Olivier Mattelaer University of Illinois at Urbana Champaign

Transcription

1 MadWeight 5 MEM with ISR correction Olivier Mattelaer University of Illinois at Urbana Champaign P. Artoisenet, V. Lemaitre, F. Maltoni, OM: JHEP1012:068 P.Artoisent, OM: In preparation J.Alwall, A. Freytas, OM: PRD83: Matrix Element Workshop May

2 Outline MadWeight5 Basic idea of the phase space integration Improvement/ new features of MadWeight5 MEM with ISR correction Motivation Method Higgs mass measurement 2

3 MADWEIGHT 5 3

4 Matrix Element Re-weighting How to evaluate those weights? P(p vis )= 1 d dx 1 dx 2 M (p) 2 W (p, p vis ) 4

5 Matrix Element Re-weighting How to evaluate those weights? P(p vis )= 1 d dx 1 dx 2 M (p) 2 W (p, p vis ) Fit from MC tuned to the detector resolution 4

6 Matrix Element Re-weighting How to evaluate those weights? P(p vis )= 1 d dx 1 dx 2 M (p) 2 W (p, p vis ) Fit from MC tuned to the detector resolution Use of matrix-element generator: MadGraph 4

7 Matrix Element Re-weighting How to evaluate those weights? P(p vis )= 1 d dx 1 dx 2 M (p) 2 W (p, p vis ) Fit from MC tuned to the detector resolution Use of matrix-element generator: MadGraph Need a specific integrator: MadWeight 4

8 Matrix Element Re-weighting How to evaluate those weights? P(p vis )= 1 d dx 1 dx 2 M (p) 2 W (p, p vis ) Fit from MC tuned to the detector resolution Use of matrix-element generator: MadGraph 5 Need a specific integrator: MadWeight 5 4

9 MADWEIGHT p a p b First Example: di-leptonic top quark pair degrees of freedom 16 t m 3 m 4 t W + m 1 W m 2 b ν µ ν µ µ + µ b p 4 p 5 p 1 p 2 p 6 p 3 2: pdf 3 x 6: final states -4: energy-momentum conservation peaks 16 4: Breit-Wigner 3 x 4: visible particles 5

10 MADWEIGHT p a First Example: di-leptonic top quark pair t m 3 W + m 1 b ν µ µ + p 4 p 5 p 1 degrees of freedom 16 peaks 16 p b m 4 t W m 2 ν µ µ b p 2 p 6 p 3 All peaks aligned 6

11 MADWEIGHT p a First Example: di-leptonic top quark pair t m 3 W + m 1 b ν µ µ + p 4 p 5 p 1 degrees of freedom 16 peaks 16 p b d = 4 i=1 m 4 d 3 p i (2 ) 3 2E i t W m 2 6 i=5 ν µ µ b p 2 p 6 p 3 All peaks aligned d 3 p i 4 (2 ) 3 dx 1 dx 2 p a + p b 2E i j p j 6

12 MADWEIGHT p a First Example: di-leptonic top quark pair t m 3 W + m 1 b ν µ µ + p 4 p 5 p 1 degrees of freedom 16 peaks 16 p b d = 4 i=1 m 4 d 3 p i (2 ) 3 2E i t W m 2 6 i=5 ν µ µ b p 2 p 6 p 3 All peaks aligned d 3 p i 4 (2 ) 3 dx 1 dx 2 p a + p b 2E i j p j Pass to d = 4 d i d i d p i 4 dm 2 j J i=1 j=1 6

13 MADWEIGHT Second Example: semi-leptonic top quark pair b p 4 p a p b t m 3 m 4 t W + m 1 W m 2 ν µ u ν µ d µ + µ p 5 p5 p 1 p 2 p 6 degrees of freedom 16 peaks 19 b p 3 7

14 MADWEIGHT Second Example: semi-leptonic top quark pair b p 4 p a p b t m 3 m 4 t W + m 1 W m 2 ν µ u ν µ d µ + µ p 5 p5 p 1 p 2 p 6 degrees of freedom 16 peaks 19 3 peaks unaligned b p 3 Multi-channel 7

15 MadWeight q 1... p i, θ 1,φ 1 fully hadronic / leptonic process q 2 p j, θ 2,φ 2 q 1 Class A... p νx,p νy,p νz i 1 W production q 2 q 1 Class B... θ, φ p p νx,p νy,p νz semi-leptonic top quark pair i 2 i 1 q 2 Class C q 1 q 2... i 1 i 3 i 4 i 2 p ν1 x,p ν1 y,p ν1 z p ν2 x,p ν2 y,p ν2 z Fully leptonic top quark pair Class D 8

