Excited State Spectroscopy & QCD Hadron spectroscopy 2 - - PowerPoint PPT Presentation

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Excited State Spectroscopy & QCD Hadron spectroscopy 2 - - PowerPoint PPT Presentation

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Excited State Spectroscopy & QCD Hadron spectroscopy 2 Determination of hadron spectrum of QCD a central goal in NP Several experiments worldwide USQCD All-Hands Meeting | May 1, 2015 Spectrum - light meson experiments 3 USQCD

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SLIDE 1

Excited State Spectroscopy & QCD

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SLIDE 2

USQCD All-Hand’s Meeting | May 1, 2015

Hadron spectroscopy

2

  • Determination of hadron spectrum of QCD a central goal in NP
  • Several experiments worldwide
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SLIDE 3

USQCD All-Hand’s Meeting | May 1, 2015

Spectrum - light meson experiments

3

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USQCD All-Hand’s Meeting | May 1, 2015

Nuclear Physics & Jefferson Lab

4

  • JLab finishing a $335M upgrade
  • Doubled beam energy
  • Added new Hall D (GlueX)
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SLIDE 5

USQCD All-Hand’s Meeting | May 1, 2015

  • Most hadrons are resonances
  • E.g., πN πN
  • Formally defined as a pole in a partial-wave scattering amplitude
  • Different channels should have same pole location
  • Pole structure gives decay information
  • Can we predict hadron properties from first principles?

Resonances

5

Re(E) Im(E)

E (MeV)

tl(s) ∼ R s0 − s + . . .

s0 = sr

0 + si

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SLIDE 6

USQCD All-Hand’s Meeting | May 1, 2015

Isospin=1 ππ P-wave

6 expand angular dependence in partial waves PARTIAL WAVE AMPLITUDE elastic inelastic

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USQCD All-Hand’s Meeting | May 1, 2015

Isospin=1 ππ P-wave

7 RESONANT PHASE SHIFT

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SLIDE 8

USQCD All-Hand’s Meeting | May 1, 2015

ρ resonance

8

30 60 90 120 150 180 800 850 900 950 1000 1050

PDG

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SLIDE 9

USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering amplitudes

9 D-WAVE πK→πK AMPLITUDE

0.4 0.8 1.2 1.6 2.0 2.4 0.26 0.28 0.30

LASS D-WAVE

LASS, NPB296 493

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SLIDE 10

USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering amplitudes

9 D-WAVE πK→πK AMPLITUDE

0.4 0.8 1.2 1.6 2.0 2.4 0.26 0.28 0.30

LASS D-WAVE

LASS, NPB296 493

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SLIDE 11

USQCD All-Hand’s Meeting | May 1, 2015

S-wave πK/ηK more complicated

10

LASS, NPB296 493

0.2 0.4 0.6 0.8 1 1.2 0.18 0.20 0.22 0.24 0.26 30 60 90 120 150 180 0.18 0.20 0.22 0.24 0.26

S-WAVE πK→πK AMPLITUDE LASS S-WAVE

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USQCD All-Hand’s Meeting | May 1, 2015

Major objective

11

  • Compute decays (branching fractions) of exotic mesons:

EXOTIC JPC

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SLIDE 13

USQCD All-Hand’s Meeting | May 1, 2015

Major objective - exotic meson decays

12

  • LQCD suggests existence of exotic mesons
  • Expt. determination requires measurement in many

decay channels

  • Present LQCD calculations missing this info
  • Objective is to compute them ahead of expt.

➡ Guide expt. analysis

JLab expt. beam has started

EXOTIC JPC

ρπ b1π f1π η0π . . .

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SLIDE 14

USQCD All-Hand’s Meeting | May 1, 2015

What pion mass?

13

  • Getting to the physical pion mass not the most pressing concern here
  • Need to establish feasibility of techniques for resonances
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SLIDE 15

USQCD All-Hand’s Meeting | May 1, 2015

What pion mass?

