Cosmic Rays: AMS Experiment Javier Berdugo (CIEMAT, Madrid)

Frontiers of Astroparticle Physics. La Palma October 11th 2018

P. Mertsch arXiv: 1012.4239 [astro-ph.HE]

Cosmic rays are a sample of solar, galactic and extragalactic matter which

includes all known nuclei and their isotopes, as well as electrons, positrons and antiprotons

Cosmic rays

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Sci. Amer. 276 (1997) 44

p, He + ISM antiparticles + …

+ antiparticles + …

EARTH

p, He

antiparticles

ISM

The collision of cosmic rays with interstellar medium (ISM) produces antiparticles (e+, p, D, …)

The collision of dark matter particles will produce additional antiparticles

Antiparticles in Cosmic Rays and Dark Matter

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Positrons in Cosmic Rays

m=800 GeV

I. Cholis et al., arXiv:0810.5344

m=400 GeV

e± energy [GeV]

e+ /

(e+ +

e- )

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M. S. Turner and F. Wilczek, Phys. Rev. D42 (1990) 1001;

J. Ellis, 26th ICRC Salt Lake City (1999) astro-ph/9911440;

H. Cheng, J. Feng and K. Matchev, Phys. Rev. Lett. 89 (2002) 211301;

S. Profumo and P. Ullio, J. Cosmology Astroparticle Phys. JCAP07 (2004) 006;

D. Hooper and J. Silk, Phys. Rev. D 71 (2005) 083503;

E. Ponton and L. Randall, JHEP 0904 (2009) 080;

G. Kane, R. Lu and S. Watson, Phys. Lett. B681 (2009) 151;

D. Hooper, P. Blasi and P. D. Serpico, JCAP 0901 025 (2009) 0810.1527; B2

Y–Z. Fan et al., Int. J. Mod. Phys. D19 (2010) 2011;

M. Pato, M. Lattanzi and G. Bertone, JCAP 1012 (2010) 020.

Precision measurements of antiparticles requires long exposure time

with detectors with large acceptance and percent level precision.

Flux of antiparticles in cosmic rays

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Experiments operating outside the atmosphere and capable to measure

simultaneously the spectra of the different cosmic ray components.

O. Adriani et al. Nature 458 (2009)

M. Ackerman et al. Phys. Rev. Lett. 108 (2012) 011103

PAMELA: Launched on June 15th 2006

Image: http://wizard.roma2.infn.it/pamela/html/resurs.html

Baikonur Cosmodrome (Kazakhstan)

FERMI Launched on June 11, 2008

Image credit: NASA/Jerry Cannon, Robert Murray

Space based cosmic ray experiments

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CALET, started August 2015

ISS CREAM, started August 2017

AMS, started May 2011

DAMPE, started December 2015

Space-born Cosmic Ray Experiments in operation

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5m x 4m x 3m

7.5 tons

TRD

TOF 1, 2

TOF 3, 4

RICH

ECAL

Magnet and

Veto Counters

Silicon layer 1

Silicon layers 2 - 8

Silicon layer 9

Acceptance: 0.5 m2 sr 08/07/2014 8

USA

MEXICO

UNAM

UNIV. OF TURKU

ASI IROE FLORENCE

INFN & UNIV. OF BOLOGNA INFN & UNIV. OF MILANO-BICOCCA INFN & UNIV. OF PERUGIA

INFN & UNIV. OF PISA INFN & UNIV. OF ROMA

INFN & UNIV. OF TRENTO

NETHERLANDS

ESA-ESTEC NIKHEF

RUSSIA

ITEP KURCHATOV INST.

SPAIN

CIEMAT - MADRID I.A.C. CANARIAS.

ETH-ZURICH UNIV. OF GENEVA

CALT (Beijing) IEE (Beijing)

IHEP (Beijing) NLAA (Beijing) BUAA(Beijing)

SJTU (Shanghai) SEU (Nanjing)

SYSU (Guangzhou) SDU (Jinan)

EWHA KYUNGPOOK NAT.UNIV.

PORTUGAL

LAB. OF INSTRUM. LISBON

ACAD. SINICA (Taipei) CSIST (Taipei)

NCU (Chung Li) NCKU (Tainan)

TAIWAN

TURKEY

METU, ANKARA

CER

N=

JSC

DOE-

NASA

LUPM MONTPELLIER LAPP ANNECY

LPSC GRENOBLE

FRANCE

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BRAZIL

IFSC – SÃO CARLOS INSTITUTE OF PHYSICS

RWTH-I. Aachen KIT-KARLSRUHE

SWITZERLAND

MIT

KOREA

GERMANY

FINLAND

ITALY

CHINA

AMS is an international collaboration based at CERN

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It took 650 physicists and engineers 17 years to construct AMS

Ground Tests and Calibrations Space Qualification (EMI and TV at ESTEC)

1,762 positions and angles with p, e+, e−, pion beams

from 10 to 400 GeV/c

TVT Chamber: P < 10-9 bar Ambient temperature: -90oC to 40oC

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Test Beam at CERN (Calibration)

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237<|R|<290 GV

Positron measurement with AMS

Signal identification from 2D template fit in (∧TRD - ∧CC ) plane

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Positron fraction in cosmic rays with AMS

1 10 100 1000

Energy [GeV]

0

50

100

150

200

250]2

GeV

-1sr

-1s

-2 [

m3

E-

eF

0

5

10

15

20

25 ]2

GeV

-1sr

-1s

-2 [

m3

E+

eF

Latest AMS results on positron and electron fluxes

28.1 million electrons

1.9 million positrons

Energy range from 0.5 GeV to 1 TeV

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Astrophysical point sources like pulsars will imprint a higher anisotropy on the arrival directions of energetic positrons than a smooth dark matter halo.

positrons Isotropic Map

C1 is the dipole moment

The anisotropy in galactic coordinates

Amplitude of the dipole anisotropy on positrons for 16 < E < 350 GeV δ < 0.019 (95% C.I.)

