Download File - AMS02 BOLOGNA

AMS-02, Antimatter, Strangelets, Cosmic Rays
Nicolò Masi
May 2012
Bologna University and INFN
The CPT theorem
assures that any particle species there exists the
antiparticle with exactly the same mass and decay width and eventually
opposite charges.
This striking symmetry would naturally lead us to conclude that the Universe
contains particles and antiparticles in equal number densities.
The observed Universe is drastically different. We do not observe any bodies
of antimatter within the solar system and only antiprotons in the cosmic
rays, which are believed to be of extra solar origin. Antiprotons are likely to
be produced as secondaries in collisions:
Search for Antimatter
Antihelium/
Helium Flux
If we reach this value we can affirm
antiworld doesn’t exist
10 years
ANTIMATTER
in this Universe:
And if it really not existed?
Planck Epoch:10-44 ÷10–43 seconds after the Big Bang
Grand Unification epoch
10–43 ÷10–36 seconds after the Big Bang, T ∼ 1015 GeV
Gravitation begins to separate from the fundamental gauge interactions. Physics
may be described by GUT in which the gauge group of the Standard Model is
embedded in a much larger group, which is broken to produce the observed
forces of nature.
Electroweak epoch
10–36 ÷10–12 seconds after the Big Bang, T ∼ 1014 ÷103 GeV
The temperature of the universe is low enough (1028 K) to separate the strong
force from the electroweak force. This phase transition triggers a period of
exponential expansion known as cosmic inflation. After inflation ends, particle
interactions are still energetic enough to create large numbers of exotic
particles, including W, Z and H.
Inflationary epoch
10–36 ÷10–32 seconds after the Big Bang, T ≲ 1013 GeV
The universe is flattened (its spatial curvature reaches the so called critical
value) and the universe enters a homogeneus and isotropic rapidly expanding.
Some energy from photons becomes virtual quarks and hyperons, but these
particles decay quickly.
According to the ΛCDM model, dark energy is present as a property of space
itself, beginning immediately following the period of inflation.
⇒Reheating
T ∼ 107 ÷104 GeV
The exponential de Sitter-like expansion that occurred during inflation ceases
and the potential energy of the inflaton, the inflation field, decays into a hot,
relativistic plasma of particles. The universe is dominated by radiation; quarks,
electrons and neutrinos form.
⇒ Baryogenesis:
Yes or No?
D
E
Inflaton
We need a correct
amount of CP Violation
A link between B and CP
Standard Model CP
Violation: A Great
Disagreement
A Baryonic
Asimmetry B tiny
value for the
cosmological
synthesis
Dependence of the CMB Doppler peaks on 𝛈
Nucleosynthesis
versus η
Eta determines
light nulei cosmic ratios
Via Electroweak Phase Transition - SM compatible
 Via Leptogenesis - sterile neutrinos
 GUT Processes - SU(5)
 Via Scalar Field
(CPT Violation)

We start from null baryonic number and baryon asimmetry:
B = 0 and 𝛈 = 0
Sakharov Criteria
Anomalous B-violating processes
• B violation
• C & CP violation
• Nonequilibrium
dynamics
Sakharov, 1967
Prevent washout by inverse
processes
How can we create a B
violation?
It induces additional terms in the EW action and not conserved currents
Baryonic
Leptonic
Chiral
The Anomaly is described by the Chern-Simons current
Baryonic
Number
𝐵=
0
𝑑 3 𝑥 𝑗𝐵
Chern-Simons
Number
𝑁𝐶𝑆 =
𝑛𝐹 2
𝑔
32𝜋 2
Non Noether Baryonic
and Leptonic
Currents
B + L not conserved
B - L conserved
𝑁𝐶𝑆
𝑑3𝑥 𝐾 0
This process trades three leptons, one from
each generation, for nine quarks, three
within each generation, and one of each
color per generation. L and B are not
conserved separately , though the quantum
number B − L is.
With a 1° order Phase
Transition, a FTEP and
a calibrated Higgs
Mechanism, we can
trigger the B number
violation process
 A simple modification of the Standard Model that is able to realize the
program of Sakharov is the one suggested by M. Fukugita and T.
Yanagida.
 The Standard Model is extended by adding right-handed neutrinos,
permitting implementation of the see-saw mechanism and providing the
neutrinos with mass. At the same time, the extended model is able to
spontaneously generate leptons from the decays of right-handed
neutrinos.
 Finally, the sphalerons are able to convert the spontaneously
generated lepton asymmetry into the observed baryonic asymmetry.
GUT SO(10):
Majorana Neutrinos
decay out-ofequilibrium
If an asymmetry in the lepton
number is produced, sphaleron
transition, which conserve B - L,
will reprocess it and convert it into
baryon number.
SU(5): Leptoquark
and X Bosons
Departure from
Equilibrium: X
decay – it satisfies
all Sakharov
conditions
scalar
(De Felice, Nasri & MT; Li, Wang, Feng & Zhang)
 If CPT simmetry is broken, 𝛈 asymmetry can be generated in
equilibrium.
 We can’t break CPT explicitly but, if broken spontaneously, we can
generate a baryon asymmetry.
 A single scalar field may be responsible for inflation, baryogenesis
and dark energy.


EW: Only a small window of parameter space in
extensions of the EW theory in which
baryogenesis is viable; severe upper bound on
lightest Higgs boson mass, mh < 120 GeV, stop
mass close to experimental bound and < top
quark mass (Light Higgs and Stop Scenario): truly
disadvantaged by LHC measurements.
Lepto and GUT: Heavy Majorana neutrinos, more
massive than the 10 TeV sphaleron, and
superheavy bosons, with fine tuning.
Or maybe we simply
missed
an
Testability???
antiuniverse…
New Physics: Strangelets
From quark stars
10 years
A lot of new
unexpected
stuff
Cosmic Rays
AMS measures:
• |Z| independently in the Tracker,
TOF and RICH subdetectors
• Momentum in the tracking system.
• Velocity independently by the TOF,
TRD and RICH subdetectors.
CR Propagation Models with DM: Steady-state Parker Equation with a
primary flux source term
Number density
Diffusion coefficient
Convective Galactic Wind
Annihilation Rate
DM Flux Source
Propagation Parameters From
B/C and Be Isotopes Measures
CR Propagation Constraint
Average grammage (traversed matter)
Average residence time in the
Galaxy
Light nuclei ratios to fix the propagation
parameters and improve the accuracy of
GALPROP and DRAGON software