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Letizia ParatoFinal presentation23 September 2016
ντ appearance optimization
• DUNE experiment design– Target hall– Magnetic horns– Different targets
• ντ physics• ντ appearance optimization
– Target and the second horn placement• νμ fluxes
– Second horn rescale– Target optimization
• Work left to do toward optimization• Conclusions
Outline
9/23/16 Letizia Parato | Final presentation2
DUNE experiment
9/23/16 Letizia Parato | Final presentation3
DUNE experiment design
9/22/16 Letizia Parato | Final presentation4
Target hall
TargethallinreferencedesignwithtwoNuMIhorns
Threehornsfortheop7mizeddesign
(be<erforlowenergyexperiments)
beam
DUNE experiment design
9/23/16 Letizia Parato | Final presentation5
Magnetic hornsPARABOLICHORN• Focusesagivenmomentumforallpossibleanglesof
entryintothehorn.• Foragivenshapeandcurrentthefocallengthofthe
hornispropor7onaltothepar7clemomentum.• Highenergypar7clescouldbeunderfocused(notfully
strengthen)whilelowenergypar7clescouldbeoverfocused.
NuMItarget47graphitetargetsegments,each2cmlongandspaced0.2mmapart,10mminwidth
DUNE experiment design
9/22/16 Letizia Parato | Final presentation6
Different targets
Mul7spherestargetHeliumcooledsphericalarray
CylindricaltargetHeliumcooledgraphiterod
Inthetheoryofoscilla7onsflavourstatesaresuperposi7onsofmasseigenstateswhereα=e,μ,τ.Herethecomputa7onoftheoscilla7onprobabilityismadebyOscProbability.CimplementedintheLBNFcode.Parametersareupdatedto2016andthedistanceatwhichoscilla7onsareobservedis1294km(DUNEfardetector).
ντ physics
9/23/16 Letizia Parato | Final presentation7
Neutrino oscillation probability
Energy (GeV) 0 2 4 6 8 10
Oscil
lation
prob
abilit
y
00.10.20.30.40.50.60.70.80.9
1 = 0CPδ
/2π = -CPδ probabilityµν → µν
Energy (GeV) 0 2 4 6 8 10
Oscil
lation
prob
abilit
y
00.05
0.10.150.2
0.250.3
0.350.4
0.450.5
= 0CPδ/2π = -CPδ
probabilityeν → µν
Energy (GeV) 0 2 4 6 8 10
Oscil
lation
prob
abilit
y
00.10.20.30.40.50.60.70.80.9
1 = 0CPδ
/2π = -CPδ
probabilityτν → µν
ντ physics
9/23/16 Letizia Parato | Final presentation8
ντ : why, how and what we already know
WHYTotesttheunitarietyofPNMSmatrix.HOW• ντareonlydis7nguishableinCCinterac7ons,whentheyproduceataulepton.
Sincetauisheavy,neutrinoshouldhaveaminimumenergyof3.5GeVtointeractwiththedetector.
• Highenergypionsareneededtoproducehighenergyneutrinos.• Isnecessarytomovethetargetfarfromhorn1tocutlowenergyneutrinos
outofthebeamandtoimprovethefocusingsystem.WHATWEKNOWNottoomuch…5eventsfromOpera(fromoscilla7ons)and12fromDONUT(fromDsdecay)
ντ physics
9/22/16 Letizia Parato | Final presentation9
ντ appearance probability at DUNE far detector
Energy (GeV)0 5 10 15 20 25 30
Prob
abilit
y
00.10.20.30.40.50.60.70.80.9
1 oscillation probabilityτν → µν
Energy (GeV)0 5 10 15 20 25 30
)2 (c
mC
Cσ
0
2
4
6
8
10
12 CC cross sectionτν
Energy (GeV)0 5 10 15 20 25 30
)2 x
osc
. pro
babi
lity
(cm
CC
σ 0
0.05
0.1
0.15
0.2
0.25
0.3 CC appearance probability at FDτν
Crosssec7onevaluatedbyGENIEincludedintheLBNFcode
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation10
Reference vs. optimized designOp7mizeddesign128ντCCeventsatFDper40ktonperyearStandarddevia7on=8Meanerror=1
Referencedesign225ντCCeventsatFDper40ktonperyearStandarddevia7on=55Meanerror=3
ντ appearance optimizationReference vs. optimized design
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation12
Target and second horn placementSetups for the simulation
§ Buffle not installed§ Shield not installed§ Decay pipe snout not installed§ Horns
o 230 kA currento 1.2 MW
§ Beamo 120 GeV proton momentumo Beam sigma X = 1.7 mm o Beam sigma Y = 1.7 mm
§ NuMI target o Graphiteo Fin width = 10.0 mmo Target length = 1 m
100 jobs with 100k POT eachfor different distances of the target and of horn 2 from the zero point.
