The local interstellar spectrum (LIS) of cosmic-ray (CR) electrons for the energy range 1 MeV to 1 TeV is derived using the most recent experimental results combined with the state-of-the-art models ...for CR propagation in the Galaxy and in the heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for model-data comparison. The optimized HelMod parameters are then used to adjust GALPROP parameters to predict a refined LIS with the procedure repeated subject to a convergence criterion. The parameter optimization uses an extensive data set of proton spectra from 1997 to 2015. The proposed CR electron LIS accommodates both the low-energy interstellar spectra measured by Voyager 1 as well as the high-energy observations by PAMELA and AMS-02 that are made deep in the heliosphere; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The interstellar and heliospheric propagation parameters derived in this study agree well with our earlier results for CR protons, helium nuclei, and anti-protons propagation and LIS obtained in the same framework.
Local interstellar spectra (LIS) for protons, helium, and antiprotons are built using the most recent experimental results combined with state-of-the-art models for propagation in the Galaxy and ...heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of cosmic-ray (CR) species at different modulation levels and at both polarities of the solar magnetic field. To do so in a self-consistent way, an iterative procedure was developed, where the GALPROP LIS output is fed into HelMod, providing modulated spectra for specific time periods of selected experiments to compare with the data; the HelMod parameter optimization is performed at this stage and looped back to adjust the LIS using the new GALPROP run. The parameters were tuned with the maximum likelihood procedure using an extensive data set of proton spectra from 1997 to 2015. The proposed LIS accommodate both the low-energy interstellar CR spectra measured by Voyager 1 and the high-energy observations by BESS, Pamela, AMS-01, and AMS-02 made from the balloons and near-Earth payloads; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The found solution is in a good agreement with proton, helium, and antiproton data by AMS-02, BESS, and PAMELA in the whole energy range.
We compute the gravitational corrections to the running of couplings in a scalar-fermion system, using the Wilsonian approach. Our discussion is relevant for symmetric as well as for broken scalar ...phases. We find that the Yukawa and quartic scalar couplings become irrelevant at the Gaussian fixed point.
We employ perturbative renormalization group and ε-expansion to study multicritical single-scalar field theories with higher derivative kinetic terms of the form ϕ(−□)kϕ. We focus on those with a ...Z2-symmetric critical point which are characterized by an upper critical dimension dc=2nk/(n−1) accumulating at even integers. We distinguish two types of theories depending on whether or not the numbers k and n−1 are relatively prime. When they are, the critical theory involves a marginal powerlike interaction ϕ2n and the deformations admit a derivative expansion that at leading order involves only the potential. In this case we present the beta functional of the potential and use this to calculate some anomalous dimensions and operator product expansion coefficients. These confirm some conformal field theory data obtained using conformal-block techniques, while giving new results. In the second case where k and n−1 have a common divisor, the theories show a much richer structure induced by the presence of marginal derivative operators at criticality. We study the case k=2 with odd values of n, which fall in the second class, and calculate the functional flows and spectrum. These theories have a phase diagram characterized at leading order in ε by four fixed points which apart from the Gaussian UV fixed point include an IR fixed point with a purely derivative interaction.
We compute the crossover exponents of all quadratic and cubic deformations of critical field theories with permutation symmetry
S
q
in
d
=
6
-
ϵ
(Landau–Potts field theories) and
d
=
4
-
ϵ
...(hypertetrahedral models) up to three loops. We use our results to determine the
ϵ
-expansion of the fractal dimension of critical clusters in the most interesting cases, which include spanning trees and forests (
q
→
0
), and bond percolations (
q
→
1
). We also explicitly verify several expected degeneracies in the spectrum of relevant operators for natural values of
q
upon analytic continuation, which are linked to logarithmic corrections of CFT correlators, and use the
ϵ
-expansion to determine the universal coefficients of such logarithms.
