Dark-Sector Search via Pion-Produced η and η

We present the first results from a proof-of-concept search for dark sectors via invisible decays of pseudoscalar η and η^{'} mesons in the NA64h experiment at the CERN SPS. Our novel technique uses the charge-exchange reaction of 50 GeV π^{-} on nuclei of an active target as the source of neutral mesons. The η,η^{'}→invisible events would exhibit themselves via a striking signature-the complete disappearance of the incoming beam energy in the detector. No evidence for such events has been found with 2.9×10^{9} pions on target accumulated during one day of data taking. This allows us to set a stringent limit on the branching ratio Br(η^{'}→invisible)<2.1×10^{-4} improving the current bound by a factor of ≃3. We also set a limit on Br(η→invisible)<1.1×10^{-4} comparable with the existing one. These results demonstrate the great potential of our approach and provide clear guidance on how to enhance and extend the sensitivity for dark sector physics from future searches for invisible neutral meson decays.

Search for Light Dark Matter with NA64 at CERN.

Thermal dark matter models with particle χ masses below the electroweak scale can provide an explanation for the observed relic dark matter density. This would imply the existence of a new feeble interaction between the dark and ordinary matter. We report on a new search for the sub-GeV χ production through the interaction mediated by a new vector boson, called the dark photon A^{'}, in collisions of 100 GeV electrons with the active target of the NA64 experiment at the CERN SPS. With 9.37×10^{11} electrons on target collected during 2016-2022 runs NA64 probes for the first time the well-motivated region of parameter space of benchmark thermal scalar and fermionic dark matter models. No evidence for dark matter production has been found. This allows us to set the most sensitive limits on the A^{'} couplings to photons for masses m_{A^{'}}≲0.35 GeV, and to exclude scalar and Majorana dark matter with the χ-A^{'} coupling α_{D}≤0.1 for masses 0.001≲m_{χ}≲0.1 GeV and 3m_{χ}≤m_{A^{'}}.

Search for a New B-L Z

A search for a new Z^{'} gauge boson associated with (un)broken B-L symmetry in the keV-GeV mass range is carried out for the first time using the missing-energy technique in the NA64 experiment at the CERN SPS. From the analysis of the data with 3.22×10^{11} electrons on target collected during 2016-2021 runs, no signal events were found. This allows us to derive new constraints on the Z^{'}-e coupling strength, which, for the mass range 0.3≲m_{Z^{'}}≲100 MeV, are more stringent compared to those obtained from the neutrino-electron scattering data.

Photoproduction of the f_{2}(1270) Meson Using the CLAS Detector.

The quark structure of the f_{2}(1270) meson has, for many years, been assumed to be a pure quark-antiquark (qq[over ¯]) resonance with quantum numbers J^{PC}=2^{++}. Recently, it was proposed that the f_{2}(1270) is a molecular state made from the attractive interaction of two ρ mesons. Such a state would be expected to decay strongly to final states with charged pions due to the dominant decay ρ→π^{+}π^{-}, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction γp→π^{0}π^{0}p, using the CEBAF Large Acceptance Spectrometer detector at Jefferson Lab for incident beam energies between 3.6 and 5.4 GeV. Differential cross sections, dσ/dt, for f_{2}(1270) photoproduction are extracted with good precision due to low backgrounds and are compared to theoretical calculations.

Novel Way to Search for Light Dark Matter in Lepton Beam-Dump Experiments.

A novel mechanism to produce and detect light dark matter in experiments making use of GeV electrons (and positrons) impinging on a thick target (beam dump) is proposed. The positron-rich environment produced by the electromagnetic shower allows us to produce an A^{'} via nonresonant (e^{+}+e^{-}→γ+A^{'}) and resonant (e^{+}+e^{-}→A^{'}) annihilation on atomic electrons. The latter mechanism, for some selected kinematics, results in a larger sensitivity with respect to limits derived by the commonly used A^{'}-strahlung. This idea, applied to beam-dump experiments and active beam-dump experiments, pushes down the current limits by an order of magnitude.

[Effectiveness and innocuousness of the association of calcium dobesilate, dexamethasone acetate and lidocaine versus prednisolone capronate with dibucaine clorohydrate in the treatment of hemorrhoids-]. / Effectividad e inocuidad de la asociacion de dobesilato de calcio con acetato de dexametasona y lidocaina con capronato de prednisolona con clorhidrato de dibucaina, en el tratamiento de las hemorroides.

The objective of the present study was to compare properties of two associations in the topical treatment of hemorrhoids. They were included 40 patient with diagnosis of internal hemorrhoids grade 1 or 2, which was indicated topic treatment after the realization of an interrogatory and anoscopy. The treatment received according to a randomized and double blind design: A = dobesilate of calcium with acetato of dexamethasone and lidocaine or B = Capronato of Prednisolone with Clorhidrato of dibucaina, applied twice a day. They were carried out controls every 7 days. In each control was carried out interrogatory and respective anoscopy. There was a prevalence of the females, and the age corresponded to the 5t decade of the life. Patients of the treatment. A presented greater number of predisponents factors, but minor percentage of previous treatments. As for the evaluation of the punctuation of symptoms and of the grade of Hemorrhoids, comparing beginning and final, they didn't show significant difference interproduct confirming the effectiveness and similar inocuity. In both products was observed a important improvement concerning to the symptoms and grade of hemorrhoids but the patients of the treatment A precipitated the greater speed. As for the evaluation made by the phisicians, the treatment A (88%) and B (85.7%) the got successful outputs. The opinion of the patients was a 100% of marked goods or moderated beneficial. Both treatments were successful so much in effectiveness like in inocuity although the treatment A were always got the best efectiveness outputs.