For each set I looked for the number of ντ CC events per year per 40 kton (fiducial LArTPC detector mass)
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation13
Target and second horn placement
first-second horn distance (m)6 7 8 9 10 11 12 13 14 15 16 17 18
targ
et-fi
rst h
orn
dist
ance
(cm
)
45
75
105
135
165
195
225
255
285
315
345
375
405
435
465
495
0
100
200
300
400
500
600
700
261 279 302 330 329 366 376 395 412 422 434 440
383 402 418 435 467 479 497 511 526 532 548 559
471 489 508 535 540 561 582 600 617 626 638 645
529 553 565 585 605 614 635 648 664 682 694 697
566 574 592 605 619 638 652 672 677 708 710 724
568 580 599 600 618 633 649 668 677 691 709 725
570 575 580 600 607 614 636 652 670 677 685 707
526 550 568 600 593 603 617 624 634 651 667 680
527 534 546 550 554 579 584 596 612 632 632 653
503 506 516 524 533 541 553 565 578 590 612 614
478 487 488 497 508 510 521 540 542 561 587 584
463 471 470 482 484 503 507 530 519 539 555 565
380 380 382 384 389 392 398 424 426 436 443 453
101 102 103 102 114 105 112 114 112 121 126 126
16 17 17 18 17 17 19 20 19 20 21 21
cc events over target and horns distanceτν
ντ appearance optimization
9/23/16 Letizia Parato | Final presentation14
Target and second horn placement
• Horn2hastobeplacedasfaraspossible(17.5m)
• Thetargethastobe
placedabout2mfarfromthehorn1beginning.
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation15
Target and second horn placementνμ fluxes
Energy (GeV)0 5 10 15 20 25 30
/ PO
T2
s / G
eV /
mµν
Uno
sc
0
5
10
15
20
25
3012−10×
flux - target at 90 cm from zeroµν
Horn 2 at 75 m from zero
Horn 2 at 95 m from zero
Horn 2 at 115 m from zero
Horn 2 at 135 m from zero
Horn 2 at 155 m from zero
Horn 2 at 175 m from zero
Energy (GeV)0 5 10 15 20 25 30
/ PO
T2
s / G
eV /
mµν
Uno
sc
0
5
10
15
20
25
3012−10×
flux - target at 210 cm from zeroµν
Horn 2 at 75 m from zero
Horn 2 at 95 m from zero
Horn 2 at 115 m from zero
Horn 2 at 135 m from zero
Horn 2 at 155 m from zero
Horn 2 at 175 m from zero
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation16
Target and second horn placementNeutrino parents: how they contribute to the flux
UnoscνμfluxatFD[targetat2.1m-horn2at17.5mfromhorn1]
• AlmostallneutrinoscomefromthedecayofPions
• Kaonscontributetothehighenergytailofthedistribu7on
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation17
Target and second horn placementνμ fluxes
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation18
Target and second horn placementνμ fluxes
Oscillated
ντCCEven
ts/Ge
V/k
Ton/P
OT
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation19
Second horn rescaleSetups for the simulation
§ Buffle not installed§ Shield not installed§ Decay pipe snout not installed§ Horns
o 230 kA currento 1.2 MW
§ Beamo 120 GeV proton momentumo Beam sigma = 1.7 mm
§ NuMI target o Graphiteo Fin width = 10.0 mmo Target length = 1 m
§ Target 2 m far from zero§ Second horn 17.5 m far from zero
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation20
Second horn rescale
ντ appearance optimization
9/22/16 Letizia Parato | Final presentation21
Second horn rescale
70% radial scaling 100% longitudinal scalingPROCost less ?CONSMore mechanical stress ?
80% radial scaling120% longitudinal scalingCONSIt would be necessary to move horn 2 at 16.5 m from horn 1 losing flux
Is it better to enlarge horn 2 or to make it smaller?
