Light Dark Matter Search with Ionization Signals in XENON1T

We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22±3) tonne day. Above ∼0.4  keV_{ee}, we observe <1  event/(tonne day keV_{ee}), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses m_{χ} within 3-6  GeV/c^{2}, DM-electron scattering for m_{χ}>30  MeV/c^{2}, and absorption of dark photons and axionlike particles for m_{χ} within 0.186-1  keV/c^{2}.

Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T

Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above ∼5  GeV/c^{2}, but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85  MeV/c^{2} by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Besides the approach of detecting both scintillation and ionization signals, we exploit an approach that uses ionization signals only, which allows for a lower detection threshold. This analysis significantly enhances the sensitivity of XENON1T to light dark matter previously beyond its reach.

Constraining the Spin-Dependent WIMP-Nucleon Cross Sections with XENON1T

We report the first experimental results on spin-dependent elastic weakly interacting massive particle (WIMP) nucleon scattering from the XENON1T dark matter search experiment. The analysis uses the full ton year exposure of XENON1T to constrain the spin-dependent proton-only and neutron-only cases. No significant signal excess is observed, and a profile likelihood ratio analysis is used to set exclusion limits on the WIMP-nucleon interactions. This includes the most stringent constraint to date on the WIMP-neutron cross section, with a minimum of 6.3×10^{-42}  cm^{2} at 30  GeV/c^{2} and 90% confidence level. The results are compared with those from collider searches and used to exclude new parameter space in an isoscalar theory with an axial-vector mediator.

First Results on the Scalar WIMP-Pion Coupling, Using the XENON1T Experiment

We present first results on the scalar coupling of weakly interacting massive particles (WIMPs) to pions from 1  t yr of exposure with the XENON1T experiment. This interaction is generated when the WIMP couples to a virtual pion exchanged between the nucleons in a nucleus. In contrast to most nonrelativistic operators, these pion-exchange currents can be coherently enhanced by the total number of nucleons and therefore may dominate in scenarios where spin-independent WIMP-nucleon interactions are suppressed. Moreover, for natural values of the couplings, they dominate over the spin-dependent channel due to their coherence in the nucleus. Using the signal model of this new WIMP-pion channel, no significant excess is found, leading to an upper limit cross section of 6.4×10^{-46}  cm^{2} (90% confidence level) at 30  GeV/c^{2} WIMP mass.

Dark Matter Search Results from a One Ton-Year Exposure of XENON1T

We report on a search for weakly interacting massive particles (WIMPs) using 278.8 days of data collected with the XENON1T experiment at LNGS. XENON1T utilizes a liquid xenon time projection chamber with a fiducial mass of (1.30±0.01)  ton, resulting in a 1.0 ton yr exposure. The energy region of interest, [1.4,10.6]  keV_{ee} ([4.9,40.9] keV_{nr}), exhibits an ultralow electron recoil background rate of [82_{-3}^{+5}(syst)±3(stat)]  events/(ton yr keV_{ee}). No significant excess over background is found, and a profile likelihood analysis parametrized in spatial and energy dimensions excludes new parameter space for the WIMP-nucleon spin-independent elastic scatter cross section for WIMP masses above 6  GeV/c^{2}, with a minimum of 4.1×10^{-47}  cm^{2} at 30  GeV/c^{2} and a 90% confidence level.

First Dark Matter Search Results from the XENON1T Experiment

We report the first dark matter search results from XENON1T, a ∼2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042±12)-kg fiducial mass and in the [5,40]  keV_{nr} energy range of interest for weakly interacting massive particle (WIMP) dark matter searches, the electronic recoil background was (1.93±0.25)×10^{-4}  events/(kg×day×keV_{ee}), the lowest ever achieved in such a dark matter detector. A profile likelihood analysis shows that the data are consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10  GeV/c^{2}, with a minimum of 7.7×10^{-47}  cm^{2} for 35-GeV/c^{2} WIMPs at 90% C.L.

Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data

We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 yr, from January 2010 to January 2014. A profile likelihood method, which incorporates the stability of the XENON100 detector and the known electronic recoil background model, is used to quantify the significance of periodicity in the time distribution of events. There is a weak modulation signature at a period of 431_{-14}^{+16} day in the low energy region of (2.0-5.8) keV in the single scatter event sample, with a global significance of 1.9σ; however, no other more significant modulation is observed. The significance of an annual modulation signature drops from 2.8σ, from a previous analysis of a subset of this data, to 1.8σ with all data combined. Single scatter events in the low energy region are thus used to exclude the DAMA/LIBRA annual modulation as being due to dark matter electron interactions via axial vector coupling at 5.7σ.

Determination of the separation efficiencies of a single-stage cryogenic distillation setup to remove krypton out of xenon by using a (83m)Kr tracer method

The separation of krypton and xenon is of particular importance for the field of direct dark matter search with liquid xenon detectors. The intrinsic contamination of the xenon with radioactive (85)Kr makes a significant background for these kinds of low count-rate experiments and has to be removed beforehand. This can be achieved by cryogenic distillation, a technique widely used in industry, using the different vapor pressures of krypton and xenon. In this paper, we present an investigation on the separation performance of a single stage distillation system using a radioactive (83m)Kr-tracer method. The separation characteristics under different operation conditions are determined for very low concentrations of krypton in xenon at the level of (83m)Kr/Xe = 1.9 ⋅ 10(-15), demonstrating, that cryogenic distillation in this regime is working. The observed separation is in agreement with the expectation from the different volatilities of krypton and xenon. This cryogenic distillation station is the first step on the way to a multi-stage cryogenic distillation column for the next generation of direct dark matter experiment XENON1T.

Search for Event Rate Modulation in XENON100 Electronic Recoil Data

We have searched for periodic variations of the electronic recoil event rate in the (2-6) keV energy range recorded between February 2011 and March 2012 with the XENON100 detector, adding up to 224.6 live days in total. Following a detailed study to establish the stability of the detector and its background contributions during this run, we performed an unbinned profile likelihood analysis to identify any periodicity up to 500 days. We find a global significance of less than 1σ for all periods, suggesting no statistically significant modulation in the data. While the local significance for an annual modulation is 2.8σ, the analysis of a multiple-scatter control sample and the phase of the modulation disfavor a dark matter interpretation. The DAMA/LIBRA annual modulation interpreted as a dark matter signature with axial-vector coupling of weakly interacting massive particles to electrons is excluded at 4.8σ.

Serum procalcitonin levels in the postmortem diagnosis of sepsis

Procalcitonin is regarded as a valuable marker for sepsis in living persons and even in post-mortem investigations. At the Institute of Legal Medicine, 25 autopsy cases with suspected bacterial infectious diseases or sepsis were examined using the semi-quantitative PCT-Q(®)-test (B.R.A.H.M.S., Germany) in 2010 and 2011. As controls, 75 cadavers were used for which there was no suspicion of a bacterial infectious disease or sepsis. Femoral blood was cultured from the cases and from controls, and samples from the brain, heart, lungs, liver, spleen and kidneys were examined histologically for findings seen in sepsis. Twelve cases in the sepsis/infectious disease group (48%) were classifiable as sepsis following synopsis of PCT levels, autopsy results, and histopathological and microbiological findings. This study shows that the semi-quantitative PCT-Q(®)-test is a useful supplementary marker in routine autopsy investigations, capable of classifying death as due to sepsis.

[The unrecognized myocardial infarction]

BACKGROUND AND OBJECTIVES

despite the improved quality of diagnostic technology, myocardial infarction still belongs to the diseases that are most frequently overlooked. Especially asymptomatic patients or patients with atypical symptoms are more common to be misdiagnosed. Failure to correctly diagnose is the leading cause of malpractice claims. It was the aim of this study to evaluate the records of patients who died from myocardial infarction and to analyse whether medical malpractice had occured in those who had undergone a medical examination shortly before their death.

