ATHENA detector proposal — a totally hermetic electron nucleus apparatus proposed for IP6 at the Electron-Ion Collider

ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges

Effect of CD8+ T-cell depletion on bronchial hyper-responsiveness and inflammation in sensitized and allergen-exposed Brown–Norway rats

We examined the role of CD8+ T cells in a Brown–Norway rat model of asthma, using a monoclonal antibody to deplete CD8+ T cells. Ovalbumin (OA)-sensitized animals were given anti-CD8 antibody (0·5 mg/rat) intravenously 1 week prior to exposure to 1% OA aerosol and were studied 18–24 hr after aerosol exposure. Following administration of anti-CD8 antibody, CD8+ cells were reduced to <1% of total lymphocytes in whole blood and in spleen. In sensitized animals, OA exposure induced bronchial hyper-responsiveness (BHR), accumulation of eosinophils, lymphocytes and neutrophils in bronchoalveolar lavage (BAL) fluid, and also an increase in tissue eosinophils and CD2+, CD4+ and CD8+T cells in airways. Anti-CD8 antibody caused a further increase in allergen-induced BHR (P < 0·03, compared with sham-treated animals), together with a significant increase in eosinophil number in BAL fluid (P < 0·05). While CD2+ and CD4+ T cells in airways were not affected by anti-CD8 treatment, the level of CD8+ T cells was significantly reduced in sensitized, saline-exposed animals (P < 0·04, compared with sham-treated rats), and sensitized and OA-challenged rats (P < 0·002, compared with sham-treated rats). Using reverse transcription–polymerase chain reaction, an increase of T helper (Th)2 cytokine [interleukin (IL)-4 and IL-5], and also of Th1 cytokine [interferon-γ (IFN-γ) and IL-2], mRNA in the lung of sensitized and OA-exposed animals was found; after CD8+ T-cell depletion, Th1 cytokine expression was significantly reduced (P < 0·02), while Th2 cytokine expression was unchanged. CD8+ T cells have a protective role in allergen-induced BHR and eosinophilic inflammation, probably through activation of the Th1 cytokine response

Nonperturbative transverse-momentum-dependent effects in dihadron and direct photon-hadron angular correlations in p+pp+p collisions at s=200\sqrt{s}=200 GeV

International audienceDihadron and isolated direct photon-hadron angular correlations are measured in p+p collisions at s=200  GeV. The correlations are sensitive to nonperturbative initial-state and final-state transverse momenta kT and jT in the azimuthal nearly back-to-back region Δϕ∼π. To have sensitivity to small transverse momentum scales, nonperturbative momentum widths of pout, the out-of-plane transverse-momentum component perpendicular to the trigger particle, are measured. In this region, the evolution of pout can be studied when several different hard scales are measured. These widths are used to investigate possible effects from transverse-momentum-dependent factorization breaking. When accounting for the longitudinal-momentum fraction of the away-side hadron with respect to the near-side trigger particle, the widths are found to increase with the hard scale; this is qualitatively similar to the observed behavior in Drell-Yan and semi-inclusive deep-inelastic scattering interactions, where factorization is predicted to hold. The momentum widths are also studied as a function of center-of-mass energy by comparing to previous measurements at s=510  GeV. The nonperturbative jet widths also appear to increase with s at a similar xT, which is qualitatively consistent to similar measurements in Drell-Yan interactions. Future detailed global comparisons between measurements of processes where transverse-momentum-dependent factorization is predicted to hold and be broken will provide further insight into the role of color in hadronic interactions