(e +e ) Analysis: Status Report · (e++e-) Analysis: Status Report ... (pure sample selection,...
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Valerio Vagelli Valerio Vagelli University of Perugia - I.N.F.N. Perugia (IT) (e + +e - ) Analysis: Status Report • Comparison with other measurements • Energy scale • Data driven signal identification above 1 TeV (for the whole group: M. Duranti, M. Crispoltoni, F. Nozzoli, V. Vagelli)
Transcript of (e +e ) Analysis: Status Report · (e++e-) Analysis: Status Report ... (pure sample selection,...
Valerio Vagelli
Valerio Vagelli University of Perugia - I.N.F.N. Perugia (IT)
(e++e-) Analysis: Status Report
• Comparison with other measurements
• Energy scale
• Data driven signal identification above 1 TeV
(for the whole group: M. Duranti, M. Crispoltoni, F. Nozzoli, V. Vagelli)
Valerio Vagelli
State of the Art!Gamma Ray
Energy (GeV)1 10 210 310
)-1
sr s
ec ]
2 [
m2
(GeV
Φ × 3 E
050
100150200250300350400
AMS-02
Fermi-LAT (2017)
DAMPE (2017)
CALET (2017)
AMS-02 (2014, pass4)
Fermi-LAT (2017, “pass8”)
DAMPE (2017)
CALET (2017)
Low energies <100 GeV: DAMPE systematically higher High energies: [100, 1000] GeV AMS&CALET vs DAMPE&FERMI TeV energies: DAMPE and FERMI disagree DAMPE and CALET converge
Valerio Vagelli
State of the Art!Gamma Ray
AMS-02 (2014, pass4)
Fermi-LAT (2017, “pass8”)
DAMPE (2017)
CALET (2017)
Energy (GeV)210 310
bΦ/ a
Φ
0.6
0.81
1.2
1.4
1.6
1.8
2AMS-02 / DAMPE
Fermi-LAT (2017) / DAMPE
CALET / DAMPE
AMS-02 / DAMPE
Fermi-LAT / DAMPE
CALET / DAMPE Flux
Rat
io
DAMPE: 5% shift w.r.t. others
Valerio Vagelli
but since the experimental quantity is
N /Z
�E�(E) dE
����d�rec
�rec
���� ⇠ (� � 1)dE
E
�(E) / E�� )����d�
�
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E
Since electron flux is ~ E-3: • 1.25% shift in energy -> ~2.5% shift in the flux; • 2.50% shift in energy -> ~5.0% shift in the flux;
Energy Scale Uncertainty!
2% @ 300 GeV 4% @ 700 GeV
Valerio Vagelli
Energy (GeV)210 310
bΦ/ a
Φ
0.6
0.81
1.2
1.4
1.6
1.8
2State of the Art!
Gamma Ray
AMS-02 / DAMPE (with AMS energy scale systematics)
Flux
Rat
io
Valerio Vagelli
State of the Art!Gamma Ray
AMS-02 (2014, pass4)
Fermi-LAT (2017, “pass8”)
DAMPE (2017)
CALET (2017)
Energy (GeV)1 10 210 310
)-1
sr s
ec ]
2 [
m2
(GeV
Φ × 3 E
050
100150200250300350400
AMS-02
Fermi-LAT (2017)
DAMPE (2017)
CALET (2017)
AMS-02 (2014, pass4)
Fermi-LAT (2017, “pass8”)
DAMPE (2017) – shifted by 5% (ΔE/E = 2.5%)
CALET (2017) Energy scale uncertainty -- may explain low energy differences -- cannot explain high energy differences
Valerio Vagelli
Energy (GeV)210 310
bΦ/ a
Φ
0.6
0.81
1.2
1.4
1.6
1.8
2AMS-02 / DAMPE (shifted)
Fermi-LAT (2017) / DAMPE (shifted)
CALET / DAMPE (shifted)
State of the Art!Gamma Ray
AMS-02 / DAMPE
Fermi-LAT / DAMPE
CALET / DAMPE Flux
Rat
io
DAMPE: shifted by 5% Residual AMS/DAMPE shift is not covered by our scale uncertainty
Valerio Vagelli
ECAL satura7on!M
ax. E
nerg
y D
ep. i
n ce
ll • ECAL saturation effect pointed out by W. Xu
• Possible source: light yield saturation in fibers
Shower Energy (GeV)
W. Xu
W. Xu
Valerio Vagelli
3D Shower Reconstruc7on!• ECAL reconstruction algorithm based on parametrization of 3D shower profile
• Accounts and corrects for saturation • Introduces redefined ECAL e/h separation tools (to be tested, already in the
new ntuples)
W. Xu W. Xu
Valerio Vagelli
3D Shower Reconstruc7on!• Expected effect on the flux measurement
• Correction for saturation effect and leakage does not recover the discrepancies observed in the [70 – 500] GeV range
• The whole analysis has to be rerun with the new energy definition for a more robust statement
Energy (GeV)210 310
)-1
sr s
ec ]
2 [
m2
(GeV
Φ × 3 E 6080
100120140160180200220240
AMS-02AMS-02 (shifted)Fermi-LAT (2017)DAMPE (2017)CALET (2017)
Energy (GeV)210 310
bΦ/ a
Φ0.60.70.80.91
1.11.21.31.4
Flux
Rat
io (A
MS/
DAM
PE)
red band = AMS energy scale syst.