METHODS

in the years 2008 and 2009 myocardial infarction had been diagnosed in 109 auotopsies performed at the Institute of Legal Medicine of the Hanover Medical School. The records of these patients who had died from myocardial infarction were retrospectively analysed with particular emphasis on an antemortem medical consultation, reported symptoms and diagnostic measures.

RESULTS

in 38 persons (34.9 %) an antemortem medical consultation or hospitalisation has taken place, whereby in five persons the diagnosis of myocardial infarction was suspected. In 33 persons, a myocardial infarction could not be diagnosed antemortem. In two cases an additionally cardiologic assessment was recommended to estimate if medical malpractice was present and in another two cases with insufficient diagnostic measures medical malpractice was reproached from forensic pathologists.

CONCLUSION

autopsy give the most accurate diagnostic information. On the other hand, it may provide an effective defence against medical malpractice litigation.

[Injury prevention as the physician's challenge]

In Germany, more than 9 million individuals yearly sustain injuries and more than 30,000 fatal injuries. Based on estimations, preventive measures could avoid more than one half of all accidents and could influence the other half of the accidents such that the injuries caused are minor. The aim of an initiative of the Study Group on Injury Prevention of the German Trauma Society (DGU) is a complete inventory of all prevention programs from different expert groups in Germany. A synopsis of the gathered knowledge should serve as a basis for further interdisciplinary preventive measures. The consistent interdisciplinary orientation of this program is a special characteristic including trauma surgery, orthopedics, pediatric surgery, pediatrics, sociology, legal medicine, psychology, sports medicine, geriatrics, anesthesiology, and others. Special attention was also directed to the age groups of children/adolescents and the elderly.

Intracartilaginous haemorrhagic lesions in strangulation?

This case control study was designed to investigate if laryngeal haemorrhages occur in cases of strangulation and whether these lesions are specific to strangulation. In the study 30 larynges from victims of fatal strangulation were examined (7 cases of manual strangulation, 12 cases of ligature strangulation, 11 cases of combined manual and ligature strangulation). The control group comprised 40 cases of death without any neck injuries and another group consisted of 5 cases of death caused by trauma with findings of non-strangulation neck injuries. In all the groups, only four solitary haemorrhages (two cases, one control, one non-strangulation neck injury) were observed that did not occur in the proximity of areas of blood accumulation. The results of our investigation suggest that histological evidence of blood accumulation or of haemorrhages in thyroid cartilage is not a reliable criterion to distinguish between haemorrhagic lesions due to strangulation and other types of blood accumulation or artefacts.

The time-dependent expression of fibronectin, MRP8, MRP14 and defensin in surgically treated human skin wounds

Fibronectin, MRP8, MRP14 and defensin were detected immunohistochemically in 46 surgically treated, fresh (hours old) human wounds and in wounds of 13 individuals who died immediately from fatal trauma (airplane crashes or train rollovers). In immediate fatal trauma, it was not possible to detect fibronectin outside of bleeding areas nor could inflammatory cells be visualized in the interstitium using MRP8, MRP14, or defensin antibodies. Fibronectin staining could be regularly demonstrated in wounds at least 20 min-old. Granulocytic infiltrates limited to the perivasal space could be detected 20-30 min after infliction of the wound expressing MRP8, MRP14 and defensin. It was also possible to detect fibronectin networks and MRP8-, MRP14-, and defensin-positive granulocytes and macrophages in particular wounds up to 30 days-old. No differences between the expression of MRP8 and MRP14 could be demonstrated in the wounds, the majority of which were only several hours old. As wound age increased, the number of defensin-positive granulocytes detected decreased. The immunohistochemical detection of fibronectin is a useful way to demonstrate vitality in fresh wounds, beginning about 20-30 min post-trauma. However, detection of MRP8, MRP14 and defensin provides no advantage over the routine histological detection of granulocytes and macrophages in wounds under 1-2 days old.

