Communicating the science behind particle physics a challenge taken by Netzwerk Teilchenwelt. Michael Kobel KIT Seminar Karlsruhe,

Transcription

1 Communicating the science behind particle physics a challenge taken by Netzwerk Teilchenwelt Michael Kobel KIT Seminar Karlsruhe,

2 1. Netzwerk Teilchenwelt 2. Written Materials 3. Activities 4. More Michael Kobel, TU Dresden 2

3 Communicating Particle Physics Strength and Chances Fascination of fundamental questions Fascinating notions (Big Bang, Antimatter, Dark Matter, ) Fascinating experiments Fundamental research as cultural and intellectual gain Challenges Large number of new terms Many new concepts and perceptions Many answers to never-posed questions Relation to everyday world to be established Michael Kobel, TU Dresden 3

4 Netzwerk Teilchenwelt Multi-level program for high school students, aged teachers/trainers at schools, school labs, science centers events per year 26 research labs + CERN central organization: TU Dresden Two Core actions 1. Events and activities on all levels analyzing real (even own) research data 2. Developing written materials for teaching and science communication

5 2. Material development I. Accompanying netzwerk activities II. Supporting material for facilitators and teachers Particle Profiles Background information and worksheets Freely available as Printed versions Download at Web pages for students Hosted on Largest German Physics Portal for schools: Relaunch of particle physics section 2014

6 III. To appear soon particle physics for schools, comprising > 300 pages of texts, exercises and work sheets Establishing a standardized terminology 4 sections Concept of the Standard Model Research methods Cosmic rays Stand alone topics

7 How to explain something unknown Example soccer (wikipedia) Law 1: The Field of Play Law 2: The Ball Law 3: The Number of Players i.e. you do not start with the number of players, but with the aims and rules! you do not mention each single player so why do we always start with this: when explaining the Standard Model?

8 What is the Standard Model, after all? A theoretical framework of Symmetries SU(3) C x SU(2) I x U(1) Y Based on charges Ordering particles Requiring interactions So, the SM a theory of interations, (=rules) after all And: the particles (=players) cannot even be predicted!

9 Concept: Interaction Reduction of Physics = Force + Transfomation + Production + Annihilation All processes can be described by 4 fundamental interactions Force is just one aspect of interaction Hangabtriebskraft, Wasserkraft, Gasdruck, Radiowellen, Benzinmotor Luftreibung, Radioaktiver Zerfall Brennen der Sonne 4 Fundamental Interactions Michael Kobel, TU Dresden 9

10 Tell a Story: Start with 2 best known interactions Electromagnetic (e.g. Atoms) Gravitation (O 2 by Earth) What keeps the protons (and neutrons) in the nucleus together against electric repulsion? introduce: strong interaction Michael Kobel, TU Dresden 10

11 The 4th fundamental interaction Electromagnetic Gravitation Strong interaction What transforms neutrons introduce: weak interaction and protons in one another? Michael Kobel, TU Dresden 11

12 Overview of potential energies (similarities and differences) electromagnetic Gravitation weak interaction strong interaction Michael Kobel, TU Dresden 12

13 Synopsis on different scales Electromagnetic potential is invariant under scale variations -> infinite range Weak and strong interaction have characteristic length all behave like 1/r for small enough distances Quantitative description with Charges Strength parameter α Char. Lengths λ w = 0,002 fm and (ħcα S /k) = 0,2 fm

14 Comparison of Forces F = E pot for e + e - (strong: qq) Particle physics Us Nuclear physics Michael Kobel, TU Dresden 14

15 Conclusions Ranges are different For small distances F~1/r 2 Sequence of strength Cannot be defined for forces due to F(r) Can be defined only for interactions: α! All interaction strengths similar, except *extremely* weak gravitation Interaction Gravitation electromagnetic Range infinite infinite strong weak Michael Kobel, TU Dresden 15

16 Why are forces ~ 1/r²? Classical Physics: field lines Density of field lines ~ field strength ~ force 1/r² is consequence of 3-dim space! 1/r n-1 wohl be the force law for n-dim space Michael Kobel, TU Dresden 16