Valerio Vagelli
The measurement above 1 TeV !• The 2014 analysis based on:
• Removal of proton background using a >95% efficient ECAL cut • Data Driven signal identification: Fit of residual background and (e++e-)
signal using TRD template fit • TRD template based on e-likelihood (universal template) instead of e/p
likelihood ratio (higher separation but energy dependent) • Systematic uncertainty above 500 GeV mostly due to uncertainty in the
data-driven definition of proton templates
Valerio Vagelli
The measurement above 1 TeV !
• TRD separation power saturates above 1 TeV
• Could not find robust procedure to construct ECAL BDT templates
MAIN LIMIT:
Valerio Vagelli
MC-‐free signal iden7fica7on!MC FREE approach for 2D ECAL+TRD signal identification
• Definition of three samples: R>0, R<0, R=? (larger CC)
• Cut on ERAT to remove correlation between ECAL and TRD
• TRD-likelihood data driven templates • electron template: universal • proton template: energy parametrization
• ECAL-BDT data driven templates • “Median” method exploiting the knowledge of TRD template • energy parametrization
• ECAL+TRD 2D fit
Valerio Vagelli
MC-‐free signal iden7fica7on!MC FREE approach for 2D ECAL+TRD template definition • Preliminary cut on ERAT (Edep/Erec) to remove correlations
F. Nozzoli
Valerio Vagelli
MC-‐free signal iden7fica7on!MC FREE approach for 2D ECAL+TRD template definition • TRD Proton templates parametrized vs Energy assuming asymptotic convergence
F. Nozzoli
Valerio Vagelli
MC-‐free signal iden7fica7on!MC FREE approach for 2D ECAL+TRD template definition • Data driven definition of ECAL templates using extended “median” method
Valerio Vagelli
MC-‐free signal iden7fica7on!MC FREE approach for 2D ECAL+TRD template definition • Data driven definition of ECAL templates using extended “median” method • Parametrization of ECAL-BDT shape where statistics is poor
F. Nozzoli
Valerio Vagelli
MC-‐free signal iden7fica7on!MC FREE approach for 2D ECAL+TRD template definition • 2D ECAL + TRD template fit
F. Nozzoli
Valerio Vagelli
MC-‐free signal iden7fica7on!MC FREE approach for 2D ECAL+TRD template definition • 2D ECAL + TRD template fit
F. Nozzoli
Valerio Vagelli
MC-‐free signal iden7fica7on!MC FREE approach for 2D ECAL+TRD template definition • 2D ECAL + TRD template fit
F. Nozzoli
Valerio Vagelli
MC-‐free signal iden7fica7on!
• Data-driven measurement up to 1.5 TeV possible • Observation of “break” @ 1 TeV • Systematics check
Energy (GeV)100 1000
-1 )-2
s s
r GeV
2 (m3 E×
Flux
50
100
150
200
DAMPE CALET FERMI AMS02
AMS Data-Driven
PRELIMINARY May 2011 – Dec 2016
F. Nozzoli F. Nozzoli
Valerio Vagelli
New Tracker reconstruc7on !
Valerio Vagelli
New Tracker reconstruc7on !
Carbon Electrons ~0.2
• Relevant improvement in rigidity resolution for e+/- (Bremmstrahlung) • Fundamental for separate e+/- and PF measurements • May provide improvements also for (e++e-) analysis (pure sample selection,
template definition, E/R efficiency,…) • Released in mid-Jan, ntuples have to be reprocessed to include the new fit algo
Rigidity resolution Q. Yan
Valerio Vagelli
Outlook !• Processing of ntuples with recent ECAL reconstruction just finished.
• Will reprocess the “pass4 – TRD template fit” analysis up to 1 TeV. No sensitivity expected to extend the measurement above 1 TeV.
• 2D ECAL+TRD analysis almost finalized, just be processed over the latest data
• Normalization of the flux (acceptance + corrections) have to be updated based on the new MC.
• Further improvement in reconstruction may turn out to be useful. They will be included in the future production of ntuples.