13

  • Getting to the physical pion mass not the most pressing concern here
  • Need to establish feasibility of techniques for resonances
  • Hard to do with physical kinematics

e.g. Some of the simple low-lying resonances: the number of open channels is too large to start here

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SLIDE 16

USQCD All-Hand’s Meeting | May 1, 2015

What pion mass?

13

  • Getting to the physical pion mass not the most pressing concern here
  • Need to establish feasibility of techniques for resonances
  • Hard to do with physical kinematics

e.g. Some of the simple low-lying resonances: the number of open channels is too large to start here

  • Development of three-body formalism required

HANSEN & SHARPE - MUCH PROGRESS

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USQCD All-Hand’s Meeting | May 1, 2015

LQCD workflow

14

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USQCD All-Hand’s Meeting | May 1, 2015

LQCD workflow

14

Generate the configurations

! Leadership level ! 60K cores, 10’s TF-yr

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USQCD All-Hand’s Meeting | May 1, 2015

LQCD workflow

14

Generate the configurations

! Leadership level ! 60K cores, 10’s TF-yr

Analyze

100K copies 4 Kepler GPUs

+

t=0 t=T

Propagators

Q[U]−1

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SLIDE 20

USQCD All-Hand’s Meeting | May 1, 2015

LQCD workflow

14

Generate the configurations

! Leadership level ! 60K cores, 10’s TF-yr

Analyze

100K copies 4 Kepler GPUs

+

t=0 t=T

Propagators

Q[U]−1 Now also AMG!

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SLIDE 21

USQCD All-Hand’s Meeting | May 1, 2015

LQCD workflow

14

Generate the configurations

! Leadership level ! 60K cores, 10’s TF-yr

Analyze

100K copies 4 Kepler GPUs

+

t=0 t=T

Propagators

Q[U]−1

t=0 t=T

Contract

  • 8 cores, CPUs

Correlators

100K – 1M copies Now also AMG!

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SLIDE 22

USQCD All-Hand’s Meeting | May 1, 2015

LQCD workflow

14

Generate the configurations

! Leadership level ! 60K cores, 10’s TF-yr

Analyze

100K copies 4 Kepler GPUs

+

t=0 t=T

Propagators

Q[U]−1

t=0 t=T

Contract

  • 8 cores, CPUs

Correlators

100K – 1M copies Now also AMG!

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SLIDE 23

USQCD All-Hand’s Meeting | May 1, 2015

LQCD workflow

14

Generate the configurations

! Leadership level ! 60K cores, 10’s TF-yr

Analyze

100K copies 4 Kepler GPUs

+

t=0 t=T

Propagators

Q[U]−1

t=0 t=T

Contract

  • 8 cores, CPUs

Correlators

100K – 1M copies

Few big jobs Few big files Many small jobs Many big files I/O movement

Now also AMG!

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SLIDE 24

USQCD All-Hand’s Meeting | May 1, 2015

LQCD workflow

15

Generate the configurations

! Leadership level ! 60K cores, 10’s TF-yr

Analyze

100K copies 4 Kepler GPUs

+

t=0 t=T

Propagators

Q[U]−1

t=0 t=T

Contract

  • 8 cores, CPUs

Correlators

100K – 1M copies

~25% > 5% ~75%

New analysis cost

Leadership level Throughput mode

Now also AMG!

