368 research outputs found
A safe CFT at large charge
We apply the large-charge limit to the first known example of a
four-dimensional gauge-Yukawa theory featuring an ultraviolet interacting fixed
point in all couplings. We determine the energy of the ground state in presence
of large fixed global charges and deduce the global symmetry breaking pattern.
We show that the fermions decouple at low energy leaving behind a confining
Yang-Mills theory and a characteristic spectrum of type I (relativistic) and
type II (non-relativistic) Goldstone bosons. Armed with the knowledge acquired
above we finally arrive at establishing the conformal dimensions of the theory
as a triple expansion in the large-charge, the number of flavors and the
controllably small inverse gauge coupling constant at the UV fixed point. Our
results unveil a number of noteworthy properties of the low-energy spectrum,
vacuum energy and conformal properties of the theory. They also allow us to
derive a new consistency condition for the relative sizes of the couplings at
the fixed point.Comment: 18 pages, published version, some typos correcte
Charging the Conformal Window
We investigate the properties of near-conformal dynamics in a sector of large
charge when approaching the lower boundary of the conformal window from the
chirally broken phase. To elucidate our approach we use the time-honored
example of the phenomenologically relevant SU(2) color theory featuring
Dirac fermions transforming in the fundamental representation of the gauge
group. In the chirally broken phase we employ the effective pion Lagrangian
featuring also a pseudo-dilaton to capture a possible smooth
conformal-to-non-conformal phase transition. We charge the baryon symmetry of
the Lagrangian and study its impact on the ground state and spectrum of the
theory as well as the would-be conformal dimensions of the lowest large-charge
operator. We moreover study the effects of and dependence on the fermion mass
term.Comment: 15 page
Near-Conformal Dynamics at Large Charge
We investigate four-dimensional near-conformal dynamics by means of the
large-charge limit. We first introduce and justify the formalism in which
near-conformal invariance is insured by adding a dilaton and then determine the
large-charge spectrum of the theory. The dilaton can also be viewed as the
radial mode of the EFT. We calculate the two-point functions of charged
operators. We discover that the mass of the dilaton, parametrising the
near-breaking of conformal invariance, induces a novel term that is logarithmic
in the charge. One can therefore employ the large-charge limit to explore
near-conformal dynamics and determine dilaton-related properties
Biotechnological synthesis of succinic acid by actinobacillus succinogenes by exploitation of lignocellulosic biomass
Succinic acid is increasingly used in pharmaceutical industries, for the production of additives in food
industries, in agriculture and in refinery processes as a precursor of many chemical compounds among which
the most important is the succinate salt. It is also used as an ion chelator and surfactant, and for the
biochemicals production. Currently, succinic acid is mainly produced through chemical petroleum-based
processes, usually from n-butane using maleic anhydride. However, the use of petrochemical feedstocks
raises serious environmental problems, due to the higher values of temperature and pressure required. The
biotechnological production of succinic acid by microbial conversion of lignocellulosic biomass is attracting
growing interest due to the environmental and economic advantages offered.
