Monte Carlo Event Generators for High Energy Particle Physics Event Simulation
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Introduction to Parton-Shower Event Generators
SLAC-PUB 16160 Introduction to parton-shower event generators Stefan H¨oche1 1 SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA Abstract: This lecture discusses the physics implemented by Monte Carlo event genera- tors for hadron colliders. It details the construction of parton showers and the matching of parton showers to fixed-order calculations at higher orders in per- turbative QCD. It also discusses approaches to merge calculations for a varying number of jets, the interface to the underlying event and hadronization. 1 Introduction Hadron colliders are discovery machines. The fact that proton beams can be accelerated to higher kinetic energy than electron beams favors hadron colliders over lepton colliders when it comes to setting the record collision energy. But it comes at a cost: Because of the composite nature of the beam particles, the event structure at hadron colliders is significantly more complex than at lepton colliders, and the description of full final states necessitates involved multi-particle calculations. The high-dimensional phase space leaves Monte-Carlo integration as the only viable option. Over the past three decades, this led to the introduction and development of multi-purpose Monte-Carlo event generators for hadron collider physics [1, 2]. This lecture series discusses some basic aspects in the construction of these computer programs. 1.1 Stating the problem The search for new theories of nature which explain the existence of dark matter and dark energy is the arXiv:1411.4085v2 [hep-ph] 18 Jun 2015 focus of interest of high-energy particle physics today. One possible discovery mode is the creation of dark matter candidates at ground-based collider experiments like the Large Hadron Collider (LHC). -
Monte Carlo Event Generators
Durham University Monte Carlo Event Generators Lecture 1: Basic Principles of Event Generation Peter Richardson IPPP, Durham University CTEQ School July 06 1 • So the title I was given for these lectures was ‘Event Generator Basics’ • However after talking to some of you yesterday evening I realised it should probably be called ‘Why I Shouldn’t Just Run PYTHIA’ CTEQ School July 06 2 Plan • Lecture 1: Introduction – Basic principles of event generation – Monte Carlo integration techniques – Matrix Elements • Lecture 2: Parton Showers – Parton Shower Approach – Recent advances, CKKW and MC@NLO • Lecture 3: Hadronization and Underlying Event – Hadronization Models – Underlying Event Modelling CTEQ School July 06 3 Plan • I will concentrate on hadron collisions. • There are many things I will not have time to cover – Heavy Ion physics – B Production – BSM Physics – Diffractive Physics • I will concentrate on the basic aspects of Monte Carlo simulations which are essential for the Tevatron and LHC. CTEQ School July 06 4 Plan • However I will try and present the recent progress in a number of areas which are important for the Tevatron and LHC – Matching of matrix elements and parton showers • Traditional Matching Techniques • CKKW approach • MC@NLO – Other recent progress • While I will talk about the physics modelling in the different programs I won’t talk about the technical details of running them. CTEQ School July 06 5 Other Lectures and Information • Unfortunately there are no good books or review papers on Event Generator physics. • However -
Nuwro - Neutrino MC Event Generator
