Context.
The vertical diffusive halo size of the Galaxy,
L
, is a key parameter for dark matter indirect searches. It can be better determined thanks to recent AMS-02 data.
Aims.
We set constraints ...on
L
from Be/B and
10
Be/Be data, and we performed a consistency check with positron data. We detail the dependence of Be/B and
10
Be/Be on
L
and forecast on which energy range better data would be helpful for future
L
improvements.
Methods.
We used
USINE V3.5
for the propagation of nuclei, and e
+
were calculated with the pinching method.
Results.
The current AMS-02 Be/B (∼3% precision) and ACE-CRIS
10
Be/Be (∼10% precision) data bring similar and consistent constraints on
L
. The AMS-02 Be/B data alone constrain
L
= 5
−2
+3
kpc at a 68% confidence level (spanning different benchmark transport configurations), a range for which most models do not overproduce positrons. Future experiments need to deliver percent-level accuracy on
10
Be/
9
Be anywhere below 10 GV to further constrain
L
.
Conclusions.
Forthcoming AMS-02, HELIX, and PAMELA
10
Be/
9
Be results will further test and possibly tighten the limits derived here. Elemental ratios involving radioactive species with different lifetimes (e.g. Al/Mg and Cl/Ar) are also awaited to provide complementary and robuster constraints.
Abstract We estimate the efficiency of mitigating the lensing B -mode polarization, the so-called delensing, for the LiteBIRD experiment with multiple external data sets of lensing-mass tracers. The ...current best bound on the tensor-to-scalar ratio, r , is limited by lensing rather than Galactic foregrounds. Delensing will be a critical step to improve sensitivity to r as measurements of r become more and more limited by lensing. In this paper, we extend the analysis of the recent LiteBIRD forecast paper to include multiple mass tracers, i.e., the CMB lensing maps from LiteBIRD and CMB-S4-like experiment, cosmic infrared background, and galaxy number density from Euclid - and LSST-like survey. We find that multi-tracer delensing will further improve the constraint on r by about 20%. In LiteBIRD , the residual Galactic foregrounds also significantly contribute to uncertainties of the B -modes, and delensing becomes more important if the residual foregrounds are further reduced by an improved component separation method.
Abstract We present a study of the impact of a beam far side-lobe lack of knowledge on the measurement of the Cosmic Microwave Background B -mode signal at large scale. Beam far side-lobes induce a ...mismatch in the transfer function of Galactic foregrounds between the dipole and higher multipoles which degrads the performances of component separation methods. This leads to foreground residuals in the CMB map. It is expected to be one of the main source of systematic effects in future CMB polarization observations. Thus, it becomes crucial for all-sky survey missions to take into account the interplays between beam systematic effects and all the data analysis steps. LiteBIRD is the ISAS/JAXA second strategic large-class satellite mission and is dedicated to target the measurement of CMB primordial B modes by reaching a sensitivity on the tensor-to-scalar ratio r of σ ( r ) ≤ 10 -3 assuming r = 0. The primary goal of this paper is to provide the methodology and develop the framework to carry out the end-to-end study of beam far side-lobe effects for a space-borne CMB experiment. We introduce uncertainties in the beam model, and propagate the beam effects through all the steps of the analysis pipeline, most importantly including component separation, up to the cosmological results in the form of a bias δr . As a demonstration of our framework, we derive requirements on the calibration and modeling for the LiteBIRD 's beams under given assumptions on design, simulation, component separation method and allocated error budget. In particular, we assume a parametric method of component separation with no mitigation of the far side-lobes effect at any stage of the analysis pipeline. We show that δr is mostly due to the integrated fractional power difference between the estimated beams and the true beams in the far side-lobes region, with little dependence on the actual shape of the beams, for low enough δr . Under our set of assumptions, in particular considering the specific foreground cleaning method we used, we find that the integrated fractional power in the far side-lobes should be known at the level of ∼ 10 -4 , to achieve the required limit on the bias δr < 1.9 × 10 -5 . The framework and tools developed for this study can be easily adapted to provide requirements under different design, data analysis frameworks and for other future space-borne experiments, such as PICO or CMB-Bharat. We further discuss the limitations of this framework and potential extensions to circumvent them.