This research is focused on the exploitation of Arundo donax (Giant reed) as a source of lignocellulosic
biomass. Arundo donax is a perennial crop particularly suitable for energy production, as it offers high yields
per hectare, even in partially fertile or polluted soils, not used for agriculture. Hydrolyzate of Arundo donax will
be used as growth media for the Actinobacillus succinogenes 130Z, a bacterium typically found in the bovine
rumen, that is recognized as one of the most promising for the biotechnological production of succinic acid, as
it is able to produce higher concentrations of succinic acid. The experimental analysis is carried out to
optimize the production of succinic acid taking into account the effect of the most critical parameters of the
process (microbial biomass, pH, reducing sugars, volatile fatty acids, and succinic acid). Tests have shown
that in 48h the sugars are completely biodegraded with a total production of bio-succinic acid of 5.9 g for 9.1 g
of reducing sugars, an hourly production 0.12 g h-1 with a yield equal to 65%
Standard model anomalies: Lepton flavour non-universality and lepton g-2
We critically analyze the body of results that hints to the existence of New
Physics from possible violations of lepton universality observed by the LHCb
experiment in the ratios and to the lepton
anomalies. The analysis begins with a theoretical, in depth, study of the
ratios and as well as the process . Here we consider the impact of complex Wilson coefficients and
derive constraints on their imaginary and real parts. We then move to a
comprehensive comparison with experimental results. We show that, by fitting a
single Wilson coefficient, the deviations from the Standard Model are at the
level when including only the hadronic insensitive observables
while it increases to when including also the hadronic sensitive
ones. When switching on all relevant Wilson coefficients and combining both
hadronic sensitive and insensitive data into the fit, the deviation from the
Standard Model peaks at 7.2 and decreases at the level if
we assume that the central values of and are taken to be
unity. We further estimate the non-perturbative long distance hadronic
contributions and show that their inclusion still requires New Physics to fit
the data. We then introduce the lepton anomalies results. Different
theoretical models are considered that can explain the discrepancies from the
Standard Model. In the final part of our work we estimate the impact of the
forthcoming data from LHCb (coming from LHC Run3) and Belle II, when it will
have accumulated about
The mediterranean sea we want
open58siThis paper presents major gaps and challenges for implementing the UN Decade of Ocean Science for Sustainable Development (2021-2030) in the Mediterranean region. The authors make recommendations on the scientific knowledge needs and co-design actions identified during two consultations, part of the Decade preparatory-phase, framing them in the Mediterranean Sea’s unique environmental and socio-economic perspectives. According to the ‘Mediterranean State of the Environment and Development Report 2020’ by the United Nations Environment Programme Mediterranean Action Plan and despite notable progress, the Mediterranean region is not on track to achieve and fully implement the Sustainable Development Goals of Agenda 2030. Key factors are the cumulative effect of multiple human-induced pressures that threaten the ecosystem resources and services in the global change scenario. The basin, identified as a climate change vulnerability hotspot, is exposed to pollution and rising impacts of climate change. This affects mainly the coastal zones, at increasing risk of extreme events and their negative effects of unsustainable management of key economic assets. Transitioning to a sustainable blue economy is the key for the marine environment’s health and the nourishment of future generations. This challenging context, offering the opportunity of enhancing the knowledge to define science-based measures as well as narrowing the gaps between the Northen and Southern shores, calls for a joint (re)action. The paper reviews the state of the art of Mediterranean Sea science knowledge, sets of trends, capacity development needs, specific challenges, and recommendations for each Decade’s societal outcome. In the conclusions, the proposal for a Mediterranean regional programme in the framework of the Ocean Decade is addressed. The core objective relies on integrating and improving the existing ocean-knowledge, Ocean Literacy, and ocean observing capacities building on international cooperation to reach the “Mediterranean Sea that we want”.openCappelletto M.; Santoleri R.; Evangelista L.; Galgani F.; Garces E.; Giorgetti A.; Fava F.; Herut B.; Hilmi K.; Kholeif S.; Lorito S.; Sammari C.; Lianos M.C.; Celussi M.; D'alelio D.; Francocci F.; Giorgi G.; Canu D.M.; Organelli E.; Pomaro A.; Sannino G.; Segou M.; Simoncelli S.; Babeyko A.; Barbanti A.; Chang-Seng D.; Cardin V.; Casotti R.; Drago A.; Asmi S.E.; Eparkhina D.; Fichaut M.; Hema T.; Procaccini G.; Santoro F.; Scoullos M.; Solidoro C.; Trincardi F.; Tunesi L.; Umgiesser G.; Zingone A.; Ballerini T.; Chaffai A.; Coppini G.; Gruber S.; Knezevic J.; Leone G.; Penca J.; Pinardi N.; Petihakis G.; Rio M.