The Precious Life of Muons A seminar by

The Precious Life of Muons A seminar by Filippo Capurso as part of PHY 489 - Special Topics in Particle Physics KAIST – Fall Semester, 2017 1 st December 2017

Overview • The history behind the muon discovery and why it is underestimated • The muons around us and their properties • The current uses of muons and why their properties are valuable • The potential use of muons in particle accelerators and how they could save particle physics The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

3 The discovery of the Muon The Lord Kelvin William Thomson, 1 st Baron Kelvin “ There is nothing new to be discovered in physics now. All that remains is more and more precise measurement ” 1900 The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 https: //en. wikipedia. org/wiki/William_Thomson, _1 st_Baron_Kelvin 1 st Dec, 2017

4 Source: http: //www. economist. com/blogs/graphicdetail/2012/07/daily-chart-1 The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

5 Carl David Anderson Seth Neddermeyer Shower of Particles Lead / Platinum Greater ionization than e– https: //en. wikipedia. org/wiki/Car l_David_Anderson 1936 ? ? ? https: //en. wikipedia. org/wiki/Set h_Neddermeyer Based on electron charge data and calculations by Bethe and Heitler, stated the hypothesis of a heavier electron: the Mesotron The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

6 J. C. Street and E. C. Stevenson’s Cloud Chamber A shower produced by a single electron 1937 A complex shower phenomenon https: //journals. aps. org/pr/pdf/10. 1103/Phys. Rev. 49. 425 The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

7 J. C. Street and E. C. Stevenson’s Cloud Chamber The path of a proton 1937 Paths of a muon https: //journals. aps. org/pr/pdf/10. 1103/Phys. Rev. 52. 1003 The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

8 Hideki Yukawa Predicted particles ~200 times heavier than an electron to explain the nuclear force and named them “mesons”. The muon was therefore considered as the predicted meson. César Lattes, Giuseppe Occhialini and Cecil Powell discovered the real Yukawa particle, the π-meson. https: //en. wikipedia. org/wiki/Hideki_Yukawa 1935 The muon was differentiated by it with the name μ-meson. The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1947 1 st Dec, 2017

9 With the definition of the Standard Model, the muon is removed from the handron and meson list, and finally recognised as a fundamental particle, a lepton. https: //en. wikipedia. org/wiki/Standard_Model After almost 40 years! 1970 s The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

10 1. Was destined to be ignored and underrated Israel Isaac Rabi 2. Is a fundamental particle (not composed by quarks) “ Who ordered that? ” https: //en. wikipedia. org/wiki/Isidor_Isaac_Rabi Muon characteristics’ summary The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

11 The muons around us Nature and Properties – μ Mass m = 105. 6583715 ± 0. 0000035 Me. V ( ≈ 206. 8 times the mass of e–) + μ Spin = ½ Charge = – 1 q Mean life τ = (2. 1969811 ± 0. 0000022) μs The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

12 Sources of cosmic ray muons (99. 9877%) π0 π+ π– γ+γ μ+ + ν μ μ– + νμ http: //feynman. phy. ulaval. ca/marleau/pp/16 neutrinos fermilab/Neutrinos_Fermilab_CG-LH-MPL. html The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 μ+ μ– e+ + ν e + ν μ e– + ν e + ν μ https: //i. stack. imgur. com/AIcur. png 1 st Dec, 2017

13 Sources of cosmic ray muons http: //hyperphysics. phy-astr. gsu. edu/hbase/Astro/cosmic. html The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

14 Pion mean lifetime τ = 26. 02 ± 0. 04 ns Muon mean lifetime τ ≈ 2. 197 μs Speed of Light c ≈ 299’ 792’ 458 m/s Max total distance = V · t ≈ 666. 44 m But muons fall hit the earth surface at an average rate close to 10’ 000 particles per m 2 per minute How? ? https: //scied. ucar. edu/atmosphere-layers The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

15 Applying Relativity laws Kinetic Energy Time Dilatation K = γ·mc 2 + mc 2 K ≈ 2 Ge. V t’ = γ·t Ratio with speed of light γ= 1 √(1 – β 2) β = v/c β ≈ 0. 994 ± 0. 005 The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 L = v·t’ Length Contraction l’·γ = l Found to travel on average between 8. 7 km and 15 km 1 st Dec, 2017

16 Why do muons pass through bodies so easily? http: //www. quantumdiaries. org/2010/04/04/q ed-%CE%BC-introducing-the-muon/ http: //inspirehep. net/record/884672/plots The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

17 http: //www. lhc-closer. es/webapp/files/1435504295_f 9 f 979010 d 94925277 e 1 a 790 b 96 f 7 b 19. jpg The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

18 1. Was destined to be ignored and underrated 2. Is a fundamental particle (not composed by quarks) 3. Has a short lifetime, but can travel far at speeds approaching c Muon characteristics’ summary The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