Lethal child neglect

The jurisdiction of the Hannover Institute of Legal Medicine recently experienced an unusually high incidence of lethal child neglect, with three cases in a 5-month period in 1999. Case 1: A girl received an inappropriate and inadequate diet of tea and oatmeal. The child was never breastfed, nor did it ever receive any other formula. The parents report the infant to have been healthy until she suddenly began projectile vomiting at the age of 13 weeks. For the next 3 days the infant was not able to maintain an adequate intake. The mother reports finding the child dead in its bed on the morning of the fourth day. Attempts by medical personnel to revive the child were unsuccessful. Case 2: A mother began spoon-feeding the infant puree on the fourth day of life, which according to the manufacturer's specifications is suitable for children between 4 and 8 months of age. At the age of 5 weeks, the infant was reported to have vomited half the just previously ingested meal, after which she took a nap. Some time later the parents observed the infant to be quite pale, however, assumed this was a result of sleep. When the mother finally did pick her up, the child was lifeless, and the parents brought her to the hospital. Medical personnel could however, only declare the infant dead, documenting a rectal temperature of 30 degrees C. Case 3: A 3.5-year-old girl died after her mother left the locked apartment and did not return for several weeks. The body of the child was found lying dressed on the floor in a state of advanced decay and mummification. Common findings in all three cases include lack of prenatal care, home birth without the help of a midwife, low socioeconomic status or maternal alcohol abuse, body weights below the 3rd percentile, extreme dehydration, fatty hepatic degeneration, thymic atrophy and signs of aspiration.

[Factitious wounds in plastic surgery]

Self-inflicted disorders of wound healing were diagnosed in two women (aged 24 and 25 years) after long years of history. A detailed medical history and the characteristic course helped to confirm the diagnosis. The artificial wounds were an expression of a severe psychic disturbance in both young women. Operative therapy was able to restore the local findings, the basic psychological disorder required a long-term psychotherapeutic treatment to prevent irreversible, partially iatrogenic co-induced somatic mutilations, due to an exceptionally high recurrence rate.

Immunohistochemical investigations on the course of astroglial GFAP expression following human brain injury

The course of GFAP expression by astrocytes has been immunohistochemically investigated during the first 30 weeks after human brain injury. In order to provide reliable data for a forensic wound age estimation, a quantitative morphometric analysis was performed considering the different topographic regions of the cortex as well as of the white matter. Compared to the GFAP immunoreactivity in unaltered control tissue, significantly increased numbers of GFAP positive astroglial cells could be detected adjacent to the cortical contusion from 1 day up to 4 weeks after brain injury.

The effect of lethal electrical shock on postmortem serum myoglobin concentrations

Postmortem serum myoglobin concentrations in blood from the femoral vein (peripheral withdrawal) and the heart (central withdrawal) of nine electrical fatalities were compared with those of 74 individuals who had died of other causes. Independent of the cause of death or topographical site, serum myoglobin concentrations rose dramatically with the passage of postmortem time (maximum concentrations in the control group: 975,100 micrograms/l). In 59% of the total sample (electrical fatalities plus controls), serum myoglobin concentrations were higher in the central blood, in the other 41% the concentrations were higher in the peripheral blood. The differences in concentrations between the peripheral and the central withdrawal area correlated with neither the postmortem interval nor the cause of death. Up to the second day postmortem there was a statistically significant difference in serum myoglobin concentrations between electrical fatalities and controls. The individual values within each group, however, varied widely and overlapped between groups. Controls who had also suffered muscle injury (polytrauma, myocardial infarction) did not have significantly higher serum myoglobin concentrations than controls without muscle injury. Myoglobin concentrations appear to be greatly influenced by the extent and duration of the muscle cramps induced by the electrical current. Correct interpretation of serum myoglobin concentrations depends on the knowledge of events surrounding the lethal electrical shock. Postmortem determination of serum myoglobin concentrations alone is, therefore, not sufficient to establish intravital exposure to electrical current and can aid the diagnosis only in special cases.

[Death caused by neglect?]