AMS Positron cosmic ray anisotropy

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Models based on very different assumptions describe observed trends of a single measurement.

Positron flux modeling

Many models proposed to explain the physics origin of the observed behavior

1) Particle origin: Dark Matter 2) Astrophysics origin: Pulsars, SNRs 3) Propagation of cosmic rays

Simultaneous description of several precision measurements is difficult in the framework of a

single model

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⦁ 1.9 million positrons

1.2 TeV Dark Matter + Collision of Cosmic Rays

The positron flux appears to be in agreement with predictions

from a 1.2 TeV Dark Matter model (J. Kopp, Phys. Rev. D 88, 076013 (2013))

(e+ + e–) AMS data: comparison with other detectors

Measuring (e++e–) is much less sensitive to detect the source term due to the large e– background

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(e+ + e–) AMS data: comparison with other detectors

The Antiproton Flux is ~10-4 of the Proton Flux. A percentage precision experiment requires background rejection

close to 1 in a million

Kinetic energy [GeV]

An

tip

roto

n / p

roto

n r

ati

o

Donato et al.,

PRL 102, 071301 (2009)

Dark matter

10-4

10-5

10-6

10-7

10-3

10-2

1 10 100 1000

Dark matter + Collision of

cosmic rays

with ISM

Antiprotons in Cosmic rays

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p

e

p

175<|R|<211 GV

χ2/d.f. = 138/154

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Antiproton measurement with AMS

Signal identification from 2D template fit in (∧TRD - ∧CC ) plane

p 3.49105 events

• AMS-02

o PAMELA

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Antiproton-to-Proton Flux Ratio

M. Aguilar et al. Phys. Rev. Lett. 117 (2016) 091103

Show no rigidity dependence above 60 GV

G.Giesen, et. al., JCAP 09 (2015) 023

C.Evoli et. al., JCAP 12 (2015) 039

R.Kappl, et. al., JACP 10(2015) 034

Collision of cosmic rays with interstellar medium:

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Primary and secondary cosmic ray

08/07/2014 23

PDG, Phys. Rev. D86, 010001 (2012)

A. Obermeier et al. Astrophys. J. 742 (2011) 14

Understanding the origin, acceleration and propagation of CR require the

knowledge of the chemical composition over a wide energy range

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Primary and secondary Cosmic Rays Comparison with earlier measurements

M. Aguilar et al. Phys. Rev. Lett. 120 (2018) 021101 M. Aguilar et al. Phys. Rev. Lett. 119 (2017) 251101

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Primary and secondary Cosmic Rays with AMS

Secondary/Primary Flux Ratios = KRΔ

Combining the six ratios,

the secondary over primary flux ratio (B/C, …),

deviates from single power law above 200 GV by 0.13±0.03

Δ[200-3300GV] – Δ[60-200GV] = 0.13±0.03

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0 G

V

20

0 G

V

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[GV]R~

Rigidity

3 4 5 10 20 210 210´23

103

10´2

] 1.7

GV

-1s

r-1

s-2

[ m

2.7

R´

NF

5

10

15

20

25

a) AMS

SNF+P

NF=NF

BF´= 0.62S

NF; OF´= 0.09PNF

Primary Component

Secondary Component

Nitrogen Cosmic Rays

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AMS

ΦN = ΦNP+ΦN

S

ΦN = ΦNP+ΦN

S = (0.090±0.002)×ΦO+(0.62±0.02)×ΦB

M. Aguilar et al. Phys. Rev. Lett. 121 (2018) 051103

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3He/4He abundancies

Preliminary data, refer to upcoming AMS PRL publication

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AMS continous measurement of the e+ and e- flux in the energy range 1 -50 GeV

over 6 years with a time resolution of 27 days.

M. Aguilar et al. Phys. Rev. Lett. 121 (2018) 051102

Anti Deuterons have been proposed as an almost background free channel for Dark Matter indirect detection

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Anti Deuterons in Cosmic rays

The Anti Deuterons Flux is < 10-4 of the Antiproton Flux. Additional background rejection

1 4 10 40 100

10-6

10-8

10-10

Rigidity [GV]

Flu

x [

(m2 s

r s

GV

)-1]

D from collisions of

ordinary cosmic rays

D from annihilation

of Dark Matter

Dark Matter model: F. Donato et al., Phys. Rev. D, 62 (2000) 043003

Collisions of CR model K. Blum et al., Phys. Rev. D 96 (2017) 103021)

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Anti-deuterons have never been observed in space

BESS results (COSPAR 2018)

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Anti-Deuteron Search with AMS

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Anti-Deuteron Search prospects

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Y

Z

X

First anti-Helium event in the cosmos:

Momentum = 33.1 ± 1.6 GeV/c Charge = -1.97 ± 0.05 Mass = 2.93 ± 0.36 GeV/c2

Mass (3He) = 2.83 GeV/c 2

Date: 2011-269:11:19:32

Anti-Helium Search with AMS

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3He flux models from collisions of cosmic rays

There are large uncertainties in models to ascertain the origin of 3He The rate of anti-helium is ~1 in 100 million helium.

We have also observed two 4He candidates. More events are necessary to ensure that there are no backgrounds.

Kinetic Energy/nucleon

model variations factor of ~300

K. Blum et al., Phys. Rev. D 96, 103021 (2017)

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High precision measurements of cosmic rays open new windows to observe unexpected phenomena

There are several large scale detectors in space to study high energy charged cosmic rays:

AMS, CALET, DAMPE, ISS-CREAM exploring a new and exciting frontier in physics research

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