اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدA new evaluation of the antiproton production cross section for cosmic ray studies
90
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Theoretical predictions for the cosmic antiproton spectrum currently fall short of the corresponding experimental level of accuracy. Among the main sources of uncertainty are the antiproton production cross sections in cosmic ray inelastic interactions. We analyse existing data on antiproton production in $pp$ scattering, including for the first time the measurements performed by the NA49 Collaboration. We compute the antiproton spectrum finding that in the energy range where data are available (antiproton energies of about 4-550 GeV) different approaches lead to almost equivalent results, with an uncertainty of 10-20%. Extrapolations outside this region lead to different estimates, with the uncertainties reaching the 50% level around $1$ TeV, degrading the diagnostic power of the antiproton channel at those energies. We also comment on the uncertainties in the antiproton production source term coming from nuclei heavier than protons and from neutrons produced in $pp$ scatterings, and point out the need for dedicated experimental campaigns for all processes involving antiproton production in collisions of light nuclei.
قيم البحث
اقرأ أيضاً
In this work we show that the excess of antiprotons in the range $E_{K}=10-20 ~GeV$ reported by several groups in the analysis of the AMS-02 Collaboration data, can be explained by the production of antiprotons in the annihilation of dark matter with
a $(1,0)oplus (0,1)$ space-time structure (tensor dark matter). First, we calculate the proton and antiproton flux from conventional mechanisms and fit our results to the AMS-02 data, confirming the antiproton excess. Then we calculate the antiproton production in the annihilation of tensor dark matter. For the window $Min [62.470,62.505] ~ GeV$ to which the measured relic density, XENO1T results and the gamma ray excess from the galactic center constrain the values of the tensor dark matter mass, we find sizable contributions of antiprotons in the excess region from the annihilation into $bar{b}b$ and smaller contributions from the $bar{c}c$ channel. We fit our results to the AMS-02 data, finding an improvement of the fit for these values of $M$.
A dramatic increase in the accuracy and statistics of space-borne cosmic ray (CR) measurements has yielded several breakthroughs over the last several years. The most puzzling is the rise in the positron fraction above ~10 GeV over the predictions of
the propagation models assuming pure secondary production. The accuracy of the antiproton production cross section is critical for astrophysical applications and searches for new physics since antiprotons in CRs seem to hold the keys to many puzzles including the origin of those excess positrons. However, model calculations of antiproton production in CR interactions with interstellar gas are often employing parameterizations that are out of date or are using outdated physical concepts. That may lead to an incorrect interpretation of antiproton data which could have broad consequences for other areas of astrophysics. In this work, we calculate antiproton production in pp-, pA-, and AA-interactions using EPOS-LHC and QGSJET-II-04, two of the most advanced Monte Carlo (MC) generators tuned to numerous accelerator data including those from the Large Hadron Collider (LHC). We show that the antiproton yields obtained with these MC generators differ by up to an order of magnitude from yields of parameterizations commonly used in astrophysics.
The CoGeNT experiment, dedicated to direct detection of dark matter, has recently released excess events that could be interpreted as elastic collisions of $sim$10 GeV dark matter particles, which might simultaneously explain the still mysterious DAM
A/LIBRA modulation signals, while in conflict with results from other experiments such as CDMS, XENON-100 and SIMPLE. It was shown that 5-15 GeV singlino-like dark matter candidates arising in singlet extensions of minimal supersymmetric scenarios can fit these data; annihilation then mostly proceeds into light singlet-dominated Higgs (pseudo)scalar fields. We develop an effective Lagrangian approach to confront these models with the existing data on cosmic-ray antiprotons, including the latest PAMELA data. Focusing on a parameter space consistent with the CoGeNT region, we show that the predicted antiproton flux is generically in tension with the data whenever the produced (pseudo)scalars can decay into quarks energetic enough to produce antiprotons, provided the annihilation S-wave is significant at freeze out in the early universe. In this regime, a bound on the singlino annihilation cross section is obtained, $sigvlesssim 10^{-26},{rm cm^3/s}$, assuming a dynamically constrained halo density profile with a local value of $rho_odot = 0.4,{rm GeV/cm^3}$. Finally, we provide indications on how PAMELA or AMS-02 could further constrain or detect those configurations producing antiprotons which are not yet excluded.
We study the production of exotic millicharged particles (MCPs) from cosmic ray-atmosphere collisions which constitutes a permanent MCP production source for all terrestrial experiments Our calculation of the MCP flux can be used to reinterpret exist
ing limits from experiments such as MACRO and Majorana on an ambient flux of ionizing particles. Large-scale underground neutrino detectors are particularly favorable targets for the resulting MCPs. Using available data from the Super-K experiment, we set new limits on MCPs, which are the best in sensitivity reach for the mass range $0.1 lesssim m_{chi} lesssim 0.5$ GeV, and which are competitive with accelerator-based searches for masses up to 1.5 GeV. Applying these constraints to models where a sub-dominant component of dark matter (DM) is fractionally charged allows us to probe parts of the parameter space that are challenging for conventional direct-detection DM experiments, independently of any assumptions about the DM abundance. These results can be further improved with the next generation of large-scale neutrino detectors.
In this contribution the matrix element generator AMEGIC++ will be presented. It automatically generates Feynman diagrams, helicity amplitudes, and suitable phase space mappings for processes involving multi-particle final states within the Standard Model and some of its popular extensions.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