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USQCD All-Hand’s Meeting | May 1, 2015

Scattering in a finite cubic volume

16

  • Expect a discrete spectrum in a finite periodic volume

elastic scattering phase-shift

Discrete energies in a finite-volume e.g. free particle quantized momentum

  • For an interacting theory

known function

Discrete values

  • f the phase-shift

LÜSCHER …

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USQCD All-Hand’s Meeting | May 1, 2015

Scattering in a finite cubic volume

17

0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 10.0 15.0 20.0 25.0 30.0 35.0

CUBIC BOX SPECTRUM P-WAVE PHASE SHIFT

0.4 0.6 0.8 1.0 1.2 50 100 150

  • Experimental ππ I=1 P-wave scattering amplitude
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USQCD All-Hand’s Meeting | May 1, 2015

ππ P-wave phase-shift

18

30 60 90 120 150 180 0.14 0.15 0.16 0.17 0.18 0.19

PRD87 034505 (2013)

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USQCD All-Hand’s Meeting | May 1, 2015

ππ P-wave phase-shift

18

30 60 90 120 150 180 0.14 0.15 0.16 0.17 0.18 0.19

PRD87 034505 (2013)

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USQCD All-Hand’s Meeting | May 1, 2015

ρ resonance

19

30 60 90 120 150 180 800 850 900 950 1000 1050

PDG

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USQCD All-Hand’s Meeting | May 1, 2015

Coupled-channel scattering

20

  • Finite-volume formalism recently derived (multiple methods)

scattering matrix phase space known functions

  • However, this is one equation for multiple unknowns (per energy level)
  • parameterize the energy dependence of t
  • try to describe a spectrum globally

HE, JHEP 0507 011 HANSEN, PRD86 016007 BRICENO, PRD88 094507 GUO, PRD88 014051

matrices in partial-wave space …

for N channels

“Energy-dependent” analysis

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SLIDE 31

USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering & kaon resonances

21

  • Example of coupled-channel scattering
  • Compute finite-volume spectrum

PRL 113 182001 PRD 91 054008

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SLIDE 32

USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering & kaon resonances

21

  • Example of coupled-channel scattering

WICK CONTRACTIONS

  • Compute finite-volume spectrum

PRL 113 182001 PRD 91 054008

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SLIDE 33

USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering & kaon resonances

21

  • Example of coupled-channel scattering

WICK CONTRACTIONS

  • Compute finite-volume spectrum

PRL 113 182001 PRD 91 054008

Large combinatoric factors - contractions expensive

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SLIDE 34

USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering & kaon resonances

22

  • Rest frame “S-wave” spectrum

0.16 0.20 0.24 0.28 16 20 24

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SLIDE 35

USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering & kaon resonances

23

  • Parameterize the t-matrix in a unitarity conserving way
  • vary the parameters, solving

for the spectrum in each irreducible representation & momentum

Want pole mass and couplings of t-matrix

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SLIDE 36

USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering

24

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USQCD All-Hand’s Meeting | May 1, 2015

πK/ηK scattering

24

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USQCD All-Hand’s Meeting | May 1, 2015

Singularity content

25

  • 500
  • 300
  • 100

600 800 1000 1200 1400 1600

  • t-matrix poles as least model-dependent characterization of resonances

broad scalar resonance narrow tensor resonance vector bound-state scalar virtual bound-state

PRL 113 182001 PRD 91 054008

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USQCD All-Hand’s Meeting | May 1, 2015

Impact on experiment

26

. . .

Approved expt: second phase of GlueX program

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USQCD All-Hand’s Meeting | May 1, 2015

Impact on experiment

27 NSAC report prominently featuring exotic meson spectroscopy project Science case for JLab CLAS12 expt New NSAC report in writing now…

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USQCD All-Hand’s Meeting | May 1, 2015

Hadron Spectrum Collaboration

28 JEFFERSON LAB TRINITY COLLEGE, DUBLIN

  • U. OF MARYLAND

TATA, MUMBAI CAMBRIDGE UNIVERSITY Jozef Dudek Robert Edwards Balint Joo David Richards Frank Winter Mike Peardon Sinead Ryan Christopher Thomas Steve Wallace Nilmani Mathur MESON SPECTRUM

PRL103 262001 (2009) PRD82 034508 (2010) PRD83 111502 (2011) JHEP07 126 (2011) PRD88 094505 (2013)

HADRON SCATTERING

PRD83 071504 (2011) PRD86 034031 (2012) PRD87 034505 (2013) PRL113 182001 (2014) PRD91 054008 (2015)