Over a period of several months a 23-year-old bedridden woman suffered from increasing cachexia with numerous decubital ulcera in the parental house. The parents induced the hospitalization not before the patient reached the agonal phase. The reported case was especially spectacular because the left arm had fallen off and lay beside the woman showing maggot infestation, mummification and skeletonization. Against the parents a preliminary investigation for manslaughter by negligence was instituted. This case report describes the unusual course of disease and the striking familiar situation.

Body and head position, covering of the head by bedding and risk of sudden infant death (SID)

We examined the position of the body and head, and the covering of the head by bedding on discovery in cases of sudden infant death (SID) in Lower Saxony. Between 1.1.1986 and 31.12.1992 structured, questionnaire-based interviews were carried out with parents of 140 SID victims. Control data were taken from a population-based cross-sectional study on infant sleeping position performed by the German Health Office (BGA) in autumn 1991. Of the SID cases 86.4% were discovered in the prone position [odds ratio (OR) = 7.4, 95% confidence interval (CI) = 4.3, 12.7] and 41.4% were found with the head covered. These infants were significantly older than those where the head was uncovered (p < 0.001) and covering of the head showed a significant association with a risk of SID (OR = 20.8; 95% CI = 11.5-37.6). Of the SID cases 27.9% were discovered in the face-down position. These infants were significantly younger than the infants who were discovered with the head in a side or supine position (p < 0.001). This study confirms the increased risk of SID associated with the prone position and suggests that this association could be related to the development of hypoxaemia or hypercapnia. Together with other factors such as heat stress or an infection, hypoxaemia or hypercapnia could culminate in SID if the arousal from sleep and auto-resuscitation apparently fails.

[Fatalities caused by exposure to heat]

Between 1978 and 1987 52 cases of death by burning or in connection with fire (13 females and 39 males) were examined at the Institute of Legal Medicine of the Medical School of Hannover. The causes were fires in flats (25), cars (15) and buildings(4), clothes set on fire (3) and explosions (3). In two cases death was caused by scalding. These cases could be divided into accidents (30), over 1/3 caused by smoking (11)), suicides (9) and homicides (6). The other seven cases could not be clarified definitively. Evidence of CO-elevation (38), soot inhalation (33), petechiae (11) and "crow's feet" (6) were noted. However, isolated findings cannot lead to a satisfactory assessment after death by burning. The reconstruction of events requires a comprehensive evaluation of the case history, the scene of death and the autopsy as well as complementary analyses. Therefore intensive cooperation between criminal investigators and forensic physicians is absolutely necessary.

Influence of postmortem changes on immunohistochemical reactions in skin

The influence of postmortem damage of tissues on the immunohistochemical diagnosis of wound age has not as yet been clarified. We utilized antibodies against the proteinase inhibitors alpha-1-antichymotrypsin and alpha-2-macroglobulin, fibronectin and lysozyme to study samples of skin which had been intact intravitally, but were damaged postmortem either by autolysis or compression with a surgical clamp at the time of dissection. Even in the absence of autolysis, antibodies against the proteinase inhibitors and fibronectin exhibited staining of tissue margins. Autolysis caused an increase in false positive results. In contrast, antibodies against lysozyme did not give false positive staining. There were no antigens sensitive to postmortem clamping and false positive results were not observed. Antibodies against proteinase inhibitors are not useful for the diagnosis of wound age because of a high number of false positive reactions in marginal areas. Fibronectin also showed false positive band-shaped staining patterns at the tissue margin. In addition, autolytic processes increase the number of false positives. The antibody against lysozyme is much less sensitive to autolysis and no false positive reactions were observed in our series of tests.

