Evidence for direct CP violation in the measurement of the Cabbibo-Kobayashi-Maskawa angle γ with B∓ → D(*)K(*)∓ decays

We report the measurement of the Cabibbo-Kobayashi-Maskawa CP-violating angle γ through a Dalitz plot analysis of neutral D-meson decays to K(S)(0) π+ π- and K(S)(0) K+ K- produced in the processes B∓ → DK∓, B∓ D* K∓ with D* → Dπ(0), Dγ, and B∓ → DK*∓ with K*∓ → K(S)(0) π∓, using 468 million BB pairs collected by the BABAR detector at the PEP-II asymmetric-energy e+ e- collider at SLAC. We measure γ = (68 ± 14 ± 4 ± 3)° (modulo 180°), where the first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the uncertainty in the description of the neutral D decay amplitudes. This result is inconsistent with γ = 0 (no direct CP violation) with a significance of 3.5 standard deviations.

Measurement of D0-D0 mixing parameters using D0 → K(S)(0)π+ π- and D0 → K(S)(0)K+ K- decays

We report a direct measurement of D0-D0 mixing parameters through a time-dependent amplitude analysis of the Dalitz plots of D(0) → K(S)(0) π+ π- and, for the first time, D0 → K(S)(0)K+ K- decays. The low-momentum pion π(s)(+) in the decay D*+ → D0 π(s)(+) identifies the flavor of the neutral D meson at its production. Using 468.5 fb(-1) of e+ e- colliding-beam data recorded near square root(s)=10.6 GeV by the BABAR detector at the PEP-II asymmetric-energy collider at SLAC, we measure the mixing parameters x = [1.6 ± 2.3(stat) ± 1.2(syst) ± 0.8(model)] × 10(-3), and y = [5.7 ± 2.0(stat) ± 1.3(syst) ± 0.7(model)] × 10(-3). These results provide the best measurement to date of x and y. The knowledge of the value of x, in particular, is crucial for understanding the origin of mixing.

Observation of symmetrical reflection sidebands in a silica suspended-core fiber Bragg grating

We have observed symmetrical sidebands in reflection from Bragg grating written in a silica suspended-core fiber, which are caused by longitudinal periodic refractive index modulation in the Ge-doped suspended-core fiber with a core diameter of approximately 1.3 microm. Our simulation shows that the effective refractive index of the guided mode varied by 0.023% along the fiber with a period of approximately 650 microm. The periodic index variation can lead to amplitude modulation of fiber Bragg gratings, which can be studied by observing the spectra of a fiber Bragg grating written in the Ge-doped core. In addition, we have also characterized the temperature and strain responses of the fiber Bragg gratings, and showed that both responses in the suspended-core fiber are 20 to 25% lower than that of a fiber Bragg grating written on a conventional fiber.

Measurements of charged current lepton universality and |Vus| using tau lepton decays to e- ν(e) ν(τ), μ- ν(μ) ν(τ), π- ν(τ), and K- ν(τ)

Using 467  fb(-1) of e+e- annihilation data collected with the BABAR detector, we measure (B(τ- → μ- ν(μ) ν(τ)))/(B(τ- → e- ν(e) ν(τ))) =(0.9796±0.0016±0.0036), (B(τ- → π- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.5945±0.0014±0.0061), and (B(τ- → K- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.03882±0.00032±0.00057), where the uncertainties are statistical and systematic, respectively. From these precision τ measurements, we test the standard model assumption of μ-e and τ-μ charge current lepton universality and provide determinations of |Vus| experimentally independent of the decay of a kaon.

MR carotid plaque imaging and contrast-enhanced MR angiography identifies lesions associated with recent ipsilateral thromboembolic symptoms: an in vivo study at 3T

BACKGROUND AND PURPOSE

Recent research has suggested the importance of plaque composition to identify patients at risk for stroke. This study aims to identify specific plaque features on 3T carotid MR imaging and CE-MRA associated with recent carotid thromboembolic symptoms in patients with mild/moderate versus severe stenosis.

MATERIALS AND METHODS

Ninety-seven consecutive patients (symptomatic, 13; asymptomatic, 84) with 50%-99% stenosis by sonography or CT angiography underwent carotid plaque imaging combined with MRA at 3T. The symptomatic carotid artery or the most stenotic asymptomatic carotid artery was chosen as the index vessel to be analyzed. Plaque features were compared by symptomatic status in patients with mild/moderate (30%-70%) versus severe (70%-99%) stenosis on MRA.

RESULTS

Ninety (92.8%) patients had sufficient image quality for interpretation. In 50 patients with mild/moderate stenosis, there were significant associations between the presence of the following plaque characteristics and symptoms: thin/ruptured fibrous cap (100% versus 36%, P = .006) and lipid-rich necrotic core (100% versus 39%, P = .022), with marginal association with hemorrhage (86% versus 33%, P = .055). In 40 patients with severe stenosis, only the angiographic presence of ulceration (86% versus 36%, P = .039) was associated with symptoms.

