A small set of final prototypes of the ATLAS Inner Detector silicon tracker (Pixel and SCT) were used to take data during the 2004 Combined Test Beam. Data were collected from runs with beams of ...different flavour (electrons, pions, muons and photons) with a momentum range of 2 to 180 GeV/c. Four independent methods were used to align the silicon modules. The corrections obtained were validated using the known momenta of the beam particles and were shown to yield consistent results among the different alignment approaches. From the residual distributions, it is concluded that the precision attained in the alignment of the silicon modules is of the order of 5 micrometers in their most precise coordinate.
In models with large extra dimensions, “miniature” black holes (BHs) might be produced in high-energy proton–proton collisions at the Large Hadron Collider (LHC). In the semi-classical regime, those ...BHs thermally decay, giving rise to large-multiplicity final states with jets and leptons. On the other hand, similar final states are also expected in the production of electroweak sphaleron/instanton-induced processes. We investigate whether one can discriminate these scenarios when BH or sphaleron-like events are observed in the LHC using machine learning (ML) methods. Classification among several BH scenarios with different numbers of extra dimensions and the minimal BH masses is also examined. In this study we consider three ML models: XGBoost algorithms with (1) high- and (2) low-level inputs, and (3) a Residual Convolutional Neural Network. In the latter case, the low-level detector information is converted into an input format of three-layer binned event images, where the value of each bin corresponds to the energy deposited in various detector subsystems. We demonstrate that only a small number of detected events are sufficient to effectively discriminate between the sphaleron and BH processes. Separation between BH scenarios with different minimal masses is possible with an order of 10 events passing the preselection. A sufficient number of events could be observed in combined Run-2 and -3 data, if the production cross section is not much smaller than the present limit
∼
0.1
fb. We find, however, that a large number of events is needed to discriminate between BH hypotheses with the same minimal BH mass, but different numbers of extra dimensions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
16.
Exploring CP violation in H→τ+τ-γ Aakvaag, Erlend; Fomin, Nikolai; Lipniacka, Anna ...
The European physical journal. C, Particles and fields,
03/2024, Letnik:
84, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We propose a method of measuring the CP-odd part of the Yukawa interaction of Higgs boson and
τ
leptons by observing the forward–backward asymmetry in the decay
H
→
τ
+
τ
-
γ
. The source of such ...asymmetry is the interference of the CP-even loop-level contribution coming from
H
→
Z
γ
→
τ
+
τ
-
γ
decay channel with the contribution from tree-level CP-odd Yukawa interaction. We find that the CP violating effect is maximum when the invariant mass of the
τ
+
τ
-
pair is equal to the mass of the
Z
boson. We propose and utilise various Dalitz plot asymmetries to quantify the maximal size of the asymmetry and perform Monte Carlo simulations to study the feasibility of measuring it in the high luminosity phase of the Large Hadron Collider (HL-LHC).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract We propose a method of measuring the CP-odd part of the Yukawa interaction of Higgs boson and $$\tau $$ τ leptons by observing the forward–backward asymmetry in the decay $$H \rightarrow ...\tau ^+ \, \tau ^- \, \gamma $$ H → τ + τ - γ . The source of such asymmetry is the interference of the CP-even loop-level contribution coming from $$H \rightarrow Z \, \gamma \rightarrow \tau ^+ \, \tau ^- \, \gamma $$ H → Z γ → τ + τ - γ decay channel with the contribution from tree-level CP-odd Yukawa interaction. We find that the CP violating effect is maximum when the invariant mass of the $$\tau ^+\,\tau ^-$$ τ + τ - pair is equal to the mass of the Z boson. We propose and utilise various Dalitz plot asymmetries to quantify the maximal size of the asymmetry and perform Monte Carlo simulations to study the feasibility of measuring it in the high luminosity phase of the Large Hadron Collider (HL-LHC).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Porphyrias are diverse disorders that arise from various inherited enzyme defects in the heme biosynthesis pathway, except for porphyria cutanea tarda (PCT), in which the enzyme deficiency in most ...cases is acquired. The biosynthetic blocks resulting from the defective enzymes are largely expressed either in the liver or bone marrow, the sites where the majority of heme is produced. Although the pathophysiologic mechanisms of the clinical manifestations of the porphyrias are not fully understood, two cardinal features prevail: skin photosensitivity and neurologic symptoms of intermittent autonomic neuropathy, acute neurovisceral attacks, and disorders of the nervous system. The primary diagnosis of the proband is based on biochemical testing, which is not always able to identify acute porphyrias, especially in asymptomatic family carriers when heme precursors and porphyrins excretion is normal, low-normal and high-reduced values of enzyme activity overlap, and hematological diseases responsible for abnormal blood cells distribution coexist. Molecular analysis of gene mutations responsible for each type of porphyria is the best diagnostic approach for symptomatic as well as presymptomatic gene carriers.
Abstract We propose a method of measuring the CP-odd part of the Yukawa interaction of Higgs boson and $$\tau $$ τ leptons by observing the forward–backward asymmetry in the decay $$H \rightarrow ...\tau ^+ \, \tau ^- \, \gamma $$ H → τ + τ - γ . The source of such asymmetry is the interference of the CP-even loop-level contribution coming from $$H \rightarrow Z \, \gamma \rightarrow \tau ^+ \, \tau ^- \, \gamma $$ H → Z γ → τ + τ - γ decay channel with the contribution from tree-level CP-odd Yukawa interaction. We find that the CP violating effect is maximum when the invariant mass of the $$\tau ^+\,\tau ^-$$ τ + τ - pair is equal to the mass of the Z boson. We propose and utilise various Dalitz plot asymmetries to quantify the maximal size of the asymmetry and perform Monte Carlo simulations to study the feasibility of measuring it in the high luminosity phase of the Large Hadron Collider (HL-LHC).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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