17 Many Further discussion issues Unification of interactions maybe possible for gravity with large extra dimensions -> steeper decrease at tiny distances Nuclear kovalent binding is not fundamental (like molecular binding) and only possible in a very narrow range Michael Kobel, TU Dresden 17

18 Why are all the interactions so similar in their structure? There are a number of possibilities: The first is the limited imagination of physicists: When we see a new phenomenon, we try to fit it in the framework we already have until we have made enough experiments we don t know that it doesn t work It s because physicists have only been able to think of the same damn thing, over and over again. Another possibility is that it is the same damn thing over and over again that Nature has only one way of doing things, and She repeats her story from time to time. A third possibility is that things look similar because they are aspects of the same thing some larger picture underneath Richard. P. Feynman, The strange theory of light and matter Princeton University Press, 1985 Die seltsame Theorie des Lichts und der Materie Piper Taschenbuch, 9,95

19 Charges: Basis of the Standardmodel Expressed for Scientists: Charges generate local gauge symmetries of the Standard Model Particles come in multiplet representations of the gauge group Symmetries require gauge fields and interactions Charge conservation follows from Gauge Symmetry The BEH mechanism breaks the electroweak symmetry and creates masses for the weak gauge bosons For the public communication: For each interaction (except gravity) there is a corresponding charge Charges give a characteristic ordering principle for particles Interactions are mediated by messenger particles Charge conservation determines allowed processes The BEHiggs field is a infinite sea of weak charge and created finite range of weak interaction by screening its field

20 Superconductor Analogy Superconductor: Cooper-pair field, freely movable ee-pairs, screening magnetic fields Eweak vacuum: BEH field, freely moving weak charges, screening weak fields Source: beamline/26/1/26-1- dixon.pdf In a superconductor, the range of the magnetic force (photons) is tiny: λ~20 nm The photons get an effective mass of 1/ λ ~ 10 ev In the BEH-Field, the range of W-Bosons is λ~ 0.000,000,002 nm (its screening is 10,000,000,000 more effective!) and m W =1/ λ ~ 100 GeV Cooper-pair coherence length relation ξ < λ corresponds to 1/m H < 1/m W Our universe is a Type-II superconductor for weak charges 20

21 Charge -> interaction + messengers Each interaction (= force or transformation) is mediated by messengers messengers can only be emitted/absorbed, if corresonding charge is present Charges can be numbers or vectors Couplings e, g W, g S absorbed from the beginning in strength parameters α, α W,α S! Interaction Messenger particles Charge of matter particles Strong Gluons g Strong Color -Charge vector Weak Electromagnetic Weakons (W +,W -,Z) Photons γ Weak Isospin -Charge I = + 1/2 1/2 Electric Charge number q = -1, + ⅔, -⅓, Gravitation Gravitons? Probably! Mass??? No! Michael Kobel, TU Dresden 21

22 Matter Particle Multipletts Particles are ordered/characterized according to their three charges Experimentally (this is no SM prediction!) one finds doublets wrt weak interaction tripletts wrt strong interaction singuletts wrt electromagnetic interaction Transformations are only allowed within same multiplet (for charge eigenstates, mixing into mass eigenstates omitted) Michael Kobel, TU Dresden 22

23 Gauge bosons transform within multiplet A rotation (gauge symmetry!) of a quark multiplet has same effect as emission or absorption of a gluon Michael Kobel, TU Dresden 23

24 Ordering scheme: Analogy to periodic system Same Charges <-> same features (e.g. lepton universality) Which slots are filled by particles in nature cannot be predicted in SM! Pattern repeats 2x for larger masses (reason unknown!) Michael Kobel, TU Dresden 24

25 The SM just gives the ordering cupboard! Filling of the possible drawers cannot be predicted C C Other matter particle multiplets would have been possible! particle e -- e - e 0 e + e ++ I but are not observed nature picks fundamental representation

26 Adding Charges (Example Proton) Electric charge number Weak charge number Strong color charge vector Michael Kobel, TU Dresden 26