“TECHNOLOGY”

PRD79 034502 (2009) PRD80 054506 (2009) PRD85 014507 (2012) JHEP05 021 (2013)

BARYON SPECTRUM

PRD84 074508 (2011) PRD85 054016 (2012) PRD87 054506 (2013) PRD90 074504 (2014) arXiv:1502.01845

MATRIX ELEMENTS

arXiv:1501.07457 PRD90 014511 (2014)

& postdocs, students

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USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

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SLIDE 43

USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

  • Spectroscopy program maturing
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SLIDE 44

USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

  • Spectroscopy program maturing
  • First phase:
  • Unphysical pion masses
  • Using only “single-hadron” operators gives a sketch of spectrum
  • Suggests rich spectrum of baryons
  • See evidence of exotic and non-exotic mesons - suggests hybrids

➡ Has had direct impact on JLab expt. program

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SLIDE 45

USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

  • Spectroscopy program maturing
  • First phase:
  • Unphysical pion masses
  • Using only “single-hadron” operators gives a sketch of spectrum
  • Suggests rich spectrum of baryons
  • See evidence of exotic and non-exotic mesons - suggests hybrids

➡ Has had direct impact on JLab expt. program

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SLIDE 46

USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

  • Spectroscopy program maturing
  • First phase:
  • Unphysical pion masses
  • Using only “single-hadron” operators gives a sketch of spectrum
  • Suggests rich spectrum of baryons
  • See evidence of exotic and non-exotic mesons - suggests hybrids

➡ Has had direct impact on JLab expt. program

  • Have demonstrated viability of finite-volume methods
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SLIDE 47

USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

  • Spectroscopy program maturing
  • First phase:
  • Unphysical pion masses
  • Using only “single-hadron” operators gives a sketch of spectrum
  • Suggests rich spectrum of baryons
  • See evidence of exotic and non-exotic mesons - suggests hybrids

➡ Has had direct impact on JLab expt. program

  • Have demonstrated viability of finite-volume methods
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SLIDE 48

USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

  • Spectroscopy program maturing
  • First phase:
  • Unphysical pion masses
  • Using only “single-hadron” operators gives a sketch of spectrum
  • Suggests rich spectrum of baryons
  • See evidence of exotic and non-exotic mesons - suggests hybrids

➡ Has had direct impact on JLab expt. program

  • Have demonstrated viability of finite-volume methods
  • Near term goals
  • Use multiple volumes at mπ ~230MeV and 391MeV
  • Test three-body formalism

➡ Knowledge of even size of branching fractions useful for expt. analysis

slide-49
SLIDE 49

USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

  • Spectroscopy program maturing
  • First phase:
  • Unphysical pion masses
  • Using only “single-hadron” operators gives a sketch of spectrum
  • Suggests rich spectrum of baryons
  • See evidence of exotic and non-exotic mesons - suggests hybrids

➡ Has had direct impact on JLab expt. program

  • Have demonstrated viability of finite-volume methods
  • Near term goals
  • Use multiple volumes at mπ ~230MeV and 391MeV
  • Test three-body formalism

➡ Knowledge of even size of branching fractions useful for expt. analysis

slide-50
SLIDE 50

USQCD All-Hand’s Meeting | May 1, 2015

Summary

29

  • Spectroscopy program maturing
  • First phase:
  • Unphysical pion masses
  • Using only “single-hadron” operators gives a sketch of spectrum
  • Suggests rich spectrum of baryons
  • See evidence of exotic and non-exotic mesons - suggests hybrids

➡ Has had direct impact on JLab expt. program

  • Have demonstrated viability of finite-volume methods
  • Near term goals
  • Use multiple volumes at mπ ~230MeV and 391MeV
  • Test three-body formalism

➡ Knowledge of even size of branching fractions useful for expt. analysis

  • Switch to isotropic lattices at physical limit