This configuration will be used for the cylindrical and
spherical target simulations
ντ appearance optimization
9/23/16 Letizia Parato | Final presentation22
Target optimization2.0 m long NuMI target
first-second horn distance (m)75 95 115 135 155 175
targ
et-fi
rst h
orn
dist
ance
(cm
)
150
180
210
240
270
300
330
360
390
420
450
0
100
200
300
400
500
600
700
477 508 545 575 601 620
509 545 579 608 633 656
521 548 581 605 634 663
523 546 575 605 633 646
501 523 549 585 601 630
496 502 521 558 579 605
466 476 509 517 547 573
435 454 464 483 508 445
443 476 465 505 521 535
476 485 497 520 548 568
482 482 512 537 553 589
cc events over target and horns distance [2 m target]τν
8.5 % less events respect to the 1 m target configuration
ντ appearance optimization
9/23/16 Letizia Parato | Final presentation23
Target optimization
13 m
m d
iam
eter
17 m
m d
iam
eter
CC
per
yea
r per
40
kton
τν
770
780
790
800
810
820
830
840
Beryllium spherical target
target length (cm)100 120 140 160 180 200
CC
per
yea
r per
40
kton
τν
800
805
810
815
820
825
830
835
840
845
Beryllium spherical target13 mm vs. 17 mm diameter [1m long target] 13 mm diameter target – events over target length
Multi sphere Beryllium target
ντ appearance optimization
9/23/16 Letizia Parato | Final presentation24
Target optimizationCylindrical simple Graphite target
length (cm)100 120 140 160 180 200
diam
eter
(mm
)
3
3.5
4
4.5
5
5.5
6
650
700
750
800
850
900
950
1000
1050
968 993 1015 1003 1008 1009
929 950 959 977 979 963
899 912 940 923 934 925
874 890 892 902 891 881
849 857 857 854 853 852
845 840 831 829 817 822
812 800 814 797 787 783
Cylindrical Targetντ CC events at FD per 40kton per year over cylindrical target scaling
radius
(mm)
ντ appearance optimization
9/23/16 Letizia Parato | Final presentation25
Target optimizationCylindrical simple Graphite target
More realistic 5 mm radius target3 mm radius target
Work left to do toward optimization
9/23/16 Letizia Parato | Final presentation26
τ decay channels and signal reconstructionNeutrino’sflavorcanbedetectedonlyinCCevents.Thefollowingtableshowstheτdecaychannelsthatthedetectorisabletoresolveandtheirrela7vebranchingra7o.
Everydecaychannelhashisownbackgroundwhichhastobeevaluatedinordertoes7matethereconstruc7onefficiency.
Work left to do toward optimization
9/23/16 Letizia Parato | Final presentation27
1. Try target with lower densityFor example a cylindrical target composed by many little cylinders separates by thin layers of air.
2. Using a genetic algorithm Set parameters near to the ones I found and apply a genetic algorithm to find the very best geometry for the ντ appearance.
3. Estimate reconstruction efficiencySimulate CC events at far detector and evaluate the relevant background for the CC event occurred. Find neutrino energy threshold under whom it is not possible to distinguish the signal from the background.
In LArTPC the reconstruction efficiency can be around 20%;
Conclusions
9/23/16 Letizia Parato | Final presentation28
• Thesecondhornhastobeplacedasfaraspossiblefromthefirsthorn.• Thetargethastobeplacedabout2mdistantfromthefirsthorn.• Thesecondhornhasmorefocusingpowerifradiallyrescaledofabout75%
(andallpropor7onalconfigura7ons).• Athinnertargetwithlowdensityworksbe<er.• Athinnertargetcanbemadelongerwithoutreducing(ormaybeincreasing)
thenumberofevents:thisisgoodbecauselongertargetmeanslessenergydepositedintheabsorber.
• Igotamaximumof880ντCCeventsper40ktonperyearusinga(realis7c)cylindricaltargetwith5mmofradiusand150cmoflength.Thismeansafactorof4respecttothereferencedesignandafactorof8respecttotheop7mizedthreehornsdesign.
• Alotofworkhass7lltobedoneto• findthebestgeometry,• es7matethereconstruc7onefficiency.
IpresentedtheseresultstwicetotheBeamInterfaceGroupduringthegroupmee7ng.
Thank you
9/23/16 Letizia Parato | Final presentation29
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