19 Current uses of muons Heavy material detection and body density analysis Geophysical radiography https: //cdn. images. express. co. uk/img/dynamic/78/590 x/sec ondary/Bali-volcano-eruption-at-night-1143661. jpg The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 Scattering tomography http: //physicsbuzz. physicscentral. com/2015/08/ whats-more-radioactive-than-nuclear. html 1 st Dec, 2017

20 Geophysical radiography using cosmic ray muons Illustration of cosmic ray muons entering the Giza Pyramid (Egypt) http: //www. lepoint. fr/images/2016/05/04/3834744 lpw-3834759 -article-jpg_3528603_660 x 281. jpg Longitudinal section of Agua Negra tunnel (Chile) https: //www. aps. org/units/fip/newsletters/201202/bertou. cfm The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

21 Geophysical radiography using cosmic ray muons Detection of muons passing through La Soufrière of Guadeloupe (France) Change in muon flux passing through the Asama volcano (Japan) https: //academic. oup. com/gji/article/183/3/1348/638804#10895302 http: //onlinelibrary. wiley. com/doi/10. 1029/2009 GL 039448/full The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

22 Scattering tomography for heavy material detection Diagram of muon scattering when Prototype of a muon scatter detector (Italy) passing through a high density body http: //www. science 20. com/quantum_diaries_survivor/muo n_tomography_who_leading_research http: //www. pd. infn. it/~dorigo/tomo_piombo 1. jpg The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

23 Scattering tomography for heavy material detection Set up for scattering tomography of the Fukushima Daiichi (Japan) https: //www. researchgate. net/publication/257949382_Imaging_Fukushima_Daiichi_reactors_with_muons The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

24 Scattering tomography for heavy material detection http: //iopscience. iop. org/article/10. 1 088/1361 -6633/80/2/026301 Identification of a lead body in a car https: //www. scientificamerican. com/article/muons-for-peace/ The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

25 Scattering tomography for structure analysis Tomography of a valve in its two states Tomography of a mock-up of the cupola wall of Santa Maria del Fiore (Italy) http: //www. sciencemag. org/news/2015/06/givingbuildings-cosmic-ct-scan The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 https: //arxiv. org/pdf/1601. 01291. pdf 1 st Dec, 2017

26 1. Was destined to be ignored and underrated 2. Is a fundamental particle (not composed by quarks) 3. Has a short lifetime, but can travel far at speeds approaching c 4. Is affected only minimally by external factors Muon characteristics’ summary The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

27 The limit of Particle Accelerators The Muon as the saviour of Experimental Particle Physics • We reached a stop in Experimental Particle Physics • The last particle of the Standard Model took more than 50 years to be discovered Ø Byron Asymmetry: why is there more matter than antimatter? • But there are still several unanswered facts and questions Ø Dark Matter: where is it and what is it? Ø Neutrino mass problem: why are they so light? Ø Quantum nature of gravity: gravitons? Ø And more… The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

28 There are several theories, but they have to be proved experimentally Large Hadron Collider (France-Switzerland) https: //www. symmetrymagazine. org/article/march-2015/the-lhc-does-a-dry-run The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

29 Numbers of the world’s largest particle collider The reachable energy in particle colliders is proportional to two things: Large Hadron Collider • R = the radius of the accelerator ≈ 2. 93 km • B = the strength of the magnetic field 8. 3 Tesla The LHC managed to accelerate protons up to 6. 5 Te. V The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 Record collisions of 13 Te. V 1 st Dec, 2017

30 The truth about collisions energy The LHC uses heavy stable particles: Protons But protons, being hadrons, are made up of quarks and lose energy when breaking upon impact Collision with energy loss Clean collisions are obtained when colliding leptons as they do not break in their sub-components The heaviest fundamental particles are electrons and positrons Having a mass 1836 times smaller than the proton mass, they are exposed to synchrotron radiation Lower acceleration 0. 114 Te. V The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

31 A new alternative! 1. Was destined to be ignored and underrated • Need a new particle that we have not yet considered 2. Is a fundamental particle (not composed by quarks) • Must create clean collisions 3. 4. • Has a short lifetime, but can travel far at speeds approaching c Must be able to remain stable until collision • Is not affected by synchrotron radiation μ Is affected only minimally by external factors The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

32 A new type of collider: The Muon Collider Muon Ionization Cooling Experiment At 6. 5 Te. V, a muon would be able to live for 135’ 000 microseconds Would be able to circle the LHC 1500 times! https: //blogs-images. forbes. com/startswithabang/files/2017/04/15 NQ 7 Aib. Zh 4 N 1_u. Ce-g 3 Wh. A. jpg? width=960 The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

33 1. Is underrated because of its history 2. Was the second fundamental particle to be ever discovered 3. Proves relativity constantly by reaching the Earth’s soil 4. Thanks to its material penetration characteristics, can be used to monitor and improve the world around us ± μ 5. Could be the saviour of experimental particle physics Conclusion The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017

34 Thank you for your attention! Ask Questions The Precious Life of Muons, by Filippo Capurso – KAIST, PH 489 1 st Dec, 2017