NuWro - neutrino MC event generator Tomasz Golan 28.04.2017, UW HEP Seminar Outline Neutrino source νe Detector ′ α 1. Motivation να νµ ντ 2. NuWro event generator 3. Final State Interactions 3500 MB data Total 3000 EL on carbon np-nh 2500 EL on hydrogen Irreducible background 2000 Other backgrounds 1500 4. MB NCEL data analysis No. of events 1000 500 0 0 100 200 300 400 500 600 700 Reconstructed kinetic energy (MeV) Tomasz Golan NuWro @ HEP UW 2 / 61 Introduction Basic properties of neutrinos ■ 1 Three generations 2 -spin, no electric charge, small mass Introduction of fermions H Neutrino properties (extremely hard to detect) I II III PMNS matrix Probability of oscillation u c t γ Neutrino oscillation ■ Measurement idea Interactions with elementary particles Example: T2K BOSONS QUARKS s g Energy reconstruction → electroweak theory (Standard Model) d b MC generators ■ ν νµ ν 0 NuWro Interactions with nucleons e τ Z Final state interactions → form factors e µ τ ± MB NCEL analysis → parton distribution functions LEPTONS W Backup slides ■ Interactions with nuclei → nuclear effects ■ The neutrino flavor state is a superposition of the mass states: |ναi = i Uαi |νii νe The neutrino producedP in α state να νβ νµ ντ can be measured in β state. The phenomenon is called neutrino oscillation. Tomasz Golan NuWro @ HEP UW 4 / 61 Pontecorvo-Maki-Nakagawa-Sakata matrix The PMNS matrix defines the mass mixing in the lepton sector: −iδ 1 0 0 c13 0 s13e c12 s12 0 U = 0 c23 s23 0 1 0 −s12 c12 0 iδ 0 −s23 c23 −s13e 0 c13 0 0 1 cij = cos θij sij = sin θij θij - mixing angels δ - CP phase factor Measurements: 2 ■ Solar, reactor and accelerator: sin (2θ12) = 0.846 ± 0.021 2 ■ Atmospheric: sin (2θ23) > 0.92 2 ■ Reactor: sin (2θ13) = 0.093 ± 0.008 δ can be measured if and only if all mixing angles are nonzero. -
PDF) Submittals Are Preferred) and Information Particle and Astroparticle Physics As Well As Accelerator Physics
CERNNovember/December 2019 cerncourier.com COURIERReporting on international high-energy physics WELCOME CERN Courier – digital edition Welcome to the digital edition of the November/December 2019 issue of CERN Courier. The Extremely Large Telescope, adorning the cover of this issue, is due to EXTREMELY record first light in 2025 and will outperform existing telescopes by orders of magnitude. It is one of several large instruments to look forward to in the decade ahead, which will also see the start of high-luminosity LHC operations. LARGE TELESCOPE As the 2020s gets under way, the Courier will be reviewing the LHC’s 10-year physics programme so far, as well as charting progress in other domains. In the meantime, enjoy news of KATRIN’s first limit on the neutrino mass (p7), a summary of the recently published European strategy briefing book (p8), the genesis of a hadron-therapy centre in Southeast Europe (p9), and dispatches from the most interesting recent conferences (pp19—23). CLIC’s status and future (p41), the abstract world of gauge–gravity duality (p44), France’s particle-physics origins (p37) and CERN’s open days (p32) are other highlights from this last issue of the decade. Enjoy! To sign up to the new-issue alert, please visit: http://comms.iop.org/k/iop/cerncourier To subscribe to the magazine, please visit: https://cerncourier.com/p/about-cern-courier KATRIN weighs in on neutrinos Maldacena on the gauge–gravity dual FPGAs that speak your language EDITOR: MATTHEW CHALMERS, CERN DIGITAL EDITION CREATED BY IOP PUBLISHING CCNovDec19_Cover_v1.indd 1 29/10/2019 15:41 CERNCOURIER www. -
Event Generators
Event Generators XI SERC School on Experimental High-Energy Physics NISER Bhubaneswar, November 07-27, 2017 Event Generators Session 1 Introduction IntroductionIntroduction Typical high energy event (p+p collision) and possible processes: Long Island, New York, USA Typical highTypical energy high event energy ( eventp+p collision)(p+p collision) and and possible possible processes: processes: M. H. Seymour and M. Marx, arXiv:1304.6677 [hep-ph] 1. Hard process 1. Hard process 2. Parton shower 2. Parton shower 3. Hadronization 3. Hadronization 4. Underlying event 4. Underlying event 5. Unstable particle decays 5. Unstable particle decays If we could create a model that rightly incorporates most physics processes and rightly predicts the physics results… Helps Increase the physics understanding of the high energy collisions2 and data results obtained 2 2 Event Generators – In General Long Island, New York, USA ü Computer programs to generate physics events, as realistic as could be using a wide range of physics processes. ü Use Monte Carlo techniques to select all relevant variables according to the desired probability distributions and to ensure randomness in final events. ü Give access to various physics observables ü Different from theoretical calculations which mostly is restricted to one particular physics observable ü The output of event generators could be used to check the behavior of detectors – how particles traverse the detector and what physics processes they undergo -- simulated in programs such as GEANT. 