A novel liquid crystal (LC) based hollow waveguide phase shifter with an LC section of 14.6 mm is presented , operating at 80–110 GHz. As a proof-of-concept, the phase shifter is biased by using ...permanent magnets, which results in a differential phase shift of 307°–318° and an insertion loss of 2.1–2.7 dB in the desired frequency range of 99–105 GHz. Hence, a phase shifter figure of merit of 118°–148°/dB is determined, which are to the authors’ knowledge the highest values in this frequency range for passive phase shifters.
A
bstract
Based on 4.5 fb
−
1
data taken at seven center-of-mass energies ranging from 4.600 to 4.699 GeV with the BESIII detector at the BEPCII collider, we measure the branching fractions of
Λ
c
+
...→
Σ
+
+
hadrons
relative to
Λ
c
+
→
Σ
+
π
+
π
−
. Combining with the world average branching fraction of
Λ
c
+
→
Σ
+
π
+
π
−
, their branching fractions are measured to be (0
.
377
±
0
.
042
±
0
.
020
±
0
.
021)% for
Λ
c
+
→
Σ
+
K
+
K
−
, (0
.
200
±
0
.
023
±
0
.
011
±
0
.
011)% for
Λ
c
+
→
Σ
+
K
+
π
−
, (0
.
414
±
0
.
080
±
0
.
030
±
0
.
023)% for
Λ
c
+
→
Σ
+
ϕ
and (0
.
197
±
0
.
036
±
0
.
009
±
0
.
011)% for
Λ
c
+
→ Σ
+
K
+
K
−
(non-
ϕ
). In all the above results, the first uncertainties are statistical, the second are systematic and the third are from external input of the branching fraction of
Λ
c
+
→
Σ
+
π
+
π
−
. Since no signal for
Λ
c
+
→
Σ
+
K
+
π
−
π
0
is observed, the upper limit of its branching fraction is determined to be 0.13% at the 90% confidence level.
A
bstract
Using 15
.
6 fb
−
1
of
e
+
e
−
collision data collected at twenty-four center-of-mass energies from 4
.
0 to 4
.
6 GeV with the BESIII detector, the helicity amplitudes of the process
e
+
e
...−
→
π
+
π
−
ω
are analyzed for the first time. Born cross section measurements of two-body intermediate resonance states with statistical significance greater than 5
σ
are presented, such as
f
0
(500),
f
0
(980),
f
2
(1270),
f
0
(1370),
b
1
(1235)
±
, and
ρ
(1450)
±
. In addition, evidence of a resonance state in
e
+
e
−
→
π
+
π
−
ω
production is found. The mass of this state obtained by line shape fitting is about 4
.
2 GeV/
c
2
, which is consistent with the production of
ψ
(4160) or
Y
(4220).
Helicity amplitude analysis of χcJ→ ϕϕ Balossino, I.; Bettoni, D.; Chen, G. ...
The journal of high energy physics,
05/2023, Letnik:
2023, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
Using (447.9
±
2.3) million
ψ
(3686) events collected with the BESIII detector, the decays of
χ
cJ
→ ϕϕ
(
J
= 0
,
1
,
2) have been studied via the decay
ψ
(3686)
→ γχ
cJ
. The branching ...fractions of the decays
χ
cJ
→ ϕϕ
(
J
= 0
,
1
,
2) are determined to be (8
.
59 ± 0
.
27 ± 0
.
20) × 10
−
4
, (4
.
26 ± 0
.
13 ± 0
.
15) × 10
−
4
, and (12
.
67 ± 0
.
28 ± 0
.
33) × 10
−
4
, respectively, which are the most precise measurements to date. From a helicity amplitude analysis of the process
ψ
(3686)
→ γχ
cJ
, χ
cJ
→ ϕϕ, ϕ → K
+
K
−
, the polarization parameters of the
χ
cJ
→ ϕϕ
decays are determined for the first time.
A
bstract
Using (448
.
1
±
2
.
9)
×
10
6
ψ
(3686) events collected with the BESIII detector at the BEPCII collider, the decay
ψ
(3686)
→
Σ
−
Σ
¯
+
is observed for the first time with a branching ...fraction of (2
.
82
±
0
.
04
stat
.
±
0
.
08
syst
.
)
×
10
−
4
, and the angular parameter
α
Σ
−
is measured to be 0
.
96
±
0
.
09
stat
.
±
0
.
03
syst
.
.
A
bstract
Using data samples with an integrated luminosity of 19 fb
−
1
at twenty-eight center-of-mass energies from 3.872 GeV to 4.700 GeV collected with the BESIII detector at the BEPCII ...electron-positron collider, the process
e
+
e
−
→
ηπ
+
π
−
and the intermediate process
e
+
e
−
→
ηρ
0
are studied for the first time. The Born cross sections are measured. No significant resonance structure is observed in the cross section lineshape.