Local interstellar spectra (LIS) of secondary cosmic-ray (CR) nuclei, lithium, beryllium, boron, and partially secondary nitrogen, are derived in the rigidity range from 10 MV to ∼200 TV using the ...most recent experimental results combined with state-of-the-art models for CR propagation in the Galaxy and in the heliosphere. The lithium spectrum appears somewhat flatter at high energies compared to other secondary species, which may imply a primary lithium component. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of CR species at different modulation levels, and at both polarities of the solar magnetic field. An iterative maximum-likelihood method is developed that uses GALPROP-predicted LIS as input to HelMod, which provides the modulated spectra for specific time periods of the selected experiments for the model-data comparison. The proposed LIS accommodates the low-energy interstellar spectra measured by Voyager 1, the High Energy Astrophysics Observatory-3 (HEAO-3), and the Cosmic Ray Isotope Spectrometer on board of the Advanced Composition Explorer (ACE/CRIS), as well as the high-energy observations by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), Alpha Magnetic Spectrometer-02 (AMS-02), and earlier experiments that are made deep in the heliosphere. The interstellar and heliospheric propagation parameters derived in this study are consistent with our earlier results for propagation of CR protons, helium, carbon, oxygen, antiprotons, and electrons.
Abstract
Composition and spectra of Galactic cosmic rays (CRs) are vital for studies of high-energy processes in a variety of environments and on different scales, for interpretation of
γ
-ray and ...microwave observations, for disentangling possible signatures of new phenomena, and for understanding of our local Galactic neighborhood. Since its launch, AMS-02 has delivered outstanding-quality measurements of the spectra of
,
, and nuclei:
1
H–
8
O,
10
Ne,
12
Mg,
14
Si. These measurements resulted in a number of breakthroughs; however, spectra of heavier nuclei and especially low-abundance nuclei are not expected until later in the mission. Meanwhile, a comparison of published AMS-02 results with earlier data from HEAO-3-C2 indicates that HEAO-3-C2 data may be affected by undocumented systematic errors. Utilizing such data to compensate for the lack of AMS-02 measurements could result in significant errors. In this paper we show that
a fraction
of HEAO-3-C2 data
match
available AMS-02 measurements quite well and can be used together with Voyager 1 and ACE-CRIS data to make
predictions
for the local interstellar spectra (LIS) of nuclei that are not yet released by AMS-02. We are also updating our already-published LIS to provide a complete set from
1
H–
28
Ni in the energy range from 1 MeV nucleon
−1
to ∼100–500 TeV nucleon
−1
, thus covering 8–9 orders of magnitude in energy. Our calculations employ the G
al
P
rop
–H
el
M
od
framework, which has proved to be a reliable tool in deriving the LIS of CR
,
e
−
, and nuclei
1
H–
8
O.
We adopt a combination of analytical and numerical methods to study the renormalization group flow of the most general field theory with quartic interaction in d = 4 − ε with N = 3 and N = 4 scalars. ...For N = 3 , we find that it admits only three nondecomposable critical points: the Wilson-Fisher with O ( 3 ) symmetry, the cubic with H3 = ( Z2 )3 ⋊ S3 symmetry, and the biconical with O ( 2 ) × Z2. For N = 4 , our analysis reveals the existence of new nontrivial solutions with discrete symmetries and with up to three distinct field anomalous dimensions.
Within the functional renormalization group approach we study the effective quantum field theory of Einstein gravity and one self-interacting scalar coupled to N(f) Dirac fermions. We include in our ...analysis the matter anomalous dimensions induced by all the interactions and analyze the highly nonlinear beta functions determining the renormalization flow. We find the existence of a nontrivial fixed point structure both for the gravity and the matter sector, besides the usual Gaussian matter one. This suggests that asymptotic safety could be realized in the gravitational sector and in the standard model. Nontriviality in the Higgs sector might involve gravitational interactions.
We study the Blume-Capel universality class in d=103−ε dimensions. The renormalization group flow is extracted by looking at poles in fractional dimension of three loop diagrams using MS¯. The theory ...is the only nontrivial universality class which admits an expansion to three dimensions with ε=13<1. We compute the relevant scaling exponents and estimate some of the operator product expansion coefficients to the leading order. Our findings agree with and complement conformal field theory results. Finally we discuss a family of nonunitary multicritical models which includes the Lee-Yang and Blume-Capel classes as special cases.
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