3 Need of Event Generators Long Island, New York, USA ü Interpret the observed phenomena in data in terms of a more fundamental underlying theory; Give physics predictions for experimental data analysis. -
Isolated Electrons and Muons in Events with Missing Transverse Momentum at HERA
Physics Letters B 561 (2003) 241–257 www.elsevier.com/locate/npe Isolated electrons and muons in events with missing transverse momentum at HERA H1 Collaboration V. Andreev x,B.Andrieuaa, T. Anthonis d,A.Astvatsatourovai,A.Babaevw,J.Bährai, P. Baranov x, E. Barrelet ab, W. Bartel j, S. Baumgartner aj, J. Becker ak, M. Beckingham u, A. Beglarian ah,O.Behnkem,A.Belousovx,Ch.Bergera,T.Berndtn,J.C.Bizotz, J. Böhme j, V. Boudry aa,J.Braciniky, W. Braunschweig a,V.Brissonz, H.-B. Bröker b, D.P. Brown j,D.Brunckop,F.W.Büsserk,A.Bunyatyanl,ah,A.Burrager, G. Buschhorn y, L. Bystritskaya w, A.J. Campbell j,S.Carona, F. Cassol-Brunner v, V. Chekelian y, D. Clarke e,C.Collardd,J.G.Contrerasg,1, Y.R. Coppens c, J.A. Coughlan e, M.-C. Cousinou v,B.E.Coxu,G.Cozzikai, J. Cvach ac, J.B. Dainton r, W.D. Dau o, K. Daum ag,2, M. Davidsson t, B. Delcourt z, N. Delerue v, R. Demirchyan ah, A. De Roeck j,3,E.A.DeWolfd,C.Diaconuv, J. Dingfelder m,P.Dixons, V. Dodonov l, J.D. Dowell c,A.Dubaky,C.Duprelb,G.Eckerlinj,D.Ecksteinai, V. Efremenko w, S. Egli af,R.Eichleraf,F.Eiselem,M.Ellerbrockm,E.Elsenj, M. Erdmann j,4,5, W. Erdmann aj, P.J.W. Faulkner c,L.Favartd,A.Fedotovw,R.Felstj, J. Ferencei j, S. Ferron aa,M.Fleischerj, P. Fleischmann j,Y.H.Flemingc,G.Fluckej, G. Flügge b, A. Fomenko x,I.Forestiak, J. -
Jet Structures in Higgs and New Physics Searches
Jet structures in Higgs and New Physics searches Gavin P. Salam LPTHE, UPMC Paris 6 & CNRS Focus Week on QCD in connection with BSM study at LHC IPMU, Tokyo, 10 November 2009 Part based on work with Jon Butterworth, Adam Davison (UCL), John Ellis (CERN), Tilman Plehn (Heidelberg), Are Raklev (Stockholm) Mathieu Rubin (LPTHE) and Michael Spannowsky (Oregon) LHC searches for hadronically-decaying new particles are challenging: ◮ Huge QCD backgrounds ◮ Limited mass resolution (detector & QCD effects) ◮ Complications like combinatorics, e.g. too many jets ◮ Especially true for EW-scale new particles New strategy emerging in past 2 years: boosted particle searches ◮ Heavy particles reveal themselves as jet substructure ◮ E.g. top/W/H from decay of high mass particle ◮ Or directly Higgs (etc.) production at high pt This talk ◮ 70% on one major search channel: pp HV with H bb¯ → → Butterworth, Davison, Rubin & GPS ’09 ◮ 30% on other applications of these ideas many groups, including Butterworth, Ellis, Raklev & GPS ’09; Plehn, GPS & Spannowsky ’09 LHC searches for hadronically-decaying new particles are challenging: ◮ Huge QCD backgrounds ◮ Limited mass resolution (detector & QCD effects) ◮ Complications like combinatorics, e.g. too many jets ◮ Especially true for EW-scale new particles New strategy emerging in past 2 years: boosted particle searches ◮ Heavy particles reveal themselves as jet substructure ◮ E.g. top/W/H from decay of high mass particle ◮ Or directly Higgs (etc.) production at high pt This talk ◮ 70% on one major search channel: pp HV with H bb¯ → → Butterworth, Davison, Rubin & GPS ’09 ◮ 30% on other applications of these ideas many groups, including Butterworth, Ellis, Raklev & GPS ’09; Plehn, GPS & Spannowsky ’09 LHC searches for hadronically-decaying new particles are challenging: ◮ Huge QCD backgrounds ◮ Limited mass resolution (detector & QCD effects) ◮ Complications like combinatorics, e.g. -
