The exploration of strongly interacting matter Andr Mischk e - PowerPoint PPT Presentation

The exploration of strongly interacting matter André Mischk e Utrecht University Inaugural presentation – Physics and Engineering Section, Academia Europaea – 3 September 2017

Outline • About myself • Structure of matter • The quark-gluon plasma • The measuring apparatus • Heavy-quarks as a sensitive probe • Exciting future André Mischke (Utrecht University) 2

A few words about myself • Associate Professor of Physics at Utrecht University, the Netherlands • PhD at Goethe-University of Frankfurt, Germany • Studies in Physics and Mathematics at Philipps- University of Marburg, Germany • Married, one child • Founding chair, Young Academy of Europe • My specific research area: dynamical properties of the quark-gluon plasma • Deputy team leader, Dutch research group in the ALICE Collaboration André Mischke (Utrecht University) 3

What is matter? Visible universe (for us) Constituents of the universe André Mischke (Utrecht University) 4

Structure of (“visible”) matter Particle physics: search for the smallest (fundamental) constituents • Atoms • Atomic nuclei • Protons and neutrons • Quarks and gluons André Mischke (Utrecht University) 5

The Standard Model • Basis of particle physics - Elementary particles - Fundamental interactions - Generation of mass: Higgs Mechanism (Nobel Prize 2013) • Gravity is not described by the Standard Model • Still open questions - Strong interaction has a couple of properties that are not well understood. André Mischke (Utrecht University) 6

Quark confinement • Strong interaction Protons and described by Quantum- gluon neutrons are Chromodynamics colour neutral states. • Quarks quark - have colour charge - are confined (hadrons) α s ( r ) V ( r ) = − 4 + kr • Asymptotic freedom 3 r k = 1 GeV/fm How can we liberate quarks? Create a Quark-Gluon Plasma André Mischke (Utrecht University) 7

Different phases of matter Pressure + Heat à Quark Gluon Plasma André Mischke (Utrecht University) 8

Phase diagram Water Subatomic matter André Mischke (Utrecht University) 9

The Quark-Gluon Plasma (QGP) Phase transition to QGP Heat and pressure T ≈ 10 12 K ≈ 10 5 x sun’s core • Novel state of matter: quarks and gluons are liberated (deconfinement) • The hottest man-made matter • Evolution of the early universe - QGP may still exist in neutron stars sun André Mischke (Utrecht University) 10

Evolution of the Universe Quark-hadron phase transition 11

The Quark-Gluon Plasma (QGP) Phase transition to QGP Heat and pressure T ≈ 10 12 K ≈ 10 5 x sun’s core • Produce and study the QGP in the laboratory - sufficient large reaction volume - high density and temperature à Collisions of heavy atomic nuclei (lead or gold) • Large Hadron Collider at CERN: exploration of the plasma properties André Mischke (Utrecht University) 12

• Most powerful particle accelerator in the world • Working at cutting edge of science, technology and computing 9 km 100 m 13 13

• 1232 dipole magnets • Two counter-rotating beams • Operation with superfluid helium at 1.9K (~120 tons) • 8 Tesla bending field • 14 TeV proton-proton and 27 km circumference 5.5 TeV lead-lead collisions 14

The ALICE detector A L arge I on C ollider E xperiment lead beam lead beam Size : 16 x 26 meters Weight : 10.000 tons 18 Sub-detectors Dipole magnet B=0.5 T André Mischke (Utrecht University) 15

bang

Proton-proton collision at 13 TeV Tracks of produced particles detected in the measuring apparatus André Mischke (Utrecht University) 17

Lead-lead collision at 5.02 TeV “Run-2 data taking” from 2015-2018 Charm quark à D meson bound state André Mischke (Utrecht University) 18

Probing strongly interacting matter Collision of Reference • Heavy quarks heavy atomic nuclei measurement - are produced in pairs heavy quark - two types: charm and beauty proton proton Quark-Gluon - well-calibrated probes Plasma heavy quark • Interaction with the plasma → energy loss after collision André Mischke (Utrecht University) 19

D measurements in lead-lead collisions 2 Nuclear modification factor Nuclear modification factor 0 + + Average D , D , D* ALICE ALICE 1.8 Pb-Pb, = 2.76 TeV, | |<0.5 s y NN Yield AA ( p T ) 0-10% 1.6 R AA ( p T ) = with pp -extrap. reference p T N bin AA Yield pp ( p T ) 30-50% 1.4 p-Pb, = 5.02 TeV, -0.96 < <0.04 s y NN cms 1.2 ß No plasma 1 0.8 0.6 0.4 0.2 ß With plasma 0 0 5 10 15 20 25 30 35 40 (GeV/ ) Transverse momentum p c T ALI − PUB − 99591 • In lead-lead collisions: strong suppression of the yield when compared to “simple scaling” from proton-proton interaction • Still have to learn from theory about medium properties André Mischke (Utrecht University) 20

Summary Quark-Gluon-Plasma is a new form of strongly interacting matter Evolution of the universe Quark-Gluon Atomic nuclei Plasma ? Big Bang Particle accelerator: collision of heavy atomic nuclei • What are the properties of the interaction between quarks and gluons in the plasma phase? One of the central • Outlook: quantitative understanding of the questions in the energy loss and dissipation in the plasma NuPECC LRP report Andre Mischke (Utrecht) 21

Thank you André Mischke (Utrecht University) 22 22