[Primary immunoproliferative small intestinal disease]. / Enfermedad inmunoproliferativa primaria del intestino delgado (IPSID).

We report two cases of Primary small Intestinal Lymphoma (IPSID), in adults. The clinical presentation was, watery diarrhea and weight loss. The histology of this cases was non-Hodgkin's Lymphoma, and the treatment was chemotherapy.

[Use of glucomannan dietary fiber in changes in intestinal habit]. / Uso de la fibra dietética de glucomannan en la modificación del hábito intestinal.

It has been proven that fiber is effective in the treatment of multiple nosological entities, specially of the colonic pathology. In the present study, two dose of Glucomannan (3 gr/day and 4 gr/day) were evaluated within the modification of the intestinal habit and stool characteristics. 60 patients were included in a random, parallel, double blind, cross over trial study versus placebo. The modification of the intestinal habit was evaluated through variations of daily and weekly evacuations, appraising the stool's consistency and size, satiety after meals tiresomeness between meals, constipation, diarrhea and flatulence. An increase in the number of daily and weekly evacuations during the Glucomannan vs placebo treatment was appreciated and, between the two dose of Glucomannan, a difference was observed as to the large the dose, the large the number of daily and weekly evacuations. Evacuations during the phase of Glucomannan 3 gr/day increased 0.5 times per day, 3 more per week above baseline values. On the 4 gr/day treatment of Glucomannan evacuations increased 0.9 times per day, 6 more per week above baseline values. Patient during the placebo period presented no statistically significant different. No difference was appreciated as to post-meal satiety, nor tiresomeness between meals, possibly due to treatment periods being 5 weeks long. No larger number of cases with diarrhea or flatulence were appreciated with the use of Glucomannan. Glucomannan proved to be superior to placebo, and the 3 gr/day and 4 gr/day doses turned out to beneficial in the improvement of the assessed parameters--better results were obtained using 4 gr/day of Glucomannan than 3 gr/day.

[Hepatic tolerance of aceclofenac]. / Tolerancia hepática del aceclofenac.

NSAID's are largely used drugs. Among the reported side effects of this type of drugs is liver damage. 73 patients suffering from diverse rheumatological pathologies (arthrosis 46.6%, rotators 9.68%, rheumatoid arthritis 21.92%, lumbalgia 5.48%, other diagnosis 6.85%) were evaluated. Aceclofenac (AC) 100 mg. dose every 12 hours was administered. A Transaminase value determination was taken both at the beginning and end of medication for each patient. Average age of patients was 52.71 years, 78% being female. Treatment was administered as follows, 42.47% of the patients received a 60 days treatment, 28.8% a 45 days treatment, 23.3% a 30 days treatment and 5.47% received a 15 days treatment. Reported mean GOT value at the beginning was 16.6 U, at the end 17.01 U. GPT initial value was 15.84 U and final 16.53 U. A GOT increase, 20 U to 50 was observed in a single patient. GPT was also increased from 32 U to 47 U in one case. Results led us to a no liver damage report of the NSAID's AC in these group of patients.

[Retrograde endoscopic cholangiopancreatography. Incidence of bacteremia]. / Colangiopancreatografía retrógrada. Incidencia de bacteriemia.

ERCP like all the endoscopic procedures, implies some risks of complications, between them, infections. Bacteremia may occur in any endoscopic and gastrointestinal procedure. The rate on ERCP is about 0 to 5.6%. In the present investigation we intended to determine the rate of bacteremia produced by ERCP, the organism that cause bacteremia and to correlate ductal pathology, stasis and bacteremia. From May to October 1988, at the Hospital Vargas of Caracas, 22 ERCP were performed in patients that were included for analysis. Haemocultives were taken for aerobics and anaerobics, gems before ERCP, immediately after the cannulation of biliary and/or pancreatic ducts and 5 minutes later after concluding the study. A high incidence of bacteremia was reported, 13.6%, all the previous haemocultives were negative. The positive haemocultives were during the cannulation procedure and no haemocultive after the study was positive. The organism isolate were Peptococcus sacharoliticcus and Staphylococcus epidermidis both of the normal flora of small intestine and the last one on the skin too. There were not relation between the ductal pathology, stasis and bacteremia. Some organisms were related to nosocomial agents, we considered though the disinfection and polishment of the accessories and equipment adequate. It is recommendable to use prophylactic antibiotic in immunosuppressed patients with valvular prosthesis.

[Percutaneous liver biopsy in outpatients]. / Biopsia hepática percutánea en pacientes ambulatorios.

We studied prospectively 44 patients with diffuse liver disease. We performed percutaneous liver biopsy in these outpatients. They were required to be in absolute response during the following 4-6 hours after the biopsy was completed. After that period, they could go home and have a relative rest for the remnant day. These patients were followed by clinical evaluation and by real time abdominal ultrasound. We found some complications: Transitory arterial hypotension, pain in the site of puncture, hepatic hematomas. Only one of the patients with hematomas required hospitalization during 24 hours. The mortality was 0%. According to our experience, the hepatic biopsy is a procedure that can be performed in outpatients with a wide margin of security. An important point of view to consider is the economic advantage since it means a decrease in costs by each hepatic biopsy accomplished considering the cost/day of hospitalization.