CONCLUSIONS

Several plaque components identified on 3T MR imaging are correlated with recent ipsilateral carotid thromboembolic symptoms. These preliminary results also suggest that associations between plaque characteristics and symptom history may vary by degree of stenosis. If confirmed in larger studies, carotid MR imaging may distinguish stable from unstable lesions, particularly in individuals with mild/moderate stenosis in whom the role of surgical intervention is currently unclear.

POLIOMYELITIS IN THE CYNOMOLGUS MONKEY : II. RESISTANCE TO SPREAD OF INFECTION IN THE CENTRAL NERVOUS SYSTEM FOLLOWING EXPOSURES OF THE MUCOUS MEMBRANES TO VIRUS, WITH COMMENTS ON NON-PARALYTIC POLIOMYELITIS

1. Repeated non-traumatic exposures to poliomyelitis virus of the mucous membranes of the upper respiratory tract and of various portions of the alimentary tract in 5 cynomolgus monkeys, extending over a period of 9 to 14 months, were followed by a definite, though limited resistance to intracerebral inoculation to the homologous strain of virus in 4 of them. Only one monkey developed paralysis (20 per cent incidence) and the other 4 remained free of signs and symptoms of the disease. 92 per cent of 25 previously untreated monkeys developed paralysis with the same strain after intracerebral inoculation. 2. Microscopic examination of the central and peripheral nervous systems of the 4 non-paralytic cases revealed in all instances typical lesions in the central nervous system descending from the level of inoculation into the brain-stem but in only 2 into the spinal cord and then only in limited, small areas. Lesions were found in the peripheral ganglia in all animals which corresponded in distribution with the surface membranes previously exposed to virus. No lesions were found in the central nervous system indicative of invasion preceding the intracerebral inoculation. 3. Our observations point to the acquisition by the immune animal, as a result of surface exposure, of the power to limit the spread of infection in the central nervous system rather than of the capacity entirely to prevent implantation and multiplication of virus. 4. This limitation of spread, it is suggested, resembles the tendency so commonly seen in human poliomyelitis of the disease to "halt" at some stage of its evolution, resulting in the various clinical gradations in extent and severity of involvement (subclinical, abortive, non-paralytic, mild paralytic forms, etc.) 5. The experimental methods of exposure, previous to intracerebral inoculation, employed in our study are compared with the natural exposures of human beings during the course of life, which, as age advances, lead to increasing resistance to poliomyelitis and to an increasing incidence of specific neutralizing antibodies in the blood. 6. The mechanism of resistance is obscure. It may be related to the continuing presence of infection in the peripheral ganglia but this is as yet unproved.

POLIOMYELITIS IN THE CYNOMOLGUS MONKEY : I. COMPARISON OF THE UPPER PORTION OF THE ALIMENTARY TRACT WITH ITS LOWER, GASTROINTESTINAL PORTION AS A PORTAL OF ENTRY, WITH SPECIAL REFERENCE TO THE PERIPHERAL GANGLIA

1. Cynomolgus monkeys were subjected to a series of non-traumatic exposures of the mucous membranes of the alimentary tract, designed to test the relative permeability to poliomyelitis virus of its upper and lower portions. 2. In the first stage, dried poliomyelitis virus of tested potency was administered in fat-covered capsules to 26 monkeys in such a way as to avoid contamination of the oropharynx but to permit thorough exposure of the gastro-intestinal mucosae. No clinical evidence of poliomyelitic infection appeared. 3. Subsequent application of small amounts of virus to the tongues of 18 of the same monkeys caused paralytic poliomyelitis in one of them. 4. Virus given subsequently by enema to 11 of the monkeys caused no clinical manifestations of poliomyelitis. 5. Of 7 monkeys later treated with virus by oronasal spraying, one developed typical preparalytic signs of infection, and the distribution of lesions indicated that entry had occurred through the afferent nerves of the oropharynx and, possibly, the esophagus. 6. The 6 surviving monkeys were exposed to virus by inhalation. One of them developed paralytic poliomyelitis by olfactory entry. The others appeared to have acquired some resistance to infection. 7. The 5 surviving monkeys were inoculated intracerebrally, as a test of immunity. One of them developed paralytic poliomyelitis. The other 4 showed no clinical signs of infection, but all had typical lesions of varying extent and intensity in the central nervous system. 8. A histological examination of the peripheral nervous ganglia in 12 of the exposed monkeys sacrificed at various stages of the experiments revealed lesions compatible with poliomyelitis in all. Ganglia connected with the head alone (Gasserian, cervical sympathetic) were more constantly and, on the average, more severely involved than the celiac, which is connected only with the intestine. 9. While the celiac ganglion was involved in 7 cases, no evidence was found of the spread of infection from it to the spinal cord.