New precise unpolarised differential cross sections of deuteron–proton elastic scattering have been measured at 16 different deuteron beam momenta between pd=3120.17MeV/c and pd=3204.16MeV/c at the ...COoler SYnchrotron COSY of the Forschungszentrum Jülich. The data, which were taken using the magnetic spectrometer ANKE, cover the equivalent range in proton kinetic energies from Tp=882.2MeV to Tp=918.3MeV. The experimental results are analysed theoretically using the Glauber diffraction model with accurate nucleon–nucleon input. The theoretical cross section at Tp=900MeV agrees very well with the experimental one at low momentum transfers t. There are, however, significant deviations for |t|>0.2(GeV/c)2 that must be investigated further.
Living conditions in eastern Germany have changed rapidly since unification in 1990 and little is known about how these changes affect the prevalence of atopic diseases. This study describes methods ...and prevalences of a large epidemiological project investigating determinants of childhood asthma and allergies in eastern (Dresden and Leipzig) and western (Munich) Germany in 1995/1996. Community based random samples of 9-11 yr old children in Dresden (n=3,017) and Munich (n=2,612), and of 5-7 yr old children in Dresden (n=3,300), Leipzig (n=3,167) and Munich (n=2,165) were studied by parental questionnaires, bronchial challenges with hypertonic saline, skin examination, skin-prick tests, and measurements of specific and total serum immunoglobulin (Ig)E using Phase II modules of the International Study of Asthma and Allergies in Childhood (ISAAC). In 9-11 yr old children, the prevalence of physician diagnosed asthma (7.9% versus 10.3%; p<0.01) and bronchial hyperresponsiveness (15.7% versus 19.9%; p<0.05) was lower in Dresden than in Munich. No difference between Munich and Dresden was observed in the prevalence of diagnosed hay fever, skin test reactivity to > or = 1 allergen, and increased levels (>0.35 kU x L(-1)) of specific IgE against inhalant and food allergens. Symptoms and visible signs of atopic eczema tended to be more prevalent in Dresden. Similar East-West differences between the three study areas were seen in the younger age group. These findings are in line with recently observed increases in the prevalence of hay fever and atopic sensitization, but not of asthma and bronchial hyperresponsiveness, among 9-11 yr old children in Leipzig.
The German reunification offers a unique opportunity to study the impact of environmental factors on the development of childhood respiratory and allergic disorders in ethnically similar populations. ...We investigated the prevalence of asthma, hay fever, atopy, and bronchial hyperresponsiveness (BHR) in 9- to 11-year old children in West Germany (n = 5,030) and East Germany (n = 2,623). A self-administered questionnaire was distributed to the parents. Children underwent cold air challenge and allergy skin prick tests. Atopic sensitization was considerably more frequent in West German children than in their peers in East Germany (36.7% versus 18.2%; odds ratio OR = 2.6, p < 0.0001). The prevalence of current asthma and hay fever was significantly higher in West Germany when compared with that in East Germany (5.9% versus 3.9%; OR = 1.5, p < 0.0001 and 8.6% versus 2.7%; OR = 3.4, p < 0.0001, respectively). Bronchitis, however, was more prevalent in East Germany than in the western part of the country. The prevalence of BHR as assessed by cold air challenge was higher in West Germany compared with that in East Germany (8.3% versus 5.5%, OR = 1.6, p < 0.001). Logistic regression showed that the West German study area was no longer a significant independent determinant of asthma once sensitization to mites, cats, and pollen was taken into account. We conclude that sensitization to aeroallergens is strikingly more frequent in West Germany than in East Germany and this may explain the differences in the prevalence of asthma and hay fever between the two parts of the country.
OBJECTIVES--To compare the prevalence of asthma and allergic disorders among children in Munich, western Germany, and Leipzig, eastern Germany, where environmental exposure, particularly air ...concentrations of sulphur dioxide and particulate matter, and living conditions have differed over the past 45 years. DESIGN--Prevalence surveys among school-children aged 9-11 years in Leipzig and Munich. Self completion of written questionnaire by the children's parents and lung function measurements. SUBJECTS--1051 children in Leipzig and 5030 in Munich. SETTING--Primary schools. MAIN OUTCOME MEASURES--Reported lifetime prevalence of asthma and allergic disorders, and bronchial hyperresponsiveness assessed by cold air inhalation challenge. RESULTS--The lifetime prevalence of asthma diagnosed by a doctor was 7.3% (72) in Leipzig and 9.3% (435) in Munich; prevalence of wheezing were 20% (191) and 17% (786) respectively. The prevalence of diagnosed bronchitis was higher in Leipzig than Munich (30.9% (303) v 15.9% (739); p < 0.01). A significant drop in forced expiratory volume (> 9%) after cold air challenge was measured in 6.4% (57) of children in Leipzig and in 7.7% (345) of those in Munich. Hay fever (2.4% (24) v 8.6% (410); p < 0.01) and typical symptoms of rhinitis (16.6% (171) v 19.7% (961); p < 0.05) were reported less often in Leipzig than in Munich. CONCLUSIONS--No significant differences were seen in the lifetime prevalence of asthma, wheezing, and bronchial hyperresponsiveness between children in Leipzig and Munich. The lifetime prevalence of bronchitis was higher in Leipzig than in Munich. The lower prevalence rates of allergic disorders in Leipzig could point toward aetiological factors that are associated with Western lifestyle and living conditions.
PDF
