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15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 1
Sources of atmospheric electron neutrinos
A.D. Morozova, S.I.Sinegovsky
15th Baikal Summer School on Physics of Elementary Particles and Astrophysics
Bolshie Koty, 5-12 July 2015
Anna Morozova, Atmospheric neutrinos 2
High energy neutrinos
High energy neutrinos arise from weak decays of hadrons produced in reactions:
• Cosmic rays particles interact with matter (stellar wind, supernova remnant and other substance)
0 0( , , , )p p K K K X
p X
Cosmic rays interact with matter and electromagnetic fields near remote objects to generate cosmogenic neutrinos; Interactions of cosmic rays with the Earth's atmosphere are the source of the atmospheric neutrinos
• or with dense electromagnetic fields near the source through the photo-production of pion:
0 0( , , , )K K K
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 3
Astrophysical neutrinos vs. AN background
Most of uncertainties in calculations of the high-energy background are due to differences of hadronic interaction models especially as to the strange particles production (and charmed ones as well).
The breakthrough in neutrino astrophysics was the
detection of 37 high-energy neutrino-induced events
with energies 30 TeV – 2 PeV from astrophysical
sources in IceCube experiment – 988 days collection
data (2010-2013).
Atmospheric neutrinos are a background for astrophysical neutrinos which one need know.
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 4
Motivation • The atmospheric flux is one order of magnitude less
than the muon neutrino flux, that is comparatively low background for astrophysical neutrinos
• Semileptonic decays of charged and neutral kaons
are the main source of as well as is the spring of significant uncertainties of the calculations because of poor studies of the kaon yield at very high energy
• At energies above 10 TeV the rare decay mode of the short-lived K0-meson, , can contribute significantly to the flux
(V.Naumov,hep-ph/0201310; T. Sinegovskaya, PhD thesis,1999)
e e
e e
e e 0 ( )S e eK e
• Besides, pion-induced K-mesons production (usually ignored), , is also of the interest as a
contribution to the flux. A K X
e e
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 5
Method of the calculation
The calculation is performed on the basis of a method of solving equations of hadron-nuclear cascade, which allows one to take into consideration
nonpower energy spectrum of cosmic rays, a violation of the Feynman scaling of particle production
cross sections, the growth with energy of the total inelastic cross sections
for hadron-nucleus collisions
V.А. Naumov, T.S. Sinegovskaya, ЯФ 63 (2000) 2020;
A.A. Kochanov, T.S. Sinegovskaya, S.I. Sinegovsky, Astropart. Phys. 30 (2008) 219.
( )( ) / EdN E dE E
0 0( , ) / , /d E x dx x E E
( )inelhA E
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 6
Models for the cosmic rays spectrum
In the calculation we used the following the
parameterization of the spectrum and composition of
CR:
• ZS – the model by Zatsepin and Sokolskaya, which
describes well the data of direct measurements in the
experiment ATIC-2 in the range 10-104 GeV and gives
motivated extrapolation to the region of energies up to
100 PeV where spectrum is reconstructed from
extensive air shower measurements
• HGm - a parameterization by Hillas-Gaisser (also
account for the knee of the CR spectrum)
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 7
Sources of electron neutrinos
Decay modeBranching ratio (%)
Critical energy
Life time(с)
5,04 890 ГэВ
40,55 210 ГэВ
0,07 120 ТэВ
100 1,03 ГэВ
3eK
03SeK
03LeK
( ) ( )e ee
0 ( )e ee
( )e ee
( )e ee
3e
81,24 10
85,12 10
100,90 10
62,19 10
cr 20( ) / ( cos )K K Km c H c
cr (0 )k
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 8
Относительные вклады источников
электронных нейтрино
Relative contributions of the decay modes of electron neutrinos flux
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 9
Zenith-angle enhancement of the neutrino fluxesdue to switching on the K-sources
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 10
Zenith-angle enhancement of the neutrino fluxes
Зенитно-угловое распределение электронных нейтрино для E=10 TeV
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 11
Contribution to flux due to K-mesons produced in interaction
Calculated for model HGm+QGSJET-II-03.
Energy, GeV θ=90˚ θ =0˚
102 6 % 1 %
103 7 % 5 %
104 5 % 6 %
A K X
e e
A
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 12
Results
• In this work, we calculated the contributions to the flux of electron neutrinos from the three-particle semileptonic decay modes of charged and neutral K-mesons produced in extensive air showers generated by cosmic rays
• It is shown that the decay of short-lived neutral kaon at energies above 100 TeV gives more than 1/3 of the total flux of electron neutrinos
• Account for the production of K-mesons in the pions-nuclei interactions leads to 5-7 % increased flux in the energy range 102 -104 GeV.