Abstract We explore the capability of measuring lensing signals in LiteBIRD full-sky polarization maps. With a 30 arcmin beam width and an impressively low polarization noise of 2.16 μ K-arcmin, ...LiteBIRD will be able to measure the full-sky polarization of the cosmic microwave background (CMB) very precisely. This unique sensitivity also enables the reconstruction of a nearly full-sky lensing map using only polarization data, even considering its limited capability to capture small-scale CMB anisotropies. In this paper, we investigate the ability to construct a full-sky lensing measurement in the presence of Galactic foregrounds, finding that several possible biases from Galactic foregrounds should be negligible after component separation by harmonic-space internal linear combination. We find that the signal-to-noise ratio of the lensing is approximately 40 using only polarization data measured over 80% of the sky. This achievement is comparable to Planck 's recent lensing measurement with both temperature and polarization and represents a four-fold improvement over Planck 's polarization-only lensing measurement. The LiteBIRD lensing map will complement the Planck lensing map and provide several opportunities for cross-correlation science, especially in the northern hemisphere.
Abstract We study the possibility of using the LiteBIRD satellite B -mode survey to constrain models of inflation producing specific features in CMB angular power spectra. We explore a particular ...model example, i.e. spectator axion-SU(2) gauge field inflation. This model can source parity-violating gravitational waves from the amplification of gauge field fluctuations driven by a pseudoscalar “axionlike” field, rolling for a few e-folds during inflation. The sourced gravitational waves can exceed the vacuum contribution at reionization bump scales by about an order of magnitude and can be comparable to the vacuum contribution at recombination bump scales. We argue that a satellite mission with full sky coverage and access to the reionization bump scales is necessary to understand the origin of the primordial gravitational wave signal and distinguish among two production mechanisms: quantum vacuum fluctuations of spacetime and matter sources during inflation. We present the expected constraints on model parameters from LiteBIRD satellite simulations, which complement and expand previous studies in the literature. We find that LiteBIRD will be able to exclude with high significance standard single-field slow-roll models, such as the Starobinsky model, if the true model is the axion-SU(2) model with a feature at CMB scales. We further investigate the possibility of using the parity-violating signature of the model, such as the TB and EB angular power spectra, to disentangle it from the standard single-field slow-roll scenario. We find that most of the discriminating power of LiteBIRD will reside in BB angular power spectra rather than in TB and EB correlations.
The vertical diffusive halo size of the Galaxy, \(L\), is a key parameter for dark matter indirect searches. It can be better determined thanks to recent AMS-02 data. We set constraints on \(L\) from ...Be/B and \(^{10}\)Be/Be data, and we performed a consistency check with positron data. We detail the dependence of Be/B and \(^{10}\)Be/Be on \(L\) and forecast on which energy range better data would be helpful for future \(L\) improvements. We used USINE v3.5 for the propagation of nuclei, and \(e^+\) were calculated with the pinching method of Boudaud et al. (2017). The current AMS-02 Be/B (\(\sim3\%\) precision) and ACE-CRIS \(^{10}\)Be/Be (\(\sim 10\%\) precision) data bring similar and consistent constraints on \(L\). The AMS-02 Be/B data alone constrain \(L=5^{+3}_{-2}\)~kpc at a 68\% confidence level (spanning different benchmark transport configurations), a range for which most models do not overproduce positrons. Future experiments need to deliver percent-level accuracy on \(^{10}\)Be/\(^9\)Be anywhere below 10 GV to further constrain \(L\). Forthcoming AMS-02, HELIX, and PAMELA \(^{10}\)Be/\(^9\)Be results will further test and possibly tighten the limits derived here. Elemental ratios involving radioactive species with different lifetimes (e.g. Al/Mg and Cl/Ar) are also awaited to provide complementary and robuster constraints.
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