16 MadWeight... ŝ y i 3 i 1 i 2 p ν1 x,p ν1 y,p ν1 z p ν2 x,p ν2 y,p ν2 z Higss production decaying in W Class E... i 3 i 4 i 2 i 1 p ν1 x,p ν1 y,p ν1 z p ν2 x,p ν2 y,p ν2 z W+ W- production Class F 9

17 MadWeight... ŝ y i 3 i 1 i 2 p ν1 x,p ν1 y,p ν1 z p ν2 x,p ν2 y,p ν2 z Higss production decaying in W Class E... i 3 i 4 i 2 i 1 p ν1 x,p ν1 y,p ν1 z p ν2 x,p ν2 y,p ν2 z W+ W- production Class F Lot of possibility to have p 1 more complex process m i 1 p ν m i 1 p m i m 2 i 1 p 2 +1 W +1 Z m i 3 m i 2 m i 1 p ν θν φ ν m i 2 m i 1 p ν θ ν

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23 MadWeight5 Improvement Use MG5 idea of Subprocess merging MW4 SubProcesses g g > t t~ MW5 SubProcesses p p > t t~ u u~ > t t~ u~ u > t t~ d d~ > t t~ d~ d > t t~ 5 Integrals to perform 1 Integral to perform 11

24 MadWeight5 Improvement Narrow width approximation Reduce the dimension of the Phase-Space Be careful: The matrix-element AND the transfer function should be flat enough. This reduces the discrimination power. In MW5, all particles with a width lower than a given value will be integrated in this approximation. default value: 0.1 So by default only for the Higgs 12

25 MadWeight5 Improvement Treatment of permutations b p 4 t m 1 u ν µ p 5 p5 p a m 3 W + d µ + p 1 p b m 4 t W m 2 ν µ µ b p 2 p 6 p 3 MW4: one integral per permutation MW5: Monte-Carlo over the permutation process tf permutation Sum/MonteCarlo tt semi leptonic delta tt semi leptonic gauss 24 2 tt di leptonic gauss w+ j j delta tth (semi lept) gauss

26 MadWeight5 Improvement Better choices of PS parameterization Pre-defined grid for the transfer functions Smarter refine function between channel of integration New interface (scriptable edition of the cards) New cluster support Creation of the directory on the flight Submission by packet / support of multicore New output format (xml) Full support of BSM physics (via UFO/ALOHA) ISR support 14

27 Speed Benchmark Comparison process perm MW4 MW5 tt semi lept 24 1h16 71s tt fully lept 2 46s 14s tth semi lept 720 > 2 days 43min tth semi lept 48 > 3h 11min tth fully lept 24 >1h 1min h> w+ w- > 1lept 2 59s <5s h> w+ w- > 2lept 1 8s <5s z b b 24 39m 18s zh 24 43m <5s running on 1core of a Intel core i7 2.3Ghz 15

28 MEM with radiation 16

29 MEM with radiation p p rad }{{} p 0 1 p a 2 pb pin X p p 0 1 p a 2 p b p rad }{{} p in X Those radiations are important ttj is 50% at LHC The topics pop outs in talks a couple of times 3 Main idea (both were mention yesterday) Transfer boost MLM NLO 17

30 MLM NLO My point of view Having one more jets at the matrix element level is roughly 10 times slower. number of permutations (assignment jet-parton) complexity of the integrand dimension of the phase-space The radiation problem still occurs (at least for the inclusive sample) Speed of the virtual Only valid for one additional jet 18

31 Radiations p p rad }{{} p 0 1 p a 2 pb pin X p p 0 1 p a 2 p b p rad }{{} p in X ISR Main Effect is to induce a transverse boost. Different PDF FSR Need to be parameterize in the TF Having a one parton evolving in two jets TF Reasonable with MC over permutation 19

32 Radiations p p rad }{{} p 0 1 p a 2 pb pin X p p 0 1 p a 2 p b p rad }{{} p in X ISR Main Effect is to induce a transverse boost. Different PDF Here I will focus on ISR FSR Need to be parameterize in the TF Having a one parton evolving in two jets TF Reasonable with MC over permutation 19

33 Choices of variables Higgs production top pair production 2 g g h w- w+ 2 u u~ g t t~ w+ w- b b~ 6 vm~ mu- 4 vm 5 mu+ ve mu- e+ 3 vm~ Higgs Mass s-channel No FSR top Mass presence of FSR 20

