Search

The FASER experiment at the LHC is designed to search for light, weakly-interacting particles produced in proton-proton collisions at the ATLAS interaction point that travel in the far-forward direction. The first results from a search for dark photons decaying to an electron-positron pair, using a dataset corresponding to an integrated luminosity of 27.0 fb−1 collected at centre-of-mass energy s=13.6 TeV in 2022 in LHC Run 3, are presented. No events are seen in an almost background-free analysis, yielding world-leading constraints on dark photons with couplings ϵ∼2×10−5−1×10−4 and masses ∼17 MeV−70 MeV. The analysis is also used to probe the parameter space of a massive gauge boson from a U(1)B−L model, with couplings gB−L∼5×10−6−2×10−5 and masses ∼15 MeV−40 MeV excluded for the first time.

Abstract Background “Kratom” commonly refers to the botanical Mitragyna speciosa, native to Southeast Asia, which is increasingly used globally for its unique pharmacological effects. Motives for using the whole plant material or kratom-derived products include self-management of pain, mental health disorders, symptoms related to substance use disorders, and/or to increase energy. In the United States, kratom products have varying alkaloid content, potencies, and marketing profiles. There is little regulatory oversight over kratom, as it is currently not approved as a dietary supplement by the Food and Drug Administration. This results in substantial variability in labeling of kratom products and the product information provided to consumers. Methods In January 2023, we evaluated the American Kratom Association’s Good Manufacturing Practices (GMP) qualified vendors’ websites (n = 42) using the well-established and validated DISCERN instrument to examine the quality of health information provided to consumers. DISCERN contains 15 five-point Likert-scale questions on specific criteria, with the highest possible score being 75, indicating that all the DISCERN criteria have been fulfilled by the website (i.e., the highest quality information is provided to consumers). Results The mean DISCERN score for all evaluated online kratom vendors was 32.72 (SD = 6.69; score range 18.00–43.76). Overall, vendors scored higher on DISCERN questions assessing the website’s reliability, as vendors typically provided clear information for consumers about product availability, purchasing, shipping, etc. On average, vendors scored poorly on the DISCERN section pertaining to the quality of the health information provided. Information on kratom’s potential risks and benefits was particularly insufficient. Conclusions Consumers require high quality information in order to make informed decisions concerning use, which entails disclosure of known risks and potential benefits. The online kratom vendors evaluated in this study should consider enhancing the quality of health information provided, especially information regarding kratom’s risks and benefits. Further, consumers should be made aware of current knowledge gaps related to kratom’s effects. Clinicians must also be aware of the lack of evidence-based information available to their patients who use kratom or are interested in using kratom products, in order to facilitate educational discussions with them.

MR-guided radiotherapy on hybrid MR-Linacs exploits the excellent soft-tissue contrast of MRI to deliver daily adaptive precision radiotherapy. Geometric fidelity and long-term stability of MRI components are essential, but their longitudinal performance under daily exposure to scattered ionizing radiation is unknown. We report on longitudinal stability of periodic MRI QA on eight clinical 1.5T MR-Linac systems. We provided measurement instructions for periodic MRI QA and received data from seven different centers within the Elekta MR-Linac consortium, which contributed data over acquisition periods ranging from 3–24 months. We tested B0 and B1 homogeneity using a 37 cm diameter cylindrical phantom, which was measured monthly in axial orientation, supplemented by quarterly sagittal and coronal acquisitions. We report average, standard deviation and peak-to-peak variation (99th-1st percentile) within a region of interest (ROI) of 35 cm diameter. Dependence of B0 on the gantry angle and gradient non-linearity were tested quarterly. We analyzed the longitudinal stability of selected metrics of the vendor-provided periodic image quality tests. We found high temporal stability of B0 and B1 measurements and good agreement between different MR-Linac systems. For all measurements, the standard deviation of B0 within the analyzed ROI was below 0.66/0.33/0.33 ppm for axial/sagittal/coronal orientation. The average standard deviation of the ratio between actual and nominal flip angle was 0.022/0.100/0.088 for axial/sagittal/coronal orientation. Systems exhibited distinctively different gantry angle dependencies of B0, with sensitivities of B0 to the gantry angle differing by factors of up to two between systems. Gradient non-linearity analysis yielded average radii of 172 and 242 mm for which 98% of the phantom markers had deviations below 1 and 2 mm, respectively. All analyzed periodic image quality tests were passed, but major events including a body coil replacement and ramp down were apparent in the time series. Overall we found very similar performance of the tested systems and our results could inform the implementation of MR imaging QA for MR-Linacs. While we found differences of the gantry angle dependence of B0 between systems, the high temporal stability found for all tests is a foundation for stereotactic radiotherapy and multi-center clinical trials involving quantitative MRI.