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 13
Thank you!
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 1414
Backup slides
Atmospheric spectrum and the diffuse flux of cosmic neitrions observed in IceCube experiment
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 15
e e
Z(E)-factors
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 17
• Главное событие в нейтринной астрофизике последних двух лет - детектирование 37 (87) событий от астрофизических нейтрино высоких энергий в эксперименте IceCube (ожидалось ~ 15 событий от АМ, АН)
• Атмосферные нейтрино являются фоном к подобным событиям, и его необходимо знать
• Наибольшая неопределенность расчета фона атмосферных нейтрино при энергиях выше 200 ТэВ обусловлена вкладом процессов рождения и распада странных частиц и очарованных частиц
0 0, ,K K K
Астрофизические нейтрино и проблема фона атмосферных нейтрино
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 18
• Энергетический спектр недавно измерен в эксперименте IceCube в интервале энергий 80 ГэВ - 20
ТэВ • Основные источники - распады каонов
и мюонов
• В генерацию потоков при энергиях выше 10 ТэВ может вносить заметный вклад редкая мода распада K0-мезонов (до сих пор не была включена в коды МК)
• Учет генерации К-мезонов во взаимодействии пионов с ядрами :
0 0, ,K K K
e
Постановка задачи
e e
A K X
0 ( )S e eK e
e e
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 19
Target setting (2)
• Main sources of the atmospheric at high
energies are leptonic and semileptonic decays of kaons
charged and neutral kaons
• At energies above 10 TeV the rare decay mode of the
short-lived K0-meson, , can
contribute significantly to the neutrino flux, (Naumov V.,
Sinegovskaya T. PhD Thesis,1999) (up to now was not
taken into account known codes of the Monte Carlo
simulation method
• A contrubution of K-mesons production in the reaction
of pion-nuclei interactions
e e
0 0, ,L SK K K
A K X
0 ( )S e eK e
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 20
Метод расчета
Расчет выполнен на основе метода решения уравнений адрон-ядерного каскада, который позволяет учитывать нестепенной характер первичного спектра космических лучей, нарушение скейлинга сечений рождения частиц и рост с энергией полных неупругих сечений адрон-ядерных столкновений.
Наумов В.А. Синеговская Т.С.
Ядерная физика. 2000. Т. 63. С. 2020-2028.
A.A. Kochanov, T.S. Sinegovskaya, S.I. Sinegovsky,
Astropart. Phys. 30, 219 (2008).
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 21
Параметризация спектра космических лучей
В расчете использовались следующие параметризации спектра и состава КЛ:
ZS – модель В.И.Зацепина и Н.В.Сокольской, хорошо
описывает данные прямых измерений в эксперименте
ATIC-2 в интервале 10-104 ГэВ и дает мотивированную
экстраполяцию на область энергий до 100 ПэВ (где спектр
восстанавливается на основе измеренний широких атмосферных
ливней)
HGm – параметризация Хилласа-Гайссера (также учитывающая
колено спектра КЛ)
V.I. Zatsepin, N.V. Sokolskaya, Astronomy & Astrophys. 458, 1 (2006); Astron. Lett. 33, 25 (2007).
T. Gaisser, Astropart. Phys. 24, 801 (2012)
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 22
Модели адрон-ядерных взаимодействий при высоких энергиях QGSJET-II-03 (Quark Gluon String model with JETs) - расширение модели кварк-глюонных струн (QGSM), включающее адронные струи - вклад жестких процессов.
SIBYLL 2.1, QGSJET описывают взаимодействие кварков и глюонов как рождение одномерных релятивистских струн (трубои цветного тока) с концами, прикрепленными к валентному кварку (дикварку) из мишени и налетающей частицы; когда расстояние между кварками превышает критическое, струна рвется, образуя пару кварк-антикварк
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 23А. Морозова, Электронные нейтрино 23
Вклады каоновв спектры электронных нейтрино
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 2424
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 25
Результаты
• Рассчитаны вклады в потоки электронных нейтрино от трехчастичных полулептонных мод распада заряженных и нейтральных К-мезонов, рождающихся в широких атмосферных ливнях, порожденных космическими лучами
• Показано, что распад короткоживущего нейтрального каона при энергиях выше 100 ТэВ дает более 1/3 потока атмосферных электронных нейтрино (без учета прямых нейтрино)
• Учет генерации К-мезонов при взаимодействии пионов с ядрами, приводит к увеличению потока на (5-7) % в интервале энергий 102 -104 ГэВ.