34 Initial State Radiation 2 g g h w- w+ 6 vm~ mu- 4 vm 5 Study the ISR on Higgs production at LHC (14 TeV) at parton level (no hadronization) mu

35 Initial State Radiation 2 g g h w- w+ 6 vm~ mu- 4 vm 5 mu+ Study the ISR on Higgs production at LHC (14 TeV) at parton level (no hadronization) No ISR No Bias 1 L L max No ISR in event generation events with ISR: cut p T 40 GeV cut p T 6 GeV Boost correction only Boost correction with Sudakov reweighting input mass m h GeV 21

36 Initial State Radiation 2 g g h w- w+ 6 vm~ mu- 4 vm 5 mu+ Study the ISR on Higgs production at LHC (14 TeV) at parton level (no hadronization) Large Veto Large bias 1 L L max No ISR in event generation events with ISR: cut p T 40 GeV cut p T 6 GeV Boost correction only Boost correction with Sudakov reweighting m h GeV 21

37 Initial State Radiation 2 1 g g L L max h w- w+ vm~ mu- mu+ 6 4 vm 5 3 Study the ISR on Higgs production at LHC (14 TeV) at parton level (no hadronization) smaller veto smaller bias but larger statistical uncertainties 1.0 No ISR in event generation events with ISR: cut p T 40 GeV cut p T 6 GeV Boost correction only Boost correction with Sudakov reweighting m h GeV 21

38 Initial State Radiation 2 1 g g L L max h w- w+ 6 vm~ mu- 4 vm 5 mu+ 3 Study the ISR on Higgs production at LHC (14 TeV) at parton level (no hadronization) Use the ISR to boost the momenta small bias/error No ISR in event generation events with ISR: cut p T 40 GeV cut p T 6 GeV Boost correction only Boost correction with Sudakov reweighting m h GeV 21

39 Initial State Radiation 2 1 g g L L max 1.0 h w- w+ No ISR in event generation vm~ mu- mu+ 6 4 vm 5 3 Study the ISR on Higgs production at LHC (14 TeV) at parton level (no hadronization) Add the Sudakov Factor No significative bias z p in,z p in,z + p rad,z, events with ISR: cut p T 40 GeV cut p T 6 GeV Boost correction only Boost correction with Sudakov reweighting m h GeV 21

40 Initial State Radiation Parton Level for top pair production L L max No ISR in event generation events with ISR, cut p T 40 GeV Boost correction only Boost correction with Sudakov reweighting m t GeV Less sensitivity 22

41 Initial State Radiation 2 g g h w- w+ 6 vm~ mu- 4 vm 5 Study the ISR on Higgs production at LHC (14 TeV) at detector level (simulation includes pile-up) mu+ 1 3 W ISR (p T,p vis T )= { L L max No ISR in event generation events with ISR, cut p T 40 GeV [ 1 2π(a2 +a 3 a 5 ) e (p T p vis T a 1) 2 /(2a 2 2 ) + a 3 e (p T p vis T a 4) 2 /(2a 2)] 5, 1 π b2 p T e (log(p T) b 1 ) 2 /(2b 2 2 ) Boost only for p vis T >p0 T, for p vis T <p0 T, Veto Boost correction only Boost correction with ISR integr m h GeV 23

42 Initial State Radiation 2 1 g g h w- W ISR (p T,p vis T )= { L L max w+ No ISR in event generation vm~ events with ISR, cut p T 40 GeV mu- vm 5 mu Study the ISR on Higgs production at LHC (14 TeV) at detector level (simulation includes pile-up) Introduce ISR transfer functions [ 1 2π(a2 +a 3 a 5 ) e (p T p vis T a 1) 2 /(2a 2 2 ) + a 3 e (p T p vis T a 4) 2 /(2a 2)] 5, 1 π b2 p T e (log(p T) b 1 ) 2 /(2b 2 2 ) Boost only for p vis T >p0 T, for p vis T <p0 T, Veto Boost correction only Boost correction with ISR integr m h GeV 23

43 Initial State Radiation Reconstructed Level for top pair production L L max No ISR in event generation events with ISR, cut p T 40 GeV events with ISR, cut p T 20 GeV Boost correction only 0.2 Boost correction with ISR integr m t GeV 24

44 Conclusion MadWeight5 will be released soon with nicer interface / cluster support with huge speed improvement with ISR support Radiation problem MLM/NLO slower method Transverse boost is working Need transfer function on the boost 25