALPS IIa The optics concept was invented three times independently: • Hoogeveen F, Ziegenhagen T. Optical resonator to Nucl. Phys.Optical B358:3resonator (1991) to increase the conversion increase effective • Fukuda Y, Kohmoto T, Nakajima Si, Kunitomo M. probability light flux by Prog. Cryst. Growth Charact.Mater. 33:363 (1996) recycling the van laser • Sikivie P., Tanner D.B., Bibber WISP→ K. power Phys.Rev.Lett. 98 (2007) Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 12 ALPS II is realized in stages (JINST 8 (2013) T09001) ALPS I > ALPS IIa > ALPS IIc 20 HERA dipoles, 200 m long Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 13 The ALPS II challenge > Photon regeneration probability: > ALPS II: FPC = 5000, FRC = 40000 (power build-up in the optical resonators) B = 5.3 T, l = 88 m (two times) P = 6·10-23 , 30 photons per hour P = 6·10-27 , 2 photons per month Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 14 ALPS II: main experimental challenges > HERA dipole magnets: straighten the cold mass cheap and reliably to increase the 35 mm aperture to 50 mm. > Optics: construct and operate two 100 m long optical resonators of high quality which are mode matched and aligned to better than 10 µrad. > Detector: characterize and operate a superconducting Transition Edge Sensor (25µm·25µm·20nm) at 80 mK to count single 1064 nm photons. DESY expertise, but mostly retired experts only. Adapt LIGO techniques, AEI Hanover, U. of Florida, DESY DESY, HH, Mainz, in close collaboration with NIST (Boulder) and PTB Berlin Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 15 ALPS II optics Production cavity, infrared Wall Regeneraton cavity, locked with green light. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 16 ALPS II optics Production cavity, infrared Wall Regeneraton cavity, locked with green light. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 17 ALPS II optics Production cavity, infrared Wall Regeneraton cavity, locked with green light. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 18 ALPS II optics > Pound-Drever hall “locking“ to compensate for seismic noise fluctuations. ok > Differential wavefront sensing for auto-aligning the optical axis of the cavity. ok Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 19 ALPS II optics > Generate and adapt 532 nm light to control the regeneration cavity behind the wall. (ok) Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 20 ALPS II optics > Feed 532 nm light into the regeneration cavity with “perfect” filtering out 1064 nm light. (ok) Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 21 ALPS II optics > Pound-Drever hall “locking“ to compensate for seismic noise fluctuations. (ok) > Differential wavefront sensing for auto-aligning the optical axis of the cavity. (ok) Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 22 ALPS II optics > Design and build central breadboard with two flat mirrors fixed and aligned to an accuracy better than 10 µrad. (ok) Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 23 ALPS II optics > Guide 1064 nm signal photons into the detector with “perfect” filtering out 532 nm light. (ok) Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 24 The photon source The laser has been developed for LIGO: 35 W, 1064 nm, M2<1.1 based on 2 W NPRO by Innolight/Mephisto (Nd:YAG (neodymiumdoped yttrium aluminium garnet) Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 25 The central optics 0,0006 mm Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 26 Status of optics (1) Before late 2015 faulty cavity mirrors exceeding the roughness specification prevented a stable cavity operation. New mirrors were ordered to test the 20 m setup ALPS IIa with a confocal cavity: Goals: > Understand properties of the cavity. > Be able to lock the cavity for “infinity”. > Get the auto-alignment system into operation. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 27 Status of optics (2) > Understand properties of the cavity. There are 200 ppm unexplained losses which will probably vanish once we operate the cavity in vacuum. > Be able to lock the cavity for “infinity”. > Get the auto-alignment system into operation. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 28 Status of optics (3) > Understand properties of the cavity. > Be able to lock the cavity for “infinity”. The seismic noise in the ALPS IIa lab can be handled by the control system. > Get the auto-alignment system into operation. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 29 Status of optics (4) > Understand properties of the cavity. > Be able to lock the cavity for “infinity”. > Get the auto-alignment system into operation. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 30 Optics: next steps > Implement the a simplified version of the central breadboard. > Operate 10 m production cavity. > Operate production cavity in vacuum. > High power tests in vacuum. > Implement prototype of central breadboard. > Test the (simultaneous) operation of both cavities. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 31 Control loops for the ALPS II PC at work control signal error signal Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 32 Control loops for the ALPS II PC at work Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 33 ALPS II detector Transition Edge Sensor (TES) Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 34 ALPS II detector Transition Edge Sensor (TES) ΔT 100 µK Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 35 ALPS II detector Transition Edge Sensor (TES) ΔT 100 µK ΔR 1 Ω Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 36 ALPS II detector Transition Edge Sensor (TES) ΔT 100 µK ΔR 1 Ω ΔI 70 nA Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 37 ALPS II detector Transition Edge Sensor (TES) ΔT 100 µK ΔR 1 Ω ΔI 70 nA > Expectation: very high quantum efficiency, also at 1064 nm, very low noise. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 38 ALPS II: Transition Edge Sensor (TES) 25 x 25 µm2 8 µm Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 39 ALPS II: Transition Edge Sensor (TES) > Tungsten film kept at the transition to superconductivity at 80 mK. > Sensor size 25µm x 25µm x 20nm. > Single 1066 nm photon pulses! > Energy resolution 8%. > Dark background 10-4 counts/second. > Ongoing: background studies, optimize fibers, minimize background from ambient thermal photons. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 40 ALPS II: heterodyne detection under study in Florida > Mix signal with a local oscillator and look for beat-signal. > Strong requirements on phase stabilities. Courtesy Guido Mueller Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 41 ALPS II schedule (rough) 2015 ALPS IIa 2016 2017 2018 2019 Install. (without magnets) Runs risk assessments ALPS IIc Closure of the LINAC tunnel of the European XFEL under construction at DESY. ALPS IIa today ALPS IIc in 2019 in the HERA tunnel Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 42 ALPS II schedule (rough) Latest input from QED VMB studies on the ALPS IIc design! 2015 ALPS IIa 2016 2017 2018 2019 Install. (without magnets) Runs risk assessments ALPS IIc Closure of the LINAC tunnel of the European XFEL under construction at DESY. ALPS IIa today ALPS IIc in 2018 in the HERA tunnel Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 43 The axion-like particle landscape Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 44 ALPS II sensitivity > Well beyond current limits. > Aim for data taking in 2019. ALPS II > QCD axions not in reach. > Able to probe hints from astrophysics. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 45 Beyond ALPS II > Rough estimation with some crucial parameters: Photon >Exp. QCD axions not Photon in reach. B flux E (eV) (T) > Able to probe (1/s) hints from astrophysics. 3.5·1021 ALPS I L (m) B·L (Tm) PB reg.cav. Sens. (rel.) Mass reach (eV) 2.3 5.0 4.4 22 1 0.0003 0.001 ALPS II 1·1024 1.2 5.3 106 468 40,000 1 0.0002 “ALPS III” 1·1025 1.2 15 400 6000 100,000 25-30 0.0001 Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 46 Beyond ALPS II > QCD axions not in reach. > Could measure properties of a lightweight ALPs discovered by IAXO! ALPS III Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 47 Summary > In addition to axions, also axion-like particles (ALPs) are going strong. ALPs are expected in extensions of the Standard Model. Astrophysics phenomena might point at the existence of ALPs. ALPs might also constitute the dark matter. > ALPS II has a sufficient sensitivity to discover axion-like particles or other WISPs, especially in the region hinted at by astrophysics. ALPS II will conduct a first hidden photon search in 2017. The full experiment could be ready in 2019. > On the longer run, options for an “ALPS III” should be explored. > In WISP physics, haloscopes like IAXO and purely laboratory based experiments like ALPS II nicely complement each other! Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 48 Lessons learned from ALPS II It is fascinating physics nicely complementing other particle physics enterprises: > New ideas are realized by combining different expertise. Particle physics (DESY) and optics (LIGO) join forces. > Young people have fun taking responsibilities at ALPS II. Four Ph.D. theses and two postdoc careers since the start in 2011. At present eight Ph.D. and six postdocs are at work. > Funding works out! Once ALPS II preparation had started seriously, external contributions got approved! Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 49 ALPS II and IAXO: a likely case > ALPS II discovery an axion-like particle. The coupling strength to photons will be determined. The mass might be measured or limited. > IAXO will see such axion-like particles produced in the sun. Other couplings (electron, nucleon) could be probed. Solar physics cold be probed. > With ALPS II and IAXO data we could narrow down the many opportunities of beyond-the-standard-model theories. Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 50 ALPS II and IAXO: Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 51 ALPS II and IAXO: an equally likely case > ALPS II does not see an axion-like particle. > IAXO is baldy required to solve the astroparticle physics riddles hinting at axion-like particles. > With IAXO and ALPS III data we could narrow down the many opportunities of beyond-the-standard-model theories. Thank your for your attention! Axel Lindner | ALPS II | IAXO Workshop April 2016 | Page 52