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Jan 13, 2024 •40 likes •370 views

F r o m Q u a r k s t o Q u a s a r s Outline: Start Here End Here (Particle Physics) (Cosmology) Dr. Peter Skands CERN Theoretical Physics Dept Hvem er jeg? Lste fysik-astronomi p KU (cand scient: 5 r) Lunds Universitet:

  1. F r o m Q u a r k s t o Q u a s a r s Outline: Start Here End Here (Particle Physics) (Cosmology) Dr. Peter Skands CERN Theoretical Physics Dept

  2. Hvem er jeg? Læste fysik-astronomi på KU (cand scient: 5 år) → Lunds Universitet: teoretisk fysik (PhD: 3 år) 2 P. S k a n d s

  3. Hvem er jeg? Læste fysik-astronomi på KU (cand scient: 5 år) → Lunds Universitet: teoretisk fysik (PhD: 3 år) → Fermilab (Chicago) “Post Doc”: 2 år “Scientist”: 3 år Nu: CERN … 3 P. S k a n d s

  4. CERN: European Organization for Nuclear Research 20 European Member States and around 60 other countries ~ 10 000 scientists work at CERN. 27 Flags of CERN’s Member States Yearly budget ~ 1 billion CHF ~ 6 mia DKR 4 P. S k a n d s

  5. What goes on at CERN LHC Collision at 7 TeV ATLAS, March 2010

  6. Nutshell Theory Experiment Adjust this to agree with this → Science

  7. In Practice PYTHIA … VINCIA Simulation Codes Experimental Data → Simulated Particle Collisions → Published Data Points “Events” “Histograms”

  8. Min Forskning Teorien om den stærke kernekraft: Kvante-Chromodynamik (QCD) + Hadroner = bundne tilstande af kvarker (og antikvarker) Kvarker og Gluoner Mesoner (kvark-antikvark): pioner, kaoner, ρ mesoner, … Baryoner (triple-kvark): protoner, neutroner, hyperoner, … Bremsstrahlung Når du sparker en kvark, stråler den gluoner (Jvf elektriske ladninger, der stråler fotoner) Hadronisering Når kvarker og gluoner bliver ‘kolde’ bindes de i hadroner Der opstår ‘gluon-strenge’ mellem dem, som bryder op Den process forsøger vi at modellere og forstå ~ 1fm “Monte Carlo event generators” = “1 fermi” - Kvante-sandsynligheder → tilfældige tal → tilfældige begivenheder, som i eksperimentet ~ en ‘virtuel accelerator’ - Used by experiments to give “theory predictions”, to compare with data - Used to design and optimize detectors and analysis strategies - Used by theorists to explore new solutions, new ideas, new physics Not a computer scientist. But the numerical calculations I (want to) do require a lot of power → distributed computing: farms / GRID / clouds. 8 P. S k a n d s

  9. L H C @ h o m e 2 . 0 Te s t 4 T h e o r y - A V i r t u a l A t o m S m a s h e r p p LHC Physics Center at CERN ������������������������������������������ ��������������������������������� ����������������������������������������������������������������������������������� �������������� �������������������������� ������������� O v e r 1 0 0 0 b i l l i o n s i m u l a t e d c o l l i s i o n e v e n t s

  10. Test4Theory - LHC@home http://lhcathome.cern.ch/test4theory The ¡LHC@home ¡2.0 ¡project ¡Test4Theory ¡allows ¡users ¡to ¡par:cipate ¡in ¡running ¡ simula:ons ¡of ¡high-­‑energy ¡par:cle ¡physics ¡using ¡their ¡home ¡computers. The ¡results ¡are ¡submiAed ¡to ¡a ¡database ¡which ¡is ¡used ¡as ¡a ¡common ¡resource ¡by ¡both ¡ experimental ¡and ¡theore:cal ¡scien:sts ¡working ¡on ¡the ¡Large ¡Hadron ¡Collider ¡at ¡CERN. New July 4 th Users/Day 2012 New: ¡ Ci#zen ¡Cyberlab ¡(funds ¡from ¡EU) Develop ¡an ¡app ¡that ¡lets ¡ci8zen ¡scien8sts ¡ May June July Aug Sep learn ¡about, ¡interact ¡with, ¡and ¡op2mize ¡ high-­‑energy ¡physics ¡simula2ons , ¡by ¡ Why ? comparing ¡them ¡to ¡real ¡data 10 P. S k a n d s

  11. t h e b u i l d i n g b l o c k s o f L i f e T h e C a r b o n i n o u r b o d i e s T h e N i t ro g e n … we re m a d e i n s t a r s … T h e O x y g e n t h a t we b re a t h e All I know for sure: Nature is a Fantastic Work of Art So perhaps we are the eyes through Where did it come from? What is it? Where is it going? which the universe beholds itself ? It inspires us to think beyond ourselves From Quarks to Quasars 11 P . Skands