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 2626
Адронный каскад в атмосфере
0S eK e
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 2727
ГэВEсмGeV
E
ГэВEсмGeV
EN E5238
524.0
36
10,1
107.0
10,1
10.3
)(
Регистрация мюонных нейтрино
кмnТэВ водаNN41 104.2)100(
XN )()( (СС)
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 28А. Морозова, Электронные нейтрино 28
Рассеяние нейтрино на нуклонах
v N X
Процессы с нейтральными токами (NC):
e N e X
N X e eN X
Процессы с заряженными токами (СС):
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 2929
Частица Время жизни(s) Масса(MeV)
493,6
497,6
497,6
105,6
3eK
03SeK
03LeK
3e
81,24 10
85,12 10
100,90 10
62,19 10
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 3030
Частица Мода распада Вероятность распада(%)
Критическая энергия
5,04 890 ГэВ
40,55 210 ГэВ
0,07 120 ТэВ
100 1,03 ГэВ
3eK
03SeK
03LeK
( ) ( )e ee
0 ( )e ee
( )e ee
( )e ee
3e
Источники электронных нейтрино
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 31
Энергетические спектры атмосферных и астрофизических нейтрино (иллюстрация)
( 1)
( 1)
( 2 )
1
1 /
,
,
d crf
crf
crf
w EE E
E E E
E E E
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 32
Critical energy for a meson decay in the Earth’s atmosphere
( 1)
( 1)
( 2 )
1
1 /
,
,
d crf
crf
crf
w EE
E E
E E
2dec
decdec
,( , )
K
K
dh dw m cdw
dh h c E
crdec 0 ( )
ln cosK K
K
dw m H
d h E E
2cr f 0f
f
/ cos( )
m c H
c
An illustration
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 33
The energy spectra of atmospheric and astrophysical neutrinos (illustration)
( 1)
( 1)
( 2 )
1
1 /
,
,
d crf
crf
crf
w EE E
E E E
E E E
cr 20( ) / ( cos )K K KE m c H c
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 34
The contributions of kaon spectra in electron neutrinos
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 35
Motivation (Target setting)• Main sources of the atmospheric at high
energies is semileptonic decays of kaons
charged and neutral kaons
• At energies above 10 TeV the rare decay mode of the
short-lived K0-meson, , can
contribute significantly to the neutrino flux
(V.Naumov,hep-ph/0201310; T. Sinegovskaya, PhD thesis,1999)
• A contrubution of K-mesons production in the reaction
of pion-nuclei interactions
e e
0 0, ,L SK K K
A K X
0 ( )S e eK e
It is also of the interest how much the reaction of pion-nuclei interactions contrubutes to the fluxe e
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 36
Astrophysical neutrinos and AN background
• The main event in neutrino astrophysics at last two
years is the IceCube detection of 37 high-energy
neutrino events from astrophysical sources (expected
~ 15 events from the AM, AN)
• Atmospheric neutrinos are a background for
astrophysical neutrinos which one needs know
• Most uncertainties in the calculations of the high-
energy background are due to difference in hadronic
interaction models predictions of the cross sections
of the strange particles production
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 37
Motivation • Main sources of the atmospheric at high
energies are semileptonic decays of kaons
charged and neutral kaons
• At energies above 10 TeV the rare decay mode of the
short-lived K0-meson, , can
contribute significantly to the neutrino flux
(V.Naumov,hep-ph/0201310; T. Sinegovskaya, PhD thesis,1999)
e e
0 0, ,L SK K K
A K X
0 ( )S e eK e
• It is also of the interest, how much the pion-nuclei interactions contrbutes to the fluxe e
15th Baikal Summer School Anna Morozova, Atmospheric neutrinos 38
Models of hadron-nuclear interactions at high energies
QGSJET-II-03 (Quark Gluon String model with JETs) – the extension of the model of quark-gluon strings (MQGS), including hadron jets - the contribution of hard processes.
SIBYLL 2.1 - describe the birth of quarks and gluons through a one-dimensional relativistic string (tube current color) with the ends attached to the valence quark (diquark) from the target and incident particle; when the distance between the quarks exceeds a critical value, the string breaks, giving rise to a pair of quark-antiquark .
SIBYLL 2.1 - the model with the inclusion of mini-jets (semi-hardd processes) is based on approximates QCD and soft and hard processes