the oxford particle physics program · particle physics open day december 9 2019 (welcome!) the...
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Particle Physics Open Day
December 9 2019
(WELCOME!)
The Oxford Particle Physics
Program
Farrukh Azfar
Director of Graduate Studies for
Particle Physics(thanks Prof. Daniela Bortoletto& PP colleagues)
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Higgs as a new tool for
discovery
Identify the new
physics of dark
matter
Oxford is addressing the science drivers of particle physics
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The physics of
Neutrino mass
Understanding
cosmic
acceleration
Explore the
unknown: new
particles and
new interactions
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Outline
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• Why search for new physics ?
• Particle Physics Groups at Oxford
• ATLAS (Higgs, SUSY, Exotics, PDFs, Detectors, SM)
• LHC-b (CP Violation, Rare Decays, Detectors and more)
• Neutrinos (CP violation, Accelerator, Search for Majorana nus)
• LZ (Dark Matter)
• Mu3e (Lepton flavour violation)
• LSST (Dark Energy)
• Detector based projects
• Talk to us today – come and find us – examine opportunities!!
• For a list of projects look here (these get updated too)
http://www2.physics.ox.ac.uk/study-here/postgraduates/particle-
physics/thesis-topics
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The Standard Model
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The Standard Model
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• 1964 SM Theory
• 1984 LHC Design
• 1996 Start LHC construction
• 2009: first collisions
• 2012: Higgs Discovery
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Why look beyond the Standard Model?
Experimental Evidence
Non-baryonic dark matter
(~23%)
Inferred from gravitational effects
Rotational speed of galaxies
Orbital velocities of galaxies in
clusters
Gravitational lensing
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Dark Energy (~73%)
Accelerated Expansion of the
Universe
Neutrinos have mass and mix
Baryon asymmetry
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The Higgs boson• The discovery of the Higgs Boson raises many questions
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The Higgs boson• The discovery of the Higgs Boson raises many questions
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27km
Circumference
ATLAS
LHCb
The Large Hadron Collider – A Discovery Machine
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Operates above energy scale of SM:
13 TeV in 2015
Probes new physics
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ATLAS
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Barr, Bortoletto, Cooper–Sarkar, Gwenlan, Hays,
Huffman, Nickerson, Shipsey, Viehhauser,
Weidberg
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The Oxford ATLAS Group• Our goals:
– Shed light on new Higgs boson
• Measure its properties
• Improve our understanding of SM
– Discover new physics beyond SM
• Can we make & discover Dark Matter?
• Are there heavier Higgs bosons?
• Is nature supersymmetric?
• Look for more Exotics signatures
– Build key parts of next generation LHC
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Oxford Higgs Group• 3 academics: Bortoletto, Hays, Shipsey
• 2 Postdocs: Schopf (H→bb) and Artoni
(H→ZZ, H→𝜇𝜇 )
• 9 students: Ambroz, Foti, Karava, Miranova ,
Tosciri, Smith, Windischhofer Wolker, Zgubic
• Measured the Higgs coupling to b-quarks!
• More data will allow us to:
– Probe the Higgs coupling to the second
generation
– Test for physics beyond the SM (using for
example Effective Theory Interpretation)
– Search for new scalar particles
• Advanced analysis techniques (neural networks)
and major contributions to physics objects
• Strong collaborations with theorists
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Higgs in run 2 of the LHC• Oxford recent highlight contributions
• H→bb observed(expected) significance: 5.4(5.5)
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Higgs in run 2 of the LHC
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Until 6 years ago the
Yukawa coupling was
essentially a conjecture
no such term had ever
been seen in nature
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“SM & beyond” group• SM, Supersymmetry, Dark Matter,…
– 2 Academics: Barr, Gwenlan
– 2 Postdocs: Merlassino (3rd Gen SUSY and
triggers) and Nagai (Tracker ops and Strong
SUSY)
– 6 DPhil Students: Gallardo, O’Neill, Pownall,
Wuerzinger, Harris, Conroy
• Oxford students lead small teams & have many
world-first searches @LHC
– PDFs, W+jets, Squarks, Gluinos, Sleptons,
Higgsinos, Dark Matter, …
• Also contribute to ATLAS experiment
– e.g. triggering on events with Dark Matter
– reconstructing missing momentum
• Possible to combine with theory studies
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Supersymmetry
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• New symmetry of
space and time
(extends rotations
and boosts)
• Links fermions and
bosons
• Provides
“superpartner” to
each SM particle
• Lightest partner
Dark Matter
• Path to unification
& string theory
Dark
matter
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Supersymmetry example: Gluinos• Gluinos: spin-1/2 partners of gluons
• Masses expected ~ few TeV
• Produced in pairs & frequently
• Decay to (lots of) quarks + Dark Matter
(missing momentum)
1716 jet + missing momentum candidate
Aaron (DPhil student)leading the analysis
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SM example: Proton Structure (PDFs)
• PDFs uncertainties feed into ~all LHC
analyses, limiting measurements of Higgs
properties, reach of BSM searches, etc.