-H.; Said M.; Siokouros Z.; Srour A.; Snoussi M.; Tintore J.; Vassilopoulou V.; Zavatarelli M.Cappelletto M.; Santoleri R.; Evangelista L.; Galgani F.; Garces E.; Giorgetti A.; Fava F.; Herut B.; Hilmi K.; Kholeif S.; Lorito S.; Sammari C.; Lianos M.C.; Celussi M.; D'alelio D.; Francocci F.; Giorgi G.; Canu D.M.; Organelli E.; Pomaro A.; Sannino G.; Segou M.; Simoncelli S.; Babeyko A.; Barbanti A.; Chang-Seng D.; Cardin V.; Casotti R.; Drago A.; Asmi S.E.; Eparkhina D.; Fichaut M.; Hema T.; Procaccini G.; Santoro F.; Scoullos M.; Solidoro C.; Trincardi F.; Tunesi L.; Umgiesser G.; Zingone A.; Ballerini T.; Chaffai A.; Coppini G.; Gruber S.; Knezevic J.; Leone G.; Penca J.; Pinardi N.; Petihakis G.; Rio M.-H.; Said M.; Siokouros Z.; Srour A.; Snoussi M.; Tintore J.; Vassilopoulou V.; Zavatarelli M
Search for heavy long-lived multi-charged particles in pp collisions at √s = 8 TeV using the ATLAS detector
A search for heavy long-lived multi-charged particles is performed using the ATLAS detector at the LHC. Data collected in 2012 at s√ = 8 TeV from pp collisions corresponding to an integrated luminosity of 20.3 fb−1 are examined. Particles producing anomalously high ionisation, consistent with long-lived massive particles with electric charges from |q|=2e to |q|=6e are searched for. No signal candidate events are observed, and 95% confidence level cross-section upper limits are interpreted as lower mass limits for a Drell–Yan production model. The mass limits range between 660 and 785 GeV
Search for a new resonance decaying to a W or Z boson and a Higgs boson in the ll/lv/vv + bb final states with the ATLAS detector
A search for a new resonance decaying to a W or Z boson and a Higgs boson in the ll/lv/vv + bb final states is performed using 20.3 fb −1 of pp collision data recorded at √ s = 8 TeV with the ATLAS detector at the Large Hadron Collider. The search is conducted by examining the W H / Z H invariant mass distribution for a localized excess. No significant deviation from the Standard Model background prediction is observed. The results are interpreted in terms of constraints on the Minimal Walking Technicolor model and on a simplified approach based on a phenomenological Lagrangian of Heavy Vector Triplets
Search for anomalous couplings in the W tb vertex from the measurement of double differential angular decay rates of single top quarks produced in the t-channel with the ATLAS detector
The electroweak production and subsequent decay of single top quarks is determined by the properties of the Wtb vertex. This vertex can be described by the complex parameters of an effective Lagrangian. An analysis of angular distributions of the decay products of single top quarks produced in the t -channel constrains these parameters simultaneously. The analysis described in this paper uses 4.6 fb−1 of proton-proton collision data at √s =7 TeV collected with the ATLAS detector at the LHC. Two parameters are measured simultaneously in this analysis. The fraction f 1 of decays containing transversely polarised W bosons is measured to be 0.37 ± 0.07 (stat.⊕syst.). The phase δ − between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be −0.014π ± 0.036π (stat.⊕syst.). The correlation in the measurement of these parameters is 0.15. These values result in two-dimensional limits at the 95% confidence level on the ratio of the complex coupling parameters g R and V L, yielding Re[g R /V L] ∈ [−0.36, 0.10] and Im[g R /V L] ∈ [−0.17, 0.23] with a correlation of 0.11. The results are in good agreement with the predictions of the Standard Model
Muon reconstruction performance of the ATLAS detector in proton–proton collision data at √s = 13 TeV
This article documents the performance of the ATLAS muon identification and reconstruction using the LHC dataset recorded at √s = 13 TeV in 2015. Using a large sample of J/ψ→μμ and Z→μμ decays from 3.2 fb−1 of pp collision data, measurements of the reconstruction efficiency, as well as of the momentum scale and resolution, are presented and compared to Monte Carlo simulations. The reconstruction efficiency is measured to be close to 99% over most of the covered phase space (|η| 2.2, the pT resolution for muons from Z→μμ decays is 2.9 % while the precision of the momentum scale for low-pT muons from J/ψ→μμ decays is about 0.2%
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