QCD at the Large Hadron Collider
QCD at the Large Hadron Collider Jon Butterworth SLAC Summer Institute SLAC August 2018 Outline • Total cross section and parton densities • The soft stuff • Jet production • Jet substructure • Heavy Flavour production • Measuring the coupling • Quark and gluon matter • Future prospects Aug 2018 JMB: QCD@LHC SSI 2 Outline • Total cross section and parton densities • The soft stuff • Jet production • Jet substructure • Heavy Flavour production • Measuring the coupling • Quark and gluon matter • Future prospects Aug 2018 JMB: QCD@LHC SSI 3 Modelling the Underlying Underlying the Event Modelling Aug 2018 JMB: QCD@LHC SSI 4 Modelling the Underlying Underlying the Event Modelling Aug 2018 JMB: QCD@LHC SSI 5 To the TeV scale and beyond… Pic from Sherpa/F.Krauss Aug 2018 JMB: QCD@LHC SSI 6 Measuring multiparton scattering ATLAS: arXiv:1301.6872 Aug 2018 JMB: QCD@LHC SSI 7 Measuring multiparton scattering CMS: arXiv:1312.5729 Aug 2018 JMB: QCD@LHC SSI 8 So what about jets then? Aug 2018 JMB: QCD@LHC SSI 9 ‘Hard’ QCD • When quarks and gluons make a break for it… Jets! Aug 2018 JMB: QCD@LHC SSI 10 ‘Hard’ QCD • When quarks and gluons make a break for it… Jets! Aug 2018 JMB: QCD@LHC SSI 11 ‘Hard’ QCD • When quarks and gluons make a break for it… Jets! Aug 2018 JMB: QCD@LHC SSI 12 What is a Jet? • Protons are made up of quarks and gluons. • Quarks and gluons are coloured and confined – we only ever see hadrons. • A jet of hadrons is the signature of a quark or gluon in the final state. -
A-Level Physics Transition Work Summer 2021
A-level Physics Transition Work Summer 2021 Welcome to A-level Physics! Congratulations on choosing the best A-level subject! The purpose of this work is to revise key concepts from GCSE so that you are as ready as possible for A-level Physics in September. Please complete this work on separate sheets of paper and bring it with you to your first Physics lesson in September. We expect to see all three tasks attempted and self-marked. You should expect to find some of the tasks hard. If you are stuck with any of this work, please feel free to contact Mr. Smith ([email protected]) for a hint. There are three tasks. You should spend 1½ to 2 hours on each one. Complete as many of the questions as you can in this time. If you don’t get to the end of the questions, that is fine as long as you have made the effort. Task 1 Energy Task 2 Electric circuits Task 3 Resultant force All the answers are in the back, so you can check your work yourself. (If you think you have spotted a mistake in the answers, please let us know using the email address above!) Other resources to help you prepare… GCSE revision guides - use these to revise key knowledge. The first topics you will study are electricity (AQA P2) and forces and motion (AQA P5), so these are the best sections to focus on. Buy the CGP books ‘Head Start to A-level Physics’ (tinyurl.com/ycboqamn) and ‘Essential Maths Skills for A-level Physics’ (tinyurl.com/y9grnrag). -
Search for Higgs Boson Decays to Beyond-The-Standard-Model Light Bosons in Four-Lepton Events√ with the ATLAS Detector at S = 13 Tev
EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH (CERN) JHEP 06 (2018) 166 CERN-EP-2017-293 DOI: 10.1007/JHEP06(2018)166 25th July 2018 Search for Higgs boson decays to beyond-the-Standard-Model light bosons in four-lepton eventsp with the ATLAS detector at s = 13 TeV The ATLAS Collaboration A search is conducted for a beyond-the-Standard-Model boson using events where a Higgs boson with mass 125 GeV decays to four leptons (` = e or µ). This decay is presumed to occur via an intermediate state which contains one or two on-shell, promptly decaying bosons: H ! ZX/XX ! 