27 Charge conservation (e.g. weak charge I:=I 3W ) Neglecting P-Violation, since only left-chiral components matter: K-electron capture in atoms p +½ -½ +½ -½ W + -½ +½ -½ +½ e - First detection of (anti-)neutrinos at nuclear power plants +½ p n -½ +½ p n -½ W + -½ +½ -½ +½ β + und β - transformations of nuclei n ν e ν e e + +½ p n -½ -½ n p +½ W + e + ν e +½ -½ e - +½ -½ Conservation of weak charge requires presence of neutrinos (Lepton number concept not needed, charge conservation does it) p e - W - W - n ν e ν e e + W - ν e

28 Spiral curriculum concept for textbook Michael Kobel, TU Dresden 28

29 Example: Feynman diagrams in spiral curriculum Compton-Scattering 1st level: x-y diagram, visualisation in space (as in detector) 2nd level: classical x-t diagram charge conservation in initial and final state 3rd level: Feynman diagram Charge conservation at each time Fundamental vertices Quantum mechanical behaviour Michael Kobel, TU Dresden 29

30 Summary New Teaching Material Lots of Dos and Dont s Conyev the real SM findings Establishing a standardized terminology Charges as powerful new principles Global view of interactions Spiral curriculum Finalized last year, in layout, will be printed and distributed to teachers Training for teachers planned

31 3. Netzwerk Teilchenwelt Events and Activities: four levels Research Theses -Workshops Project weeks at CERN Research Projects CERN Research Participation Training and Workshops at CERN Active contributions Proliferation of experiences School projects Qualification Active contributions Running own projects Masterclass participation (Particle Physics, Astroparticlephysics, International Masterclasses) Basic Participation in introductory events Students Teachers Folie 31

32 Particle physics Masterclasses 1 day in schools, also school labs, exhibitions (~120 p.a.) facilitators = PhD students agenda: introductory talk (standard model, accelerators, detectors) measurement with LHC data using event displays (ATLAS, CMS, ALICE, LHCb) Recently extended to astroparticle experiments (Auger, ICECUBE) Possibly also for teachers Covering whole Germany

33 Concept for basic masterclass format High school students and teachers are scientists for one day as close as possible to current research experience how scientists explore nature own hands-on activities hear forget // see remember // do understand Get insight into scientific research process use the same tools and methods like scientists theory experiment direct contact with (young) physicists stimultate students interest in physics raise fascination for particle physics understand fundamental research as fundamental knowledge for society Not primarily: knowledge transfer (1 day is too short)

34 Example: Analysis with real LHC data ATLAS CMS ALICE W path (W + /W - + H WW) Z path (Z, Z, ) J/Ψ data quality W,Z,H analysis Strange Particles Modification Factor R AA Rich spectrum of tasks Check data quality Event displays, identify particles Histograms (Mass, angles) Draw conclusions Freely accessible for education purposes Continuously following research progress 2012: simulated Higgs events 2013: real Higgs candidates LHCb Charm lifetime TOTEM (to come) pp diffraction pattern

35 CMS WZH measurement 3D event display Students characterize W, Z, and Higgs candidates Create mass plot of standard model particles that decay into 2 leptons, plus Higgs Ratios W+/W-, e/µ 3000 events with misfits, surprises, interpretation Michael Kobel, TU Dresden 36

36 ALICE : Looking for strange particles Search for strange particles from their V0-decays Visual identification of V0s from their decay pattern Invariant mass calculation First part : visual analysis of ~ 15 events per group Merging of results Second part: Calculation of numbers of Ks, Λ, anti Λ from invariant mass distributions (fit gaussian/polynomial to peak/background; subtract background) for different centrality regions in lead-lead collisions Concepts conveyed : invariant mass; centrality of PbPb collisions; background results : observe strangeness enhancement in Pb-Pb collisions comparing with pp collisions Use ROOT-based simplified ALICE event display K 0 s π + π Λ π p + anti Λ p - π + Strangeness enhancement: the particle yield normalised by the number of participating nucleons in the collision N part, and divided by the yield in proton-proton collisions N part Michael Kobel, TU Dresden 38

