The Standard Model of elementary particles

Large Hadron Collider at CERN and its experiments

Discovery of the Higgs boson

Particle Physics technologies find medical applications

Higgs particle discovery and measurements

- a breakthrough in physics

Elżbieta Richter-Wąs Institute of Physics, Jagiellonian University

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F. Englert P.Higgs

4-th of July 2012, ATLAS and CMS experiments at Large Hadron Collider at CERN announced observation of a new particle, consistent with predicted by so called „Higgs mechanism”.

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Nobel Prizes in Elementary Particle Physics

1957 – C. N. Yang, T. Lee 1965 – S. I. Tomonaga, J. Schwinger, R.P Feynman 1969 – M. Gell-Mann 1976 – B. Richter and S. Ting 1979 – S.L. Glashow, A. Salam, S. Weinberg 1980 – J. Cronin, V. Fitch 1984 – C. Rubbia, S. van der Meer 1988 – L. M. Lederman, M. Schwartz, J. Steinberger 1990 – J. Friedman, J. Kendall, R. Taylor 1992 - G. Charpak 1995 – M. Perl, F. Reines 1999 - G. tHooft, M. J. Veltman 2004 - D. J. Gross, H. D. Politzer, F. Wilczek 2008 – Y. Nambu, M. Kobayashi, T. Masakawa 2013 – F. Englert and P. Higgs

M. Gell-Mann

GREEN - theoretical BLUE - experimental

Detectors -> medical applications

1964: „Higgs mechanism” was born

2012: „Higgs particle” was discovered

Standard Model of elementary particles

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Qu

antu

m m

ech

anis

c

Force carriers

Matter particles (< 10 -16 cm)

Higgs particle Has a special role, it is neither a matter particle nor a force carrier.

Mass Spectrum of Elementary Particles

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Mass of the electrons is 25000 times smaller than mass of W, but if it was exactly zero there would be no atomic binding.

If the mass of the W boson was smaller, time of the combustion would be shorter and at lower temperature.

Mas

s (g

iga-

ele

ctro

n-v

olt

) 103

If the masses of elementary particles were different the Universe, as we know it, would not exist.

10-3

m = 0 Sun shield

Symmetry Broken symmetry Mass

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Hermann Weyl

(1918 /1929)

Symmetries in the system dictate interaction laws

Symmetries in the system dictate conservation laws

E. Noether (1918)

H. Weyl (1918, 1929) Spontaneously broken symmetry („hidden symmetry”) in the quantum system can generate mass.

J. Goldstone (1961), Y. Nambu (1960)

Discrete symmetry in art

Meta-stable conditions: Once the ball falls down, the symmetry of the system is „spontaneously broken” and system is in the stable conditions.

(*) hexagonal design (Chinese paper window support)

(*)

Vacuum Concept of the field Higgs mechanism

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Force lines of the magnetic field Introduced concept of field into description of magnetic interactions. Magnetic field has a source.

Higgs mechanism (1964): Quantum vacuum is not empty, is full of the „Higgs field”. This field has no structure nor sources. After „symmetry is spontaneously broken”, field is not „neutral” anymore and interaction of elementary particles with this field gives masses to the elementary particles . This mechanism predicted also the existence of a massive scalar particle, so called, „Higgs particle” which is the quantum fluctuation of the Higgs field.

Michael Faraday (1845)

In classical understanding vacuum = „empty space”, or state of „energy = 0”. In quantum mechanics vacuum is „full of life”. Just bubbling with creation and annihilation of matter particles. Symmetries dictate laws of interactions. Stable state of vacuum does not necessarily has an energy = zero.

„It doesn’t matter how beautiful your theory is, it doesn’t matter how smart you are. If it doesn’t agree with experiments, it’s wrong.”

R. Feynman

Theory has to be verified by experiment

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R. Feynman

There was no good idea how to observe the „Higgs field”. For several decades also discovery of the Higgs particle seemed to be beyond technological reach of experiments.

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How are we probing elementary particles, how are we exploring structure of Universe?

Virus

Radius of Earth

cm

Distance Earth-Sun

Galactica

Universe

Big-bang

LHC

Large distances events far apart in time

Short distances very large energies

LHC: Super microscop which creates Conditions as 10-12s after Big-Bang

CERN – European Laboratory for Particle Physics

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CERN was founded in 1954: („Science for peace”)

ATLAS Collaboration

38 państw

Mont Blanc

Jezioro Genewskie CERN

Today: 21 member states, more than 11000 users

CERN’s primary mission is SCIENCE. Main area of research is particle physics – study of the fundamental constituents of matter and the forces acting between them.

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LHC (Large Hadron Collider)

27 km długości 100m pod ziemią

Mont Blanc

Lake Geneva

27 km circuit 100m underground

ATLAS

CMS

LHC

One of the most ambitious projects in Science

• Składniki protonu

Proton-proton collisions

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Proton bunch

Interacting quarks

Colliding protons

Production and decay of a new particle

Such event in 1/1012 of interactions

Protonów/pęczek

pęczków/wiązkę

Energia wiązki

Each proton is moving close to the speed of light and carry energy of a fly. It turns around the ring with a frequency of 1100 times/second. Beam cross-section at collision point: 16mm (4 times smaller than diameter on human hair). Each beam has energy of TGV train (200m) moving with the speed of 155km/hour (360M Jule).