  12. Atomic Theory Stockholm, 1922 “ The present state of atomic theory is characterised by the fact that we not only believe the existence of atoms to be proved beyond a doubt, but also we even believe that we have an intimate knowledge of the constituents of the individual atoms ...” Niels Bohr (1885-1962) 12 P . Skands From Quarks to Quasars

  13. 1 Femtometer = 1fm = 10 -15 m ~ Size of a proton How ? Today, we even believe that we have an intimate knowledge of the constituents of nothing http://www.physics.adelaide.edu.au/theory/staff/leinweber/VisualQCD/Nobel From Quarks to Quasars 13 P . Skands Gluon action density: 2.4x2.4x3.6 fm, Supercomputer “Lattice simulation” from D. B. Leinweber, hep-lat/0004025

  14. High Energy Physics E = h f Long wavelength Low Energy The true nature of the strong nuclear force is revealed at distances below about 10 -15 m (= 10 -6 nm) Short wavelength More Energy To “see” something that small: need high energies (wavelength inversely proportional to energy): kick an electron with 1 billion Volts = 1 Giga-electron-Volt (GeV) “the Terascale” ! The energy of the Large Hadron Collider at CERN : 8 TeV In computer simulations, we try to recreate the collisions happening in the LHC in as much detail as mother nature. The clarity of our vision of the Terascale depends on their accuracy. You can help → LHC@home 2.0 14 P . Skands From Quarks to Quasars

  15. the real Accelerators 1932: Cockroft & Walton built a system that could fire protons, like bullets, into metal targets: p + LiF → Be, He, O, … Fermi Laboratory, Chicago, USA, Cavendish laboratory, UK, ca. 1932 ca. 2000 Modern van-de-Graaf Early van-de-Graaf, ca 1937 Early Van de Graaff Generator (Nobel 1951) “Transmutation of atomic nuclei by artificially accelerated atomic particles” 15 P . Skands From Quarks to Quasars

  16. Particle Accelerators The goal: E = mc 2 Accelerators ¡are ¡‘op8cal’ ¡systems, ¡with ¡ Light ¡  ¡charged ¡par:cles Lenses ¡  ¡magnets Wave ¡length ¡shortening ¡  ¡par:cle ¡accelera:on From Quarks to Quasars 16 P . Skands

  17. So what is “High” Energy ? Relative to combustion of 1 kg of octane molecules (gasoline) : 100m Waterfall : 0.000 025 Burning wood : 0.3 Burning sugar (metabolism) : 0.5 Burning ethanol or coal : 0.75 Burning Beryllium : 1.5 From Quarks to Quasars 17 P . Skands

  18. So what is “High” Energy ? Relative to combustion of 1 kg of octane molecules (gasoline) : 100m Waterfall : 0.000 025 Burning wood : 0.3 Burning sugar (metabolism) : 0.5 Burning ethanol or coal : 0.75 Burning Beryllium : 1.5 Uranium-235 Fission : 2 000 000 Deuterium-Tritium Fusion : 10 000 000 From Quarks to Quasars 18 P . Skands

  19. So what is “High” Energy ? Relative to combustion of 1 kg of octane molecules (gasoline) : 100m Waterfall : 0.000 025 Burning wood : 0.3 Burning sugar (metabolism) : 0.5 Burning ethanol or coal : 0.75 Burning Beryllium : 1.5 Uranium-235 Fission : 2 000 000 Deuterium-Tritium Fusion : 10 000 000 Matter-Antimatter Annihilation : 2 000 000 000 From Quarks to Quasars 19 P . Skands

  20. So what is “High” Energy ? Relative to combustion of 1 kg of octane molecules (gasoline) : 100m Waterfall : 0.000 025 Burning wood : 0.3 Burning sugar (metabolism) : 0.5 Burning ethanol or coal : 0.75 Burning Beryllium : 1.5 Uranium-235 Fission : 2 000 000 Deuterium-Tritium Fusion : 10 000 000 Matter-Antimatter Annihilation : 2 000 000 000 Tevatron collisions : 2 000 000 000 000 LHC collisions: 8 000 000 000 000 Still, Dan Brown exaggerated a bit in “Angels & Demons” … “If all of the antimatter ever produced at Fermilab had been collected, we would have a couple of nanogrammes …” Dave Vandermeulen, antimatter expert, Fermilab From Quarks to Quasars 20 P . Skands

  21. → Fundamental Science Fabiola Gianotti Spokeswoman of ATLAS July 4 th 2012: “Higgs-like” particle seen at CERN (+ over 500 other published physics papers from LHC so far)

  22. What is “Mass”? Consider a ‘field’ distributed evenly across the Universe, of uniform strength Suppose that different particles experience this ‘field’ as being more or less transparent To a photon (light), the field is completely “translucent” But an electron (or a proton), will interact with it Suppose that this field condenses around the particles which couple to it, causing an increased energy density around those particles. Looks like mass (E=mc 2 ). We call this field the “H” (or Higgs) Field If correct, it should be possible to create waves in the Higgs field itself (though that may require a lot of energy) From Quarks to Quasars 22 P . Skands

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