Conceptual design report for the LUXE experiment Abramowicz, H.; Acosta, U.; Altarelli, M. ...
The European physical journal. ST, Special topics,
2021, Letnik:
230, Številka:
11
Journal Article
Recenzirano
Odprti dostop
This Conceptual Design Report describes LUXE (Laser Und XFEL Experiment), an experimental campaign that aims to combine the high-quality and high-energy electron beam of the European XFEL with a ...powerful laser to explore the uncharted terrain of quantum electrodynamics characterised by both high energy and high intensity. We will reach this hitherto inaccessible regime of quantum physics by analysing high-energy electron-photon and photon-photon interactions in the extreme environment provided by an intense laser focus. The physics background and its relevance are presented in the science case which in turn leads to, and justifies, the ensuing plan for all aspects of the experiment: Our choice of experimental parameters allows (i) field strengths to be probed where the coupling to charges becomes non-perturbative and (ii) a precision to be achieved that permits a detailed comparison of the measured data with calculations. In addition, the high photon flux predicted will enable a sensitive search for new physics beyond the Standard Model. The initial phase of the experiment will employ an existing 40 TW laser, whereas the second phase will utilise an upgraded laser power of 350 TW. All expectations regarding the performance of the experimental set-up as well as the expected physics results are based on detailed numerical simulations throughout.
We propose a novel way to search for feebly interacting massive particles, exploiting two properties of systems involving collisions between high energy electrons and intense laser pulses. The first ...property is that the electron-laser collision results in a large flux of hard photons, as the laser behaves effectively as a thick medium. The second property is that the emitted photons free-stream inside the laser and thus for them the laser behaves effectively as a very thin medium. Combining these two features implies that the electron-intense-laser collision is an apparatus, which can efficiently convert O(10 GeV) electrons to a large flux of hard, collinear photons. The photons are directed onto a solid dump in which feebly interacting massive particles may be produced. With the much smaller backgrounds induced by the photon beam compared to those expected in electron- or proton-beam dump experiments and combined with a relatively shorter dump used here, the sensitivity to short lifetimes is unparalleled. We denote this novel apparatus as "optical dump"or NPOD (new physics search with optical dump). The proposed LUXE experiment at the European XFEL has all the basic required ingredients to realize this experimental concept for the first time. Moreover, the NPOD extension of LUXE is essentially parasitic to the main experiment and thus, practically it does not have any bearing on its main program. We discuss how the NPOD concept can be realized in practice by adding a detector after the last physical dump of the experiment to reconstruct the two-photon decay of a new spin-0 particle. We show that even with a relatively short dump, the search can still be background-free. Remarkably, even with a few days of data taking with a 40 TW laser corresponding to its initial run, LUXE-NPOD will be able to probe an uncharted territory of models with pseudoscalars and scalars. Furthermore, with a 350 TW laser of the main run, LUXE-NPOD will have a unique reach for these models. In particular it can probe natural scalar theories for masses above 100 MeV. We note that the new NPOD concept may be ported to other existing or future facilities worldwide, including, e.g., future lepton colliders.
We evaluated the oral calcium-loading test (OCLT) in diagnosing normocalcemic primary hyperparathyroidism. Calcium and PTH levels were measured before, 60, 120 and 180 min after oral 1 g of calcium ...gluconolactate administration in 102 consecutive females with high circulating PTH levels, and 25 controls. Patients were classified as follows: Group A, patients with a parathyroid adenoma identified by two imaging modalities. Sub-Group AO, hyperparathyroid patients no.=13, mean age 59 yr (SD=10) evaluated prior to parathyroidectomy. Sub-Group AH, non-operated hypercalcemic patients no.=29, age 63 yr (SD=11). Sub-Group AN, normocalcemic non-operated women no.=14, age 59 yr (SD=8). Group B, normocalcemic individuals no.=46, age 58 yr (SD=11) with negative parathyroid imaging. Group C, control patients no.= 25, age 56 yr (SD=12). The concentrations of calcium and PTH overlapped in the normocalcemic groups during the OCLT. Product P, defined as circulating PTH nadir (pg/ml) x peak calcium concentration (mg/dl), better discriminated Sub-Group AN from Group B, AUC=0.98 (95% CI 0.95, 1.00) than did Ratio R, defined as relative PTH decline/relative calcium increment, AUC= 0.86 (95%CI 0.73, 0.99). Assuming normal threshold of Product P and Ratio R at 260 and 17 respectively, the combined parameters diagnose normocalcemic hyperparathyroid patients with 100% sensitivity and 87% specificity.
This Technical Design Report presents a detailed description of all aspects of the LUXE (Laser Und XFEL Experiment), an experiment that will combine the high-quality and high-energy electron beam of ...the European XFEL with a high-intensity laser, to explore the uncharted terrain of strong-field quantum electrodynamics characterised by both high energy and high intensity, reaching the Schwinger field and beyond. The further implications for the search of physics beyond the Standard Model are also discussed.
One hundred and twenty-nine patients with papillary thyroid carcinoma were treated with radioiodine (I-131) and followed up in our department between the years 1992 and 2000. Thirty-three patients ...(25.6%) had distant metastases (mean follow-up time was 3.12 +/- 2.9 years). The incidence of distant metastases among patients with papillary carcinoma was higher in our group in comparison with most published studies. The most common sites for distant metastases were the lungs and mediastinum. In 32 of the 33 patients distant metastases were found in those sites. We characterized two main patterns of I-131 uptake in lung metastases: in the first there was diffuse lung uptake and in the second there were focal lesions. Bone metastases were only found in one patient. Distant metastases were found in 38.7% of males as compared to 21.4% of females. The age of the male patients with distant metastases was significantly higher than the age of the other patients (mean age 52.8 years, p = 0.099). There was no significant association between distant metastases and advanced age. Most cases of distant metastases in females (81%) were diagnosed at the time of the primary diagnosis as compared to less than half (42%) in males. Sixteen patients with distant metastases underwent cervical lymph node dissection. In 15 patients (94%) cervical lymph node metastases were found. It was found that 39.4% of the patients with distant metastases were born in Israel and 30.3% were born in the Soviet Union. The percentage of the patients with distant metastases, who came to Israel from the Soviet Union after the nuclear accident in Chernobyl (1986), was found to be significantly higher then their relative number in the Israeli population and higher then their relative number in the hospitalized patient population in the years of the study (24.2% as compared to 9% and 8.1% respectively). The survival rate of patients with distant metastases was 97% and for patients without metastases the rate was 100%.
PDF