STUDIES ON THE ENTRY AND EGRESS OF POLIOMYELITIC INFECTION : I. NEUTROTROPIC INFECTION OF THE PERIPHERAL GANGLIA IN APPARENTLY HEALTHY MONKEYS FOLLOWING CASUAL EXPOSURE

In rhesus and cynomolgus monkeys without signs or symptoms of poliomyelitis, a comparison of the incidence, numbers, size, and character of lesions in certain peripheral ganglia (gasserian, nodose, superior cervical sympathetic, and celiac) was made between 9 "new" animals sacrificed 1 to 3 days after arrival in a laboratory devoted exclusively to poliomyelitis research, and 17 "old" animals housed there without special isolation precautions for periods ranging from 17 days to 10½ months. The comparison showed that the "old" animals had more infiltrative lesions of various sizes than the "new" and that neuronophagia occurred in 65 per cent of the "old" animals as compared with none in the "new." The heaviest and most frequent involvement occurred in the gasserian and superior cervical sympathetic ganglia, while that of the nodose (vagal afferent) ganglia was somewhat less, and that of the celiac ganglia was still less and without neurophagia. The ganglia of the VII and IX cranial nerves were also examined and showed no lesions of note. Reasons are presented for believing that the lesions were of centripetal and not of centrifugal origin. The lesions, while not positively identified as poliomyelitic, were of similar morphology, were presumably due to an infective neurotropic agent, and were acquired under conditions of potential exposure to poliomyelitis virus. The possibility is suggested that the asymptomatic acquisition of neurotropic lesions in this group of casually exposed monkeys can be comparable to the acquisition of "subclinical" poliomyelitis in man.

POLIOMYELITIS IN THE CYNOMOLGUS MONKEY : III. INFECTION BY INHALATION OF DROPLET NUCLEI AND THE NASOPHARYNGEAL PORTAL OF ENTRY, WITH A NOTE ON THIS MODE OF INFECTION IN RHESUS

1. Poliomyelitis virus suspensions were atomized so as to produce dry droplet nuclei which, suspended in air, were introduced into a special infecting chamber and inhaled by test animals, both rhesus and cynomolgus monkeys. 2. Without olfactory blockade, 5 of 7 rhesus and 6 of 7 cynomolgus monkeys developed poliomyelitis of the CNS with entry through the olfactory nerves. 3. With olfactory blockade, 2 of 35 rhesus and 4 of 10 cynomolgus monkeys developed this form of the disease by routes proved by serial sections of the olfactory bulbs not to have been olfactory. 4. The neural pathways of infection from the mucous surfaces to the CNS in the 4 cynomolgus monkeys with blockade were shown in 2 instances to have been the afferent fibers of the trigeminal nerve into the Gasserian ganglion and thence to its central connections in the pons-medulla; in another case this was the probable route. In one instance the pathway consisted of the sympathetic fibers of the nose or nasopharynx into the cervical sympathetic ganglia and thence into the uppermost levels of the thoracic cord. The routes in the 2 rhesus monkeys with non-olfactory takes were not accurately determined but in one there was suggestive evidence of entry through the trigeminal nerve. 5. Study of the peripheral ganglia in a number of exposed cynomolgus and rhesus monkeys, including several with no demonstrated involvement of the CNS, revealed lesions most constantly in the Gasserian ganglia; less so in the cervical sympathetics and still less so in the celiac. In 2 rhesus monkeys dying of other causes a few days after exposure, lesions were limited to the Gasserian ganglia. No evidence was found in any case of passage of infection from the celiac ganglia into the CNS. 6. The importance of the peripheral ganglia as intermediate stations in the centripetal passage of infection from the body surface is again emphasized. 7. Comparison of the present with a previous study suggests that infection by inhalation of virus occurs with greater ease than by ingestion.

Test of lepton universality in Υ(1S) decays at BABAR

The ratio R(τμ)(Υ(1S))=Γ(Υ(1S)→τ+ τ-)/Γ(Υ(1S)→μ+ μ-) is measured using a sample of (121.8±1.2)×10(6)Υ(3S) events recorded by the BABAR detector. This measurement is intended as a test of lepton universality and as a search for a possible light pseudoscalar Higgs boson. In the standard model (SM) this ratio is expected to be close to 1. Any significant deviations would violate lepton universality and could be introduced by the coupling to a light pseudoscalar Higgs boson. The analysis studies the decays Υ(3S)→Υ(1S)π+ π-, Υ(1S)→l+ l-, where l=μ, τ. The result, R(τμ)(Υ(1S))=1.005±0.013(stat)±0.022(syst), shows no deviation from the expected SM value, while improving the precision with respect to previous measurements.