Abstract Neutrinos are copiously produced at particle colliders, but no collider neutrino has ever been detected. Colliders produce both neutrinos and anti-neutrinos of all flavors at very high energies, and they are therefore highly complementary to those from other sources. FASER, the Forward Search Experiment at the LHC, is ideally located to provide the first detection and study of collider neutrinos. We investigate the prospects for neutrino studies with FASER$$\nu $$ ν , a proposed component of FASER, consisting of emulsion films interleaved with tungsten plates with a total target mass of 1.2 t, to be placed on-axis at the front of FASER. We estimate the neutrino fluxes and interaction rates, describe the FASER$$\nu $$ ν detector, and analyze the characteristics of the signals and primary backgrounds. For an integrated luminosity of $$150~\text {fb}^{-1}$$ 150fb-1 to be collected during Run 3 of the 14 TeV LHC in 2021–23, approximately 1300 electron neutrinos, 20,000 muon neutrinos, and 20 tau neutrinos will interact in FASER$$\nu $$ ν , with mean energies of 600 GeV to 1 TeV. With such rates and energies, FASER will measure neutrino cross sections at energies where they are currently unconstrained, will bound models of forward particle production, and could open a new window on physics beyond the standard model.

The “Laser-hybrid Accelerator for Radiobiological Applications,” LhARA, is conceived as a novel, flexible facility dedicated to the study of radiobiology. The technologies demonstrated in LhARA, which have wide application, will be developed to allow particle-beam therapy to be delivered in a new regimen, combining a variety of ion species in a single treatment fraction and exploiting ultra-high dose rates. LhARA will be a hybrid accelerator system in which laser interactions drive the creation of a large flux of protons or light ions that are captured using a plasma (Gabor) lens and formed into a beam. The laser-driven source allows protons and ions to be captured at energies significantly above those that pertain in conventional facilities, thus evading the current space-charge limit on the instantaneous dose rate that can be delivered. The laser-hybrid approach, therefore, will allow the radiobiology that determines the response of tissue to ionizing radiation to be studied with protons and light ions using a wide variety of time structures, spectral distributions, and spatial configurations at instantaneous dose rates up to and significantly beyond the ultra-high dose-rate “FLASH” regime. It is proposed that LhARA be developed in two stages. In the first stage, a programme of in vitro radiobiology will be served with proton beams with energies between 10 and 15 MeV. In stage two, the beam will be accelerated using a fixed-field alternating-gradient accelerator (FFA). This will allow experiments to be carried out in vitro and in vivo with proton beam energies of up to 127 MeV. In addition, ion beams with energies up to 33.4 MeV per nucleon will be available for in vitro and in vivo experiments. This paper presents the conceptual design for LhARA and the R&D programme by which the LhARA consortium seeks to establish the facility.

The enlargement of the European Union in 2004 gave rise to moral panics concerning the likelihood of mass migration from the new eastern European member states to established member states in the west. A great deal of social and political science research has examined the ongoing impact of the enlargement, but there remains a gap in the literature regarding the ways in which members of ‘receiving’ populations reacted to these changes. The present paper reports findings from a qualitative interview study of 14-16 year-olds conducted in northern England. It focuses on how migrants from one particular country – Poland – were constructed by participants. Drawing on previous analyses of immigration and racist discourse, the study points to some ways in which Polish migrants and migration were constructed, and how complaints against ‘the Polish’ were formulated. The analysis focusses on four key issues: employment and the economy; language and culture; threat and intimidation; and physical stereotyping. It is suggested that constructions of ‘the Polish’ draw on the tropes of both ‘old’ and ‘new’ racism, and that attention to the use of deixical ingroup referents (‘us’, ‘we’, ‘our’) in contrast to the explicit labelling of the outgroup (‘the Polish’) can be understood in terms of the requirement to present complaints concerning migrant groups via appeals to assumed universal standards of behaviour and civility.