4`, where X is a new vector boson Zd or pseudoscalar a with mass between 1 and 60 GeV. The search uses pp collision data collected with the ATLAS detectorp at the LHC with an integrated luminosity of 36.1 fb−1 at a centre-of-mass energy s = 13 TeV. No significant excess of events above Standard Model background predictions is observed; therefore, upper limits at 95% confidence level are set on model-independent fiducial cross- sections, and on the Higgs boson decay branching ratios to vector and pseudoscalar bosons in two benchmark models. arXiv:1802.03388v2 [hep-ex] 24 Jul 2018 © 2018 CERN for the benefit of the ATLAS Collaboration. Reproduction of this article or parts of it is allowed as specified in the CC-BY-4.0 license. Contents 1 Introduction 2 2 Benchmark models3 2.1 Vector-boson model4 2.2 Pseudoscalar-boson model5 3 ATLAS detector 6 4 Event reconstruction7 4.1 Trigger and event preselection7 4.2 Lepton reconstruction7 4.3 Definition of invariant-mass kinematic variables8 4.4 -
Diss. Eth No. 26674 SEARCHES for SUPERSYMMETRY in the FULLY
diss. eth no. 26674 SEARCHES FOR SUPERSYMMETRY IN THE FULLY HADRONIC AND HIGGS TO DIPHOTON FINAL STATES A thesis submitted to attain the degree of doctor of sciences of eth zurich (Dr. sc. ETH Zurich) presented by myriam schönenberger M.Sc.Physics, ETH Zurich born on 9 April 1990 citizen of Mosnang SG CERN-THESIS-2020-090 06/03/2020 accepted on the recommendation of Prof. Dr. R. Wallny, examiner Prof. Dr. G. Dissertori, co-examiner 2020 Searches for physics beyond the Standard Model (SM) are a main focus of the physics program at the Large Hadron Collider at CERN. I present in this thesis two searches for supersymmetry (SUSY), using data collected with the Compact Muon Solenoid detector. The first search is a broad range search for SUSY in the tails of the stransverse mass distribution MT2. Data collected in the year 2016 corresponding to an integrated luminosity of 35.9 fb−1 are used to obtain data driven estimates of the Z νν, lost ! leptons and QCD multijet backgrounds. No sign of SUSY has been found. Upper limits on the production cross section of simplified models of SUSY are set. Gluino masses up to 2 TeV are excluded for a massless lightest supersymmetric particle (LSP). Squark masses up to 1 TeV(1:6 TeV) for one (four) light squark type(s) for a massless LSP are excluded. The second search explores strong and electroweak SUSY production through the final state of a Higgs boson decaying to a photon pair analyzing 77.5 fb−1 of integrated luminosity collected in 2016 and 2017. -
Introduction to Monte Carlo for Particle Physics Study
Introduction to Monte Carlo for Particle Physics Study N. SRIMANOBHAS (Dept. of Physics, Faculty of Science, Chulalongkorn University) 1st CERN School Thailand October 4, 2010 1 วันจันทร์ที่ 4 ตุลาคม 2010 Credit where credit is due I collected (stole) most of my slide from Tomasz Wlodek (Monte Carlo methods in HEP) Concezio Bozzi (Monte Carlo simulation in Particle Physics) P. Richardson CERN-Fermilab school 2009 Geant4 school 2009 2 วันจันทร์ที่ 4 ตุลาคม 2010 Monte Carlo (MC) [From Tomasz Wlodek slides] General idea is “Instread of performing long complex calculations, perform large number of experiments using random number generation and see what happens” Problem: Calculate the area of this shape Any idea? 3 วันจันทร์ที่ 4 ตุลาคม 2010 10x10 40x40 Area = (# Hits)/(# Total) x total area 4 วันจันทร์ที่ 4 ตุลาคม 2010 History Method formally developed by John Neumann during the World War II, but already known before. It was used to study radiation shielding and distance that neutrons would likely travel through material. Von Neumann chose the codename "Monte Carlo". The name is a reference to the Monte Carlo Casino in Monaco where Ulam's uncle would borrow money to gamble. 5 วันจันทร์ที่ 4 ตุลาคม 2010 Why Monte Carlo? Monte Carlo assumes the system is described by probability density functions (PDF) which can be modeled. It does not need to write down and solve equation analytically/numerically. PDF comes from - Data driven - Theory driven - Data + Theory fitting 6 วันจันทร์ที่ 4 ตุลาคม 2010 Particle physics uses MC for (1) Detector design and optimization Complicate and huge detector Very expensive (2) Simulation of particle interactions with detector’s material (3) Physics analysis New predicted physics: SUSY, UED, ..