37 Astroparticle Projects Scintillator experimenta CosMo and Kamiokanne loan to schools (after teachers training) Variety of measurements: angular distribution coincidence muon lifetime (2 signals within 20 μs) study particle shower Cloud chamber sets Web experiments Auger data New portal: at DESY 2016 International Cosmic Day DAQ board Photomultiplier Scintillator Michael Kobel, TU Dresden 39

38 Workshops + Project Weeks at CERN Students 60 students in two annual workshops (3 days) 10 students in project weeks own research projects, e.g. Medipix detector, CLOUD, ATLAS trigger system, lifetime B-Meson, LHC beam steering, ASACUSA, track finding, Teachers 40 teachers in two annual workshops (5 days) big motivation for activities very effective training for teachers in modern physics Michael Kobel, TU Dresden 40

39 Research Projects 2015 : Untersuchungen der Fragmentationen und Entstehungsprodukte von Antiproton-Titankern-Kollisionen sowie Annihilationen in Photoplatten und Untersuchungen der Teilchenproduktionen und -bahnen bei der Injektion von Antiprotonen im AD research projects for 3-10 months often part of final school examinations work on own measurements, possible continuation at project week tutors: PhD students/ physicists at universities and teachers Several awards (2-4 per year!) Jugend forscht Dr. Hans Riegel-Fachpreis Von Ardenne Physikpreis /jugendliche/projekt-,%20fachund%20forschungsarbeiten/ Michael Kobel, TU Dresden 41

40 Student Alumni > 100 participants of CERN Workshops own activities yearly meeting evaluation in July 2014: Consolidating decision to study physics: NTW helped me a lot in deciding to study physics. I learned how exciting physics can be, outside of school. 2/3 studying physics Michael Kobel, TU Dresden

41 4. More Masterclasses Netzwerk Teilchenwelt Local Masterclasses in DE ~ 170 Masterclasses / year Scientist school Multi-level programme International Masterclasses Worldwide, 45 countries ~ 260 Masterclasses / year High school students lab Video conference with CERN or Fermilab Michael Kobel, TU Dresden

42 International Masterclasses 2016 Organized by IPPOG (International Particle Physics Outreach Group: independent group of outreach representatives from countries at CERN) countries involved Coord.: QuarkNet / TU Dresden 42 institutes 48 Masterclasses 35 CMS 13 ATLAS 22 video conf. with Fermilab 170 institutes 246 Masterclasses 134 ATLAS 56 CMS 32 LHCb 24 ALICE 54 video conf. with CERN

43 How *you* can contribute Netzwerk Teilchenwelt facilitator (Vermittler) Hold a Masterclass in a school or a cosmic ray project Supervisor of student s research project commitment is acknowledged with certificates (and remuneration) International Masterclass tutor at your institute Moderator at CERN Michael Kobel, TU Dresden 46

44 Training for facilitators PhD students, Diploma and Master students facilitate Masterclasses and Cosmic Projects in schools 2,5 days workshops exchange of experience training in didactics + science communication improve your soft skills Michael Kobel, TU Dresden

45 Benefits for all stakeholders Students Inspired and fascinated by doing own measurements/research Meeting scientists (role model) Direct contact to research labs Alumni organisation Teachers Training Exchange with colleagues and scientists Encouragement to include particle physics in school Material for lessons

46 Benefits for all stakeholders Facilitators See the relevance of their work to society Soft skills: science communication, didactics Training provided (2.5 d workshop) Broader view: (particle astro, theory experiment) Research labs Increased public appreciation and visibility Contact to future students Support (experiments, material, organisation, )

47 Network Community Scientists: > 100 (young) scientists activities experiments scientists perspectives Students: 4000 involved in activities in qualification level or higher Staff: 6 staff management coordination communication Teachers: 400 involved in activities qualification level of higher Michael Kobel Alumni: 85 registered 40 at first meeting in 2013 studying physics (and other) bring in own activities

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