Proton-Proton 1380 bunches/beam Protons/beam 1.7 1011

Beam energy 4 TeV ( = 4 106 MeV)

We accelerate two beams

ATLAS detector: 42m length, 22 m diameter; 3000 km of cables outputting electronic signal; more than 108 readout channels; precision in positioning of some elements is about microns.

ATLAS detector and collaboration

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Atlas Collaboration: More than 3000 physicists, engineers and technicians, including more than 1000 PhD students; 178 institutions from 38 countries; Polish groups: IFJ-PAN, AGH and Institute of Physics UJ

ATLAS detector

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ATLAS

Analysis of the registered event: In 3 years each experiment registered on the disc more than 5 109 of interesting events = 20 PB (1015 bytes) of data. If written on the CD discs, it would make a tower 20 km in high.

How did we observe Higgs particle?

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~450 registered Higgs particle decays look similarly. It was complex, one detectable Higgs particle produced every 1012 collisions.

Probability < 10-13 that it is not a statistical fluctuation of the background. Analysed are multi-dimensional distributions.

Mass = 125.4 ( ± 0.3% ) GeV

Quantum state JPC = 0+

Interacts with elementary particles

Interaction strenght is proportional to their mass.

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Measuring properties of the Higgs particle

All experimental observations so far are consistent with the predictions of the Higgs mechanism!

The next step will be to confirm that the Higgs particle interacts with itself as predicted.

Large Hadron Collider is operating again…

… maybe we will be able to understand why there is such asymmetry between matter and anti-matter in the Universe? Will we ever understand what is a dark-matter and dark-energy which are 95% of the Universe … Is the value of the vacuum of the Higgs field associated with the cosmological constant in Einstein equation…?

Event recorded 03.06.2015 at a collision energy of 13 TeV ( x2 more than so far)

We are starting now the route to UNKNOWN …!

More than 1000 papers published 2010-2015 by 4 LHC experiments.

G. Charpak (Nobel Prize in Physics, 1992) For invention of multi-wire chamber detectors (1968); Made possible to increase data collection speed by factor 1000 and improve significantly spatial resolution. Widely used technology in Particle Physics Exp.; Found its applications in medicine and biology.

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Particle physics technologies find medical applications

G. Charpak, 1924 - 2010

(Randomly picked article )

Pressurized xenon wire-chamber gamma camera , allowed for using short-lived radionuclei 178Ta, which greatly reduced radiation dosimetry and allowed for brief duration of data acquisition. The wire chamber camera is starting to be utilized in number of clinical areas.

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Large Hadron Collider is operating again… Particle physics technologies find medical applications

Accelerating particles beams:

~30 000 accelerators worldwide

~17 000 used for medical applications

LHC CERN has been collaborating to the design and testing of two last generation dual facilities, designed to provide proton and carbon ion beams: CNAO (Pavia) and MedAustron (Austria). On site, CERN transforms Low Energy Ion Ring (LEIR) into biomedical facility. One of the facilities at CERN generates custom radioisotopes for clinical research.

Frontier machines like LHC push particle detectors beyond state-of-art to achieve needed resolution and speed, fuelling new developments in medical imaging. One example are LYSO crystals used for modern PET and PET/CT scanners. Faster and more sensitive detectors allow for in-vivo monitoring in real time during therapeutic irradiation: AX-PET, Medpix, Crystal Clear, EVISION, … 20

Particle physics technologies find medical applications

Digital imaging -> medical diagnostics eg. PET (Positron Emission Tomography)

Detecting particles

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Particle physics technologies find medical applications

Data analysis techniques in the Grid-based distributed computing systems Unprecedented is amount of data processed by LHC experiments

Epidemiology Genetics

MammoGrid

Monte Carlo simulation tools ( Geant4, Fluka) developed for particle physics

300 000 volumes of ATLAS detector Used to model sources and geometries which have moving parts. Allows to simulate interactions of all particles type (electrons, positrons, photons, etc.) with composite matter

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Discovery of the Higgs boson is a turning point.

After 50-years last building block of Standard Model has fallen into place and opened the door to something completely new.

„What we know is a droplet, what we don’t know is an Ocean” Isaac Newton (1663-1727).

Research is a long and endless path.

It is very difficult to predict what would be the effect of todays discoveries in fundamental science 50 years from now.

However, tools and technology developed today in one discipline, continuously find applications and provide inspirations elsewhere, often in unexpected places.

SPARE SLIDES

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• SPARE SLIDES

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(Almost) Final Run-I Coupling Results

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1968 1974 1995

1968 1974 1977

1956 1962 2000

1897 1937 1976

1979

1923

1983

1983 2012

1995 1979 1974 1968

When elementary particles have been discovered?

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Many possible extensions to probe

Evolution of the Universe

LHC probes this energy range, about 10-12 s

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