The Precious Life of Muons A seminar by Filippo Capurso as part of PHY489 - Special Topics in Particle Physics KAIST – Fall Semester, 2017 1 st December 2017
2 ì 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, PH489 1st Dec, 2017
3 The discovery of the Muon The Lord Kelvin William Thomson, 1st Baron Kelvin “ There is nothing new to be discovered in physics now. All that remains is more and more precise measurement ” 1900 h@ps://en.wikipedia.org/wiki/William_Thomson,_1st_Baron_Kelvin The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
4 Source: h@p://www.economist.com/blogs/graphicdetail/2012/07/daily-chart-1 The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
5 Carl David Anderson Seth Neddermeyer Shower of Particles Lead / Platinum Greater ionization than e – ? ? ? h@ps://en.wikipedia.org/wiki/ h@ps://en.wikipedia.org/wiki/ Seth_Neddermeyer Carl_David_Anderson Based on electron charge data and calculations by Bethe and Heitler, stated the hypothesis of a 1936 heavier electron: the Mesotron The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
6 J. C. Street and E. C. Stevenson’s Cloud Chamber A shower produced by a single electron A complex shower phenomenon 1937 h@ps://journals.aps.org/pr/pdf/10.1103/PhysRev.49.425 The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
7 J. C. Street and E. C. Stevenson’s Cloud Chamber The path of a proton Paths of a muon 1937 h@ps://journals.aps.org/pr/pdf/10.1103/PhysRev.52.1003 The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st 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 La@es, Giuseppe Occhialini and Cecil Powell discovered the real Yukawa particle, the π-meson . h@ps://en.wikipedia.org/wiki/Hideki_Yukawa The muon was differentiated by it with the name µ-meson . 1935 1947 The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st 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 . After almost 40 years! h@ps://en.wikipedia.org/wiki/Standard_Model 1970s The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
10 1. Was destined to be ignored and Israel Isaac Rabi underrated 2. Is a fundamental particle (not composed by quarks) “ Who ordered that? ” h@ps://en.wikipedia.org/wiki/Isidor_Isaac_Rabi Muon characteristics’ summary The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
11 ì The muons around us Nature and Properties µ – Mass m = 105.6583715 ± 0.0000035 MeV ( ≈ 206.8 times the mass of e – ) Charge = –1 q µ + Spin = ½ Mean life τ = (2.1969811 ± 0.0000022) µ s The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
12 Sources of cosmic ray muons (99.9877%) µ + e + + ν e + ν µ π 0 γ + γ π + µ + + ν µ µ – e – + ν e + ν µ π – µ – + ν µ h@p://feynman.phy.ulaval.ca/marleau/pp/ h@ps://i.stack.imgur.com/AIcur.png 16neutrinosfermilab/Neutrinos_Fermilab_CG-LH- MPL.html The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
13 Sources of cosmic ray muons h@p://hyperphysics.phy-astr.gsu.edu/hbase/Astro/cosmic.html The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
14 Pion mean lifetime τ = 26.02 ± 0.04 ns Muon mean lifetime τ ≈ 2.197 µ s 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?? h@ps://scied.ucar.edu/atmosphere-layers The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
15 Applying Relativity laws Kinetic Energy Time Dilatation t ’ = γ ·t K = γ ·mc 2 + mc 2 K ≈ 2 GeV L = v·t ’ Ratio with speed of light Length Contraction 1 l ’· γ = l γ = √ (1 – β 2 ) Found to travel on β = v/c β ≈ 0.994 ± 0.005 average between 8.7 km and 15 km The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
16 Why do muons pass through bodies so easily? h@p://www.quantumdiaries.org/2010/04/04/ qed-%CE%BC-introducing-the-muon/ h@p://inspirehep.net/record/884672/plots The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
17 h@p://www.lhc-closer.es/webapp/files/1435504295_f9f979010d94925277e1a790b96f7b19.jpg The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st 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, PH489 1st Dec, 2017
19 Current uses of muons Heavy material detection and body density analysis Geophysical radiography ScaZering tomography h@ps://cdn.images.express.co.uk/img/dynamic/78/590x/ h@p://physicsbuzz.physicscentral.com/2015/08/ secondary/Bali-volcano-eruption-at-night-1143661.jpg whats-more-radioactive-than-nuclear.html The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
20 Geophysical radiography using cosmic ray muons Illustration of cosmic ray muons entering the Giza Pyramid (Egypt) h@p://www.lepoint.fr/images/2016/05/04/3834744lpw-3834759-article-jpg_3528603_660x281.jpg Longitudinal section of Agua Negra tunnel (Chile) h@ps://www.aps.org/units/fip/newsle@ers/201202/bertou.cfm The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
21 Geophysical radiography using cosmic ray muons Change in muon flux passing Detection of muons passing through La through the Asama volcano (Japan) Soufrière of Guadeloupe (France) h@ps://academic.oup.com/gji/article/183/3/1348/638804#10895302 h@p://onlinelibrary.wiley.com/doi/10.1029/2009GL039448/full The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
22 Scattering tomography for heavy material detection Diagram of muon sca@ering when Prototype of a muon sca@er detector (Italy) passing through a high density body h@p://www.science20.com/quantum_diaries_survivor/ muon_tomography_who_leading_research h@p://www.pd.infn.it/~dorigo/tomo_piombo1.jpg The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
23 Scattering tomography for heavy material detection Set up for sca@ering tomography of the Fukushima Daiichi (Japan) h@ps://www.researchgate.net/publication/257949382_Imaging_Fukushima_Daiichi_reactors_with_muons The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
24 Scattering tomography for heavy material detection h@p://iopscience.iop.org/article/ 10.1088/1361-6633/80/2/026301 Identification of a lead body in a car h@ps://www.scientificamerican.com/article/muons-for-peace/ The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
25 Scattering tomography for structure analysis Tomography of a mock-up of the cupola wall of Santa Maria del Fiore (Italy) Tomography of a valve in its two states h@p://www.sciencemag.org/news/2015/06/giving- buildings-cosmic-ct-scan h@ps://arxiv.org/pdf/1601.01291.pdf The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st 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, PH489 1st Dec, 2017
27 ì 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 ma@er than antima@er? Ø Dark Ma@er: where is it and what is it? • But there are still several unanswered facts and questions 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, PH489 1st Dec, 2017
28 There are several theories, but they have to be proved experimentally Large Hadron Collider (France-Swi\erland) h@ps://www.symmetrymagazine.org/article/march-2015/the-lhc-does-a-dry-run The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
29 Numbers of the world’s largest particle collider Large The reachable energy in particle Hadron Collider colliders is proportional to two things: ≈ 2.93 km • R = the radius of the accelerator • B = the strength of the magnetic field 8.3 Tesla Record collisions The LHC managed to accelerate of 13 TeV protons up to 6.5 TeV The Precious Life of Muons, by Filippo Capurso – KAIST, PH489 1st Dec, 2017
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