[Methods of suicide in an autopsy sample of the Institute of Forensic Medicine of the Hannover Medical School]

Between 1978 and 1987 513 cases of suicide were examined at the Institute of Legal Medicine of the Medical School of Hannover (337 males (65.7%) and 176 females (34.3%). The greatest share of the suicides was found in the age group 18 to 30. 42.1% of the cases showed positive alcohol concentrations with men accounting for a relatively higher share. The most frequently used methods for committing suicide were intoxications (28.1%), hanging (25.3%), firearms (17.2%), falling from great height (9.7%) and drowning (7.6%). The incidence in terms of sex showed marked differences in distribution, however. Women mostly used the following methods for committing suicide: Intoxication (37.4%), falling (17.6%) and hanging (17%). With men we found the following order: Hanging (29.7%), firearms (24.3%) and intoxications (23.1%). Compared with other institutes of legal medicine the five most frequent suicide methods showed similar distributions, but with a higher rate of intoxications. On the other hand there were distinct differences as to the relative frequency of the individual suicide methods in the total population and the respective number of autopsies performed. Especially in cases of gunshot wounds the number of autopsies performed to rule out homicide was higher. Of 2390 case of suicide registered in Greater Hannover an autopsy was ordered by the court in only 6.7%. According to our experience the autopsy rate seems too low, because homicide in the form of pretended suicide is not too rare.

Traumatic ponto-medullary tear: a case report

The aim of this report is to demonstrate the correlation between an extremely short time acting but strong force leading to incomplete rupture of the ponto-medullary junction (PMJ) accompanied by rupture of the basilar artery. Potential mechanisms involved in a combined hyperextension and axial torsion of the head followed by characteristic lesions at the PMJ are discussed. A 33-year-old male suffered a blunt head injury following a blow to the head, i.e. a head-butt. Resuscitation was performed for 45 min without success. At post mortem, there was a superficial periorbital haematoma on the right and a deep soft tissue bruise in the right fronto-parieto-temporal area, but no evidence of skull or dens axis fracture. A deep tear at the ponto-medullary junction was identified with rupture of the basilar artery, whereas at the tip of the tear, i.e. the floor of the IVth ventricle, only a thin tissue layer of about 2 mm remained intact. In contrast to the severity of these lesions, only mild subarachnoid hemorrhage was observed, but the ventricular system was filled with blood clot resulting from the retrograde flow of subarachnoid hemorrhage.

[Victims of homicide crimes--social conditions and circumstances of the crime]

152 autopsies were performed in cases of homicide at the Institute for Legal Medicine of the Hannover Medical School and the documents concerning the social situation of the victims, the relationship between offenders and victims and the circumstances involved in the crime were analyzed. Among the victims who were employed, workers and craftsmen followed by the group working in the service industry and trade were most commonly involved. Foreigners were victimized in 8% of the cases. In 129 cases (88.4%) there was a single and in 11.6% multiple offenders. 78.3% of the victims were murdered by a person they knew. Among relatives (38.7%), parents were most frequently implicated (56.5%). Arguments were the most common reason followed by quarrels within relationships, robbery and sexual offences. In most cases, the location of the crime was the home of the victim or of the victim and offender. In 92.8% of the cases, the corpse was found at the location of the crime.

Immunohistochemical examination of skin wounds with antibodies against alpha-1-antichymotrypsin, alpha-2-macroglobulin and lysozyme

The distribution of the proteinase inhibitors alpha-1-antichymotrypsin (alpha 1-act), alpha-2-macroglobulin (alpha-2-m) and lysozyme was analysed immunohistochemically in 27 intravitally acquired wounds, 3 postmortem skin lacerations and 9 specimens of undamaged skin. Intravitally acquired wounds demonstrated distinct positive reactions for all antibodies examined (alpha-1-act 66.6%; alpha-2-m 51.9%; lysozyme 25.9%). However the undamaged skin margins opposite the wound margins also gave positive reactions (alpha-1-act 51.8%; alpha-2-m 37.0%; lysozyme 25.9%). Nearly half of the control cases (specimens of undamaged skin) exhibited weak positive reactions for all 3 antibodies. These could be easily distinguished from the strong positive reactions observed in intravitally acquired wounds. False positive reactions were observed due to contamination resulting from contact with serum components, in cases of advanced autolysis of specimens, and as a result of fixation and drying artefacts. Even though immunohistochemical studies of alpha-1-act, alpha-2-m and lysozyme give some indications concerning wound vitality, they cannot be considered as proof because irrefutable differentiation of true positive and false positive reactions is not possible in all cases.