• LHC measurements provide strong
constraints on quark and gluon content
• Oxford Group lead the ATLAS analyses
using LHC data to determine PDFs
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Gavin (DPhil student) leading current analyses
A.Cooper-Sarkar,
academic (retired)
Gavin & Eimear (DPhil students) also leading final Run 2 W+jetsmeasurement
BLUE
includes
ATLAS
W+jets
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Oxford Higgs (SM) Exotics Group
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• Academic : Huffman
• 2 Fellows: Beresford, Frost
• Post-doc: Balunas
• 6 Students: Celli, Grundy, Paredes,
Stanislaus, Stankaityte, Veliscek
Search for new particles and effects
- Jet final states with b-quark pairs
- Higgs pairs decaying to b quark pairs
Novel techniques : Higgs tagging, NN
Extensive collaboration with theorists
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Instrumentation: Oxford Physics
Microstructure Detector Laboratory (OPMD)
• State-of-the art facility enhancing the development of new radiation sensors in Oxford and the UK
• Development of novel detectors for particle physics, photon science, and astrophysics
• Currently focusing on
– Depleted Monolithic Pixel Detectors for ATLAS
– Ultra Fast Silicon Detectors
– CCD for LSST Sharma
ShipseyBortoletto
Placket
Metodiev
Wood Weatherill
Mironova
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Barrel Silicon Tracker for ATLAS Upgrade ITk
• Use unique combination of facilities in Oxford
– Mechanical workshop, CNC & CMM etc.
– Autoclave (carbon fibre sandwich structures)
– Photofabrication
• Assembly of carbon fibre staves for ITk
• Design and testing of high speed electrical tapes
• Detector integration at CERN
• Engineering for barrel strip detector
Wastie
Viehhause
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Nickerson
Weidberg Jones
Yang
Li
(grad student)
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What to expect as a Student in ATLAS• Students work in small friendly teams
• Have a big impact
• Gain high visibility in ATLAS
• Take responsibility for projects or
detectors
• Long term stay at CERN
• Shifts at the detector
23ATLAS CONTROL ROOM START OF RUN 2
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LHCb
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• try
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The LHCb experiment
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• Several trillion B hadrons have
so far been produced at LHCb.
– to make precision measurements of CP violation
– to search for New Physics in rare B decays
• Critical for allowing this physics are particle identification and excellent vertex reconstruction.
– The RICH detectors were designed and build in Oxford
– VELO is a major Oxford activity
• LHCb is a general purpose experiment for
examining the “forward region” of the proton-proton
collisions
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CP violation!
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CP-violation in beauty hadrons
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In beauty system, the SM predicts sizable CP-violation.
And this is what we see!
Rate of decay and CP-conjugated process are clearly different !
Often, the SM predictions are precise.
The goal then is to make Correspondingly precise measurements.
Any Inconsistencies would indicate New Physics at work !
B0→K+π-
B0bar→K-π+Signal + residual
background
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• The apex of the CKM triangle is the world average measurement of their
value (from pre-LHC measurements of the triangle’s sides and angles). • Large error on — one of the key ingredients of a precise ρ,η determination!
• Oxford driven analysis has measured =74+5 -6 deg using B±→D0K± this
already equals the precision of previous measurements. Aiming to reduce
error to ± 3 deg
Precise CKM measurements
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LHCb offers fantastic opportunities for graduate students
• All graduate students are working on high-profile
analyses of LHC data.
• Graduate students participate fully in the running
of the experiment at CERN.
• BELOW: 3rd yr D.Phil. in the LHCb control
room
• The Oxford LHCb Oxford enjoys an great position in the international
collaboration.
• 3 Academics + 1 RSF (Harnew, Wilkinson, John, Malde)
• 10 D.Phil (Bijorn, Gruberg Cazon, Murphy, Pili. Pullen, Rollings Fischer,
Scantlebury-Smead , Mohammed, Smallwood, Suljk)
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The physics of neutrinos• T2K
• HyperK
• PROTODUNE
• DUNE
• SNO+
• MICROBooNE
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T2K Neutrino Oscillation experiment
• Measure disappearance of muon neutrinos to determine θ23 and Δm2
• Measure electron neutrino appearance
• Determine if neutrinos and antineutrinos behave the same. In fact, there is a
chance to find CP violation in THIS experiment.
• The group is also studying future neutrino experiments for CP violation discovery.
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T2K results so far
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T2K results so far
CP conserving values outside of 2σ region
for both hierarchies
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Upgrade SK to Hyper-K Start ~2022Total water mass of 0.99 Mt
Future = Liquid Argon in USA and Water Cherenkov in Japan
DUNE: planned long baseline
experiment. Start ~2022
4x10kT
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PROTODUNE
• 770 t LAr mass
• Exposed to H2 (DP)
and H4 (SP) test
beams at CERN (𝑒, K, 𝜇, 𝑝, 𝜋)
• Prototyping
production and
installation
• Validating the design
and long-term
operational stability
• Understanding,
calibration, dE/dx,
PID etc.
• PROTODUNE SP
2018 data taking
Daniela Bortoletto, LISHEP 2018,
Salvador36
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The Dark Universe
LZ
LSST
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• 7-tonne two-phase Xenon TPC (5.6t fiducial) to search for xenon
nuclei recoiling in response to collisions with dark matter particles.
• Oxford provides crucial TPC sensors/readout and simulations tools.
• Full exploitation requires significant simulation and analysis effort.
• Oxford group focused on analysis/simulation tasks.
Dark Matter Search with LZ (LUX-ZEPLIN)
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Oxford team:Hans Kraus
Amy Cottle
Andrew Stevens
Eilish Gibson
Matthew Tan
Niamh Fearon
Aiham Al Musalhi
LZ at the Sanford Underground Research Facility
Completion of installation and Commissioning in early 2020.
Plenty of D.Phil. opportunities with analysis of early data!
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Exploring the nature of dark energy
Oxford LSST Camera Test Stand
Particle Astro Synergy
PP: Azfar/Tseng/ShipseyAstro:Davies/Dunkley/Fender/Ferriera/Jarvis/Lintott/ Miller
Dark Energy LSST Meeting Oxford July, 2016
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Mu3e• Features
– Charged lepton flavor violating
– Via neutrino mixing
– Suppressed by (𝛥m𝜈2/ mW
2)2
– Expected BR(μ+→e+e-e+) < 10-50
• Importance
– Observable BR only from New
Physics
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Welcome to Oxford Particle Physics