We investigate the Y(4260) resonance recently discovered by the BaBar Collaboration. We propose the observation of its decay into J/ψππ and its non-observation into open charm as a consequence of it ...being a charmonium hybrid state with a magnetic constituent gluon. We prove a selection rule forbidding its decay into two S-wave charmed mesons in any potential model. We suggest a generalisation of the selection rule based only on the heavy quark nature of the charm.
We propose to measure the
τ
-
→
K
1
-
ν
τ
→
(
K
-
ω
)
ν
τ
→
(
K
-
π
+
π
-
π
0
)
ν
τ
decay in order to determine the
K
1
axial vector mixing angle
θ
K
1
. We derive, for the first time, the ...differential decay rate formula for this decay mode. Using the obtained result, we perform a sensitivity study for the Belle (II) experiment. We will show that the
K
-
π
+
π
-
π
0
spectrum of the
τ
-
→
K
1
-
ν
τ
→
(
K
-
ω
)
ν
τ
→
(
K
-
π
+
π
-
π
0
)
ν
τ
decay can discriminate the two solutions
θ
K
1
=
∼
30
∘
or
∼
60
∘
observed in the other measurements.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this paper, we discuss the theoretical framework and the experimental measurements of the magnetic moment of the charmed baryons. We first review the theoretical predictions of the
Λ
c
+
magnetic ...moment and show that the measurements of the magnetic moments of other charmed baryons, such as
Ξ
c
, allow to perform detailed spectroscopy studies. The magnetic moment of the charm quark can be determined using radiative charmonium decay, which can be compared to the
Λ
c
+
magnetic moment within theoretical models. The present results show a tension with majority of theoretical predictions. The magnetic moment of the charmed baryons could potentially be measured directly, using bent-crystal experiments at LHC. The possibility to measure precisely the magnetic moments of charmed baryons needs precise measurement of their polarisation and weak decay parameters. In this paper, we revisit the formalism of the angular analysis needed for these measurements and make a detailed evaluation of initial polarisation of deflected
Λ
c
baryons as a function of crystal orientation. We found a special orientation of the crystal that gives the opportunity to measure the
Λ
c
dimensionless electric dipole moment almost with the same precision as its
g
-factor, which is more than an order of magnitude more efficient than suggested before.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We propose a model independent extraction of the hadronic information needed to determine the photon polarization of the b→sγ process by the method utilizing the B→K1γ→Kππγ angular distribution. We ...show that exactly the same hadronic information can be obtained by using the B→J/ψK1→J/ψKππ channel, which leads to a much higher precision.
We propose a novel approach to measure the branching ratios of the leptonic η(′)→μ+μ− decays by using charmed meson decays, namely, D(s)+→π+η(′)(→μ+μ−) and D0→K−π+η(′)(→μ+μ−). We advocate that the ...data available at LHCb can already yield a new measurement of Br(η→μ+μ−) with accuracy competitive with the current world average. We also estimate that using the data collected by LHCb between 2015 and 2018 in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.0 fb−1, the relative uncertainties to this branching ratio can be reduced down to ∼10%. We also show that the first observation of Br(η′→μ+μ−) may be possible with the upgrade of the LHCb experiment.
Is Vtb≃1? Alwall, J.; Frederix, R.; Gérard, J.-M. ...
The European physical journal. C, Particles and fields,
2/2007, Letnik:
49, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The strongest constraint on Vtb presently comes from the 3×3 unitarity of the CKM matrix, which fixes Vtb to be very close to one. If unitarity is relaxed, current information from top production at ...Tevatron still leaves open the possibility that Vtb is sizably smaller than one. In minimal extensions of the standard model with extra heavy quarks, the unitarity constraints are much weaker, and the EW precision parameters entail the strongest bounds on Vtb. We discuss the experimental perspectives of discovering and identifying such new physics models at the Tevatron and the LHC, through a precise measurement of Vtb from the single top cross sections and by the study of processes where the extra heavy quarks are produced.
Abstract The Belle II collaboration has initiated a program to upgrade its detector in order to address the challenges set by the increase of the SuperKEKB collider luminosity, targeting 6×10 35 cm 2 ...s -1 . A monolithic CMOS pixel sensor named OBELIX (Optimized BELle II pIXel) is proposed to equip 5 detection layers upgrading the current vertex detector. Based on the existing TJ-Monopix2, OBELIX is currently designed in 180 nm CMOS process.
We reconcile the 1/Nc expansion with the observed η−η′ mass spectrum. The chiral corrections introduced for that purpose are natural and consistent with the octet–singlet mixing angle θ=−(22±1)° ...extracted from phenomenology in the large Nc limit.
A
bstract
We discuss the possibilities of assessing a non-zero
$ C_{{^{{7\gamma }}}^{\prime } $
from the direct and the indirect measurements of the photon polarization in the exclusive
b
→
s
γ
(*)
...decays. We focus on three methods and explore the following three decay modes:
B
→
K
*
(→
K
S
π
0
)
γ
,
B
→
K
1
(→
Kππ
)
γ
, and
B
→
K
*
(→
Kπ
)
ℓ
+
ℓ
−
. By studying different New Physics scenarios we show that the future measurement of conveniently defined observables in these decays could provide us with the full determination of
C
7
γ
and
$ C_{{^{{7\gamma }}}^{\prime } $
.
From the LHC to future colliders De Roeck, A; Ellis, J; Grojean, C ...
The European physical journal. C, Particles and fields,
04/2010, Letnik:
66, Številka:
3-4
Journal Article
Recenzirano
Odprti dostop
Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and ...prospects of LHC running with 10 to 300 fb−1 of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